David Lazarus

[David Lazarus]

The Butterflies of Essex
2024 Year in Review

Orange-tip Anthocharis cardamines

Summary
The Orange-tip is of least concern in the vice-counties of North & South Essex, and is a low priority for butterfly conservation in Essex. Despite this, I personally would not call it common and widespread which is how it is described. Considering Orange-tip and Green-veined White share many of the requirements for habitats and site conditions, and many of these life-cycle requirements are available in the floodplain of the River Chelmer here in Chelmsford, numbers of Orange-tip sightings were fewer than Green-veined White over the course of its flight period. I am concerned for its future abundance and distribution within Essex. During 2024 they were a welcome site in the Spring but then it felt like they were gone far too quickly. The weather conditions were not great in the Spring which meant I did not travel as much as I did during the rest of the year. Subsequently, I have limited data at fewer locations to analyse and evaluate.

The 2024 distribution of the Orange-tip, limited to recorded sightings on the Butterflies for the New Millennium Online website, indicates that recorded sightings were not widespread and they were sparse with the notable exceptions of Chelmsford and mid-Essex, the north-east of Essex, and along the Thames Estuary into East London.

2024 distribution of Orange-tip within Essex
Source: Butterflies for the New Millennium Online

The recorded sightings over the past 10 years indicates a wider distribution with higher concentrations within the areas already mentioned with the north-west of Essex also having more recorded sightings. I am unsure if this indicates that 2024 was a particularly poor year for Orange-tip or not.

2014-2024 distribution of Orange-tip within Essex
Source: Butterflies for the New Millennium Online

As already mentioned, I did not get out and about during the flight period of the Orange-tip and my own distribution data is therefore of limited use:

2024 site locations where Orange-tip was recorded

The abundance during 2024 at these site locations are as follows:

2024 Orange-tip Total Abundance by Location
Source: iRecord

A grand total of 203 which, I think, is no more than okay but considering the weather and the limited chances to get out to search for butterflies I should not be too displeased. 132 of the 203 were local sightings within Chelmsford and mid-Essex.

The 2024 abundance over time was as follows:

2024 Orange-tip Total Abundance by Date
Source: iRecord

The first sighting was on the 11th of April within Baddow Meads, with the final sighting on the 23rd of May at Meadgate Fields Open Space some 6 weeks later. The season peaked locally from the 09th to 12th of May with the most seen on any one day 21 on the 09th of May along the River Chelmer at Chelmer Valley Riverside Local Nature Reserve. In the North Essex vice-county the standout location was Great Holland Pits on the 02nd of May when 14 were seen with another 8 seen in the area including The Naze - 22 in total. One Tree Hill at Langdon Hills Country Park was the location with the highest recorded sightings of 33 with the most seen on one visit being 17 on the 11th of May.

Highlights
It is always a joy to see my first Orange-tip of the year and it signals the start of Spring and the emergence of those butterflies that do not over-winter as adults. My memory of the Orange-tip season was wading through water locally in my Wellington Boots searching the patches of tall herbaceous plants within the glade at Meadgate Fields Open Space and across the floodplain. It was though the local nature reserves along the River Chelmer and the River Can that produced the most regular sightings during the peak of their flight period.
I am not particularly interested in aberrations, however I did wonder why the females at Meadgate Fields Open Space had light grey discoidal spots and apical tips. Then I noticed the males had pinpoint discoidal spots. It was only later at One Tree Hill that I actually came across a female of the species to reveal that I was not just seeing things - mind you many of the Green-veined White were very light and a few virtually white Small White also appeared during April & May 2024. I will return to this in the Meadgate Fields Open Space review.

[David Lazarus]

The Butterflies of Essex 2024 Year in Review continued

South Essex

The following locations are where sightings of Orange-tip were recorded by me during 2024 within South Essex:

2024 Orange-tip recorded sightings
South Essex site locations

Baddow Meads & Meadgate Fields Open Space

Baddow Meads and Meadgate Fields Open Space

As with Green-veined White, the habitats of the River Chelmer floodplain, which is composed of the scrub-bordered open grasslands of Baddow Meads and its channels, as well as the riverbanks themselves, and the riverine habitats either side, which includes scrubland, marsh, and wet mixed deciduous woodland, is ideal habitat for Orange-tip. The main larval food sources are the large patches of Garlic Mustard Alliaria petiolata within dappled shade, and Hedge Mustard Sisymbrium officinale. There is still some Cuckoo-flower Cardamine pratensis within the open grasslands of the floodplain, indicating that once this wildflower could be found all over Baddow Meads. However, conversion to pasture land, with intensive agricultural practices, such as the addition of nutrients and the use of herbicides, has destroyed what used to be a forb-rich meadow. It is now a hay meadow. I have never seen an Orange-tip on or anywhere near the remaining Cuckoo-flower. Like my sightings of Green-veined White, most of the recorded Orange-tip sightings are along the woodland edge where large patches of the previously mentioned tall herbaceous plants grow, and these include Garlic Mustard, Cow Parsley Anthriscus sylvestris, and Nettles Urtica dioica. I believe they favour these habitats as much for the microclimate they produce than for any other reason. The fact that Orange-tip are hard to spot when they are perching with closed wings on Cow Parsley suggests that plant is used by Orange-tip to perch and roost as the undersides are perfect camouflage for avoiding predation [see image below].
Above I mentioned that different types of aberrations occur within the females and males of Orange-tip within Meadgate Fields Open Space and across other locations within the floodplains and riverbanks of both the River Chelmer and the River Can where most of my sightings occur. There was quite a significant difference between the females I saw locally and those I saw at One Tree Hill and Great Holland Pits. All but the last female I saw in Meadgate Fields Open Space presented with the usual black parts (discoidal spot and apical tip) replaced by pale grey, which is the form ab. decolorata. To my surprise most of the males presented with the discoidal spot of the forewings reduced to a small speck, ab. antiquincunx, and one or two where the discoidal spot of the forewings is pupilled ab. pupillata. Most of the local Orange-tip seen during 2024 were aberrations. Very strange - and I obviously do not know the reason for this.

Meadgate Fields Open Space - Orange-tip were seen on 6 occasions with the first sighting on the 26th of April and the final sighting on the 23rd of May. The most seen on any one day was 8 on the 29th of April. Total: 20
Baddow Meads - Orange-tip were seen on 10 occasions with the first sighting on the 11th of April, which was the first one seen in Essex during 2024. Only a few were seen each time, and the final one was seen on the 20th of May. Total: 17
Also, Barnes Mill Lock - 2 sightings on the 18th of April. Total: 2
Meadgate Park - Orange-tip were seen on 6 occasions with the first sighting [and photograph] on the 14th of April. Singles were seen flying up and down the scrub edge only. The last sighting was on the 08th of May. Total: 10
Also, Garden on Meadgate Avenue - a single sighting on the 09th of May. Total: 1
The Blue Lion - a single sighting on the 14th of April. Total: 1
Total for south-east of the River Chelmer: 51

Orange-tip male
Meadgate Park 14/04/2024

Orange-tip male
Meadgate Park 14/04/2024

Orange-tip ab. antiquincunx male
Meadgate Park 14/04/2024

Orange-tip ab. pupillata male
Meadgate Park 25/04/2024

Orange-tip ab. decolorata female
Meadgate Fields Open Space 26/04/2024

Orange-tip ab. decolorata female
Meadgate Fields Open Space 26/04/2024

Orange-tip male
Meadgate Park 26/04/2024

Orange-tip ab. pupillata male
Meadgate Park 26/04/2024

Orange-tip ab. decolorata female
Meadgate Fields Open Space 29/04/2024

Orange-tip ab. decolorata female
Meadgate Fields Open Space 29/04/2024

Orange-tip ab. decolorata female
Meadgate Fields Open Space 29/04/2024

Orange-tip male
Meadgate Fields Open Space 29/04/2024

Orange-tip ab. antiquincunx male
Meadgate Fields Open Space 29/04/2024

Orange-tip male
Meadgate Fields Open Space 30/04/2024

Orange-tip female
Baddow Meads 15/05/2024

Orange-tip female ovipositing
Baddow Meads 15/05/2024

Orange-tip female [species]
Meadgate Fields Open Space 23/05/2024

Danbury Ridge Nature Reserves & Danbury Common

Danbury Ridge Nature Reserves

Not particularly good for Orange-tip with very few seen - although I was not able to visit as often as I would have preferred.

Blake's Wood - single sighting on the 13th of April. Total: 1
Lingwood Common - single sighting on the 13th of April. Total: 1
Pheasanthouse Farm Nature Reserve - single visit on the 13th of April. Total: 1
The Ridge - single sighting on the 13th of April. Total: 1

no images

Danbury Common

There are large patches of Garlic Mustard Alliaria petiolata at various locations within Danbury Common and at Backwarden Nature Reserve which would suggest that Orange-tip are in greater numbers than the few that I saw on one visit in the second week of May.

Danbury Common - only one visit on the 10th of May. Total: 4

no images

Maldon Wick Nature Reserve & Hazeleigh Hall Wood

Maldon Wick Nature Reserve & Hazeleigh Hall Wood

Given that the habitats at Maldon Wick are favourable to a metapopulation of Orange-tip colonies, and because of the good numbers I saw on the single visit I made during the second week of May, I think that recorded sightings would probably be good at this location if visited regularly during the flight period.

Maldon Wick Nature Reserve - a single visit on the 10th of May. Total: 15

Orange-tip male
Maldon Wick Nature Reserve 10/05/2024

One Tree Hill - Johnson's Meadows

One Tree Hill

One Tree Hill has favourable habitat with abundant larval food sources and nectar-rich Spring flowering plants. The female Orange-tip seemed to favour Hedge Mustard Sisymbrium officinale edging the path along the top of the ridge running past the top of Johnson's Meadows. This site was the place I recorded more sightings than any other location, although they were seen while I was searching for the Grizzled Skipper colony.

One Tree Hill - Orange-tip were seen on 3 occasions between the 01st of May and the 19th of May with the highest total for a single visit being 17 on the 11th of May. Total: 33

Orange-tip female [first sighting of the species]
One Tree Hill 01/05/2024

Orange-tip female
One Tree Hill 11/05/2024

Orange-tip female
One Tree Hill 11/05/2024

Orange-tip female ovipositing
One Tree Hill 19/05/2024

Orange-tip female ovipositing
One Tree Hill 19/05/2024

[David Lazarus]

The Butterflies of Essex 2024 Year in Review

North Essex

The following locations are where sightings of Orange-tip were recorded by me during 2024 within North Essex:

2024 Orange-tip recorded sightings
North Essex site locations

Admirals Park Local Nature Reserve & River Can

Admirals Park Local Nature Reserve & River Can

The River Can flows into Chelmsford from the west and joins the River Chelmer in the city centre. Admirals Park Local Nature Park is located on the floodplain of the River Can. The riverbanks have large patches of Garlic Mustard Alliaria petiolata, amongst very large patches of Cow Parsley Anthriscus sylvestris and Nettles Urtica dioica, all growing under trees producing a warm, damp microclimate with dappled shade during Spring. It is common to see Orange-tip all along the river as far as Writtle and probably beyond.

Admirals Park LNR & River Can - Orange-tip were seen on four occasions with the first sighting on the 24th of April with 12 seen on the 07th of May. The final sighting was on the 11th of May although I did not walk the riverbanks of the Can as often as I would prefer. Total: 21
Garden on Chignal Road - Orange-tip were seen on the 30th of April. Total: 5

Orange-tip female
Admirals Park Local Nature Reserve 07/05/2024

Orange-tip female
Admirals Park Local Nature Reserve 07/05/2024

Orange-tip female
Admirals Park Local Nature Reserve 07/05/2024

Orange-tip female
Admirals Park Local Nature Reserve 07/05/2024

Chelmer Valley Riverside Local Nature Reserve, Newlands Grove Nature Reserve, & Little Waltham Meadows Nature Reserve

Chelmer Valley Local Nature Reserve, Newlands Grove Nature Reserve, & Little Waltham Meadows Nature Reserve

Similar habitats and plant communities exist along the riverbanks of the River Chelmer flowing in from the north of Chelmsford via these three nature reserves. They are not blessed with high numbers of butterflies, but recorded sightings of Orange-tip were fairly good.

Chelmer Valley Riverside Local Nature Reserve - Orange-tip were seen on two occasions during May, the 09th & the 12th. Total: 21
Newlands Grove Nature Reserve - a single visit on the 12th of May. Total: 4
Little Waltham Meadows Nature Reserve - a single visit on the 12th of May. Total: 6
Broomfield - a single visit on the 12th of May. Total: 1
Also, the northern bank of the River Chelmer flowing east towards Sandford Lock - Orange-tip were seen on 5 occasions from the 18th of April to the 17th of May. Total: 12
Chaucer Road Meadow - a single occasion on the 09th of May. Total: 2
Total for the northern bank of the River Chelmer & North Chelmsford: 46

Orange-tip male
River Chelmer 25/04/2024

Orange-tip male
River Chelmer 25/04/2024

Orange-tip female
Chaucer Road Meadow 29/04/2024

Orange-tip male
River Chelmer 29/04/2024

Orange-tip male
River Chelmer 29/04/2024

Orange-tip female
Chaucer Road Meadow 09/05/2024

Orange-tip pair
Chaucer Road Meadow 09/05/2024

Orange-tip female
Chaucer Road Meadow 09/05/2024

Orange-tip male
Chelmer Valley Local Nature Reserve 12/05/2024

Orange-tip female
Little Waltham Meadows Nature Reserve 12/05/2024

Terling

There is suitable habitat along the banks of the River Ter.

Terling - Orange-tip sightings have not come through to iRecord from the UK Butterfly Monitoring Scheme records.
Gamble's Green - a single visit on 13th of May. Total: 1

Orange-tip male
Terling 13/05/2024

Great Holland Pits Nature Reserve

Great Holland Pits

I would expect to see far more Orange-tip at Great Holland Pits Nature Reserve if I visited the site more often during the flight period as it has suitable habitat within the rides through the wet, mixed deciduous woodland, with ample larval food sources and nectar-rich Spring wildflowers.

Great Holland Pits - just one visit on the 02nd of May. Total: 14
Plus, a couple more on Little Clacton Road and at Kirby Cross. Total: 2

Orange-tip male
Great Holland Pits Nature Reserve 02/05/2024

The Naze

The Naze

I only managed one visit during the flight period. I would not expect The Naze to be especially suitable for large numbers of Orange-tip. They were seen nectaring and laying eggs on Hedge Mustard Sisymbrium officinale and/or its agricultural cultivar field escapees in some rough ground.

The Naze - a single visit on the 02nd of May. Total: 6

Orange-tip male
The Naze 02/05/2024

Orange-tip male
The Naze 02/05/2024

Orange-tip male
The Naze 02/05/2024

[essexbuzzard]

Hi David.

The Orange Tip is widespread and fairly common throughout the county, but the number of adults varies each year. As you have said, the main caterpillar foodplant in Essex is garlic mustard but, being biennial, the amount of it each year is highly variable. It was scarce in 2023, but there was a bumper crop of it last year, so I’m hoping that will lead to better numbers of Orange Tips this year.

Another major problem, at least in towns and villages, is the highly destructive and deep flailing of road,footpath and cycle path verges, in May, right in the middle of the Orange Tips season. This not only kills any roosting adults, but also all the eggs and caterpillars, along with their foodplants. All dead. Thousands must be killed each year in Essex, perhaps millions in the country as a whole. It doesn’t take long to imagine the damage this does to Orange Tips populations, as well as many other species.

[David Lazarus]

The Orange Tip is widespread and fairly common throughout the county, but the number of adults varies each year.

Thanks Mark, I appreciate the feedback. It is good to know that your experience of Orange-tip in Essex is more positive. As you say, "the highly destructive and deep flailing of road, footpath and cycle path verges, in May" is a real problem for their lifecycle. As I mentioned, people do not appreciate the aesthetical qualities of large patches of what they consider to be weeds. This is particularly true in recreational landscapes where dog walkers and ramblers are catered for before the needs of wildlife. I am not sure those involved in butterfly conservation are going to buy a kilogram of Garlic Mustard Alliaria petiolata seed to spread in suitable habitats for Orange-tip either.

[Neil Freeman]

I am enjoying your detailed reports from your part of the country. Looking foward to some more.

Cheers,

Neil.

[David Lazarus]

Thanks Neil.

Nearly a 1/3 of the way through the review of all 34 species of butterfly seen in Essex. The next species is the Green Hairstreak. Out of all 34 species this is the one I know least about. The Green Hairstreak is also at the bottom of my list of sightings with just the one which was seen in 2024. For this reason my data and knowledge is obviously limited, so I have decided to use all recorded sightings for Essex and have produced distribution maps, tables and graphs using this data. With the reading I have been doing, this will help me to understand the required habitat, locations, and where I can search for Green Hairstreak in Essex. I will then be able to plan 2025's butterfly searches. I have decided I need to add the Green Hairstreak to the list of my target species as I am very concerned about this species.

As a bit of information, which helps to explain the recorded sightings for all butterfly species, I have also created a habitat map for Essex - not easy but now completed using Magic Map, OpenStreetMap, and a bit of Photoshop - it is not perfect but it will do:

Habitat Map for Essex
Source: OpenStreetMap & Magic Map modified

The hatched area is where there are the least recorded sightings for all species. This is the area of least population density in Essex and the land use is primarily agricultural - the "Breadbasket of Essex" with large fields of wheat and barley to potato crops and broad beans. This does not mean there are no butterflies in this area. It indicates that most butterflies in this area go unrecorded.

As we will see in the next section on Green Hairstreak, this area is shown on the Butterfly Conservation distribution map for the UK.

[Matsukaze]

The hatched area is where there are the least recorded sightings for all species. This is the area of least population density in Essex and the land use is primarily agricultural - the "Breadbasket of Essex" with large fields of wheat and barley to potato crops and broad beans. This does not mean there are no butterflies in this area. It indicates that most butterflies in this area go unrecorded.

I wonder ... here in Somerset where such habitat is at a premium, interesting species can turn up on it, attracted by the bare ground. It seems to be favoured by Small Tortoiseshells and, if there's suitable areas of foodplant nearby, the likes of Wall Brown and the golden skippers.

[essexbutterflyer]

David, I have been reading some of your reports and throughly enjoying them, but after viewing the quality of the map you have made I am simply blown away! Thank you for compiling so many pieces of info in one place

Zayed

[David Lazarus]

Thank you, Matsukaze. That is an interesting point you make about your experience in Somerset. I think that is something I am trying to highlight, that lots of species go unrecorded for many reasons - mostly, I think, because population densities are low and no one wants to walk through large agricultural fields with monoculture to search along the field margins & hedges which have been destroyed by intensive farming practices. That does not mean that, for instance, there is not a localised colony of a Hairstreak or as you say, Wall that no one knows about. It begs the question whether on a district or county level the current data gives information about the abundance and distribution of each butterfly species or is information about recorded sightings? I am sure they are very similar and give us an 'idea' of what is going on but I suggest the current data is actually incomplete and limited on a county level.

Thank you, Zayed. I am hoping every butterfly enthusiast who either lives in Essex or visits Essex to search for butterflies will find the information I intend to post during the next 10 years useful for finding what they are looking for. Soils, habitats, landscape character, microclimatic conditions as well as my annual field work reviews will help to target species and suitable locations for enjoying their search. Hopefully, we will have a comprehensive resource for Essex butterflies like those of Cornwall, Kent, Warwickshire and many others by the time I finish.

Not that I would recommend anyone visiting Essex to search for butterflies. There are far better places to enjoy butterflies than Essex which is not only limited to 34 species but does not have great numbers of "uncommon" or habitat specialists that are easy to find.

Apart from the lovely Heath Fritillary in the South Essex woods.

Heath Fritillary
Pound Wood 08/06/2024

[David Lazarus]

The Butterflies of Essex
2024 Year in Review

Lycaenidae

Green Hairstreak Callophrys rubi

Summary
The Green Hairstreak is of least concern [GB Red List (2022) for the whole of the UK], and is a medium priority for butterfly conservation although this is kept under review - but also this is for the whole of the UK where abundance and distribution shows significant declines. Although it is described as widespread, this is not the case in Essex. There are large areas where the Green Hairstreak is either absent because there are unsuitable habitats for it to survive or it has undergone local extinction during the last 50 years and/or because of its tendency to exist in small, localised colonies, it goes unrecorded. I am not sure there are many people who search site locations specifically to track down Green Hairstreak especially in locations where it has existed but has not been recorded for a number of years or in places that it has never been recorded yet has suitable habitat, such as the chalk landscape in North-West Essex.
*** There is one person who looks like he does search specifically for Green Hairstreak at Wanstead Flats, and I will come to that.

The 2024 distribution of the Green Hairstreak. limited to recorded sightings on the Butterflies for the New Millennium Online website, indicates that it can only be found in certain locations mostly in the East London, Thames Estuary, and coastal locations such as The Naze. Significantly, there is not one record from the chalk landscape of the north-west of Essex - our only chalk landscape. However, the chalk pits of Chafford Gorges Nature Discovery Park in the south of Essex along the Thames Estuary is one of the go to places for seeing good numbers of Green Hairstreak.

2024 distribution of Green Hairstreak within Essex
Source: Butterflies for the New Millennium Online

The recorded sightings for the last 10 years shows large areas where Green Hairstreak has not been recorded. It also indicates that there have been significant declines of locations where Green Hairstreak have been recorded in the past 10 years compared to recorded sightings from 2024. One of those sites is Backwarden Nature Reserve at Danbury Common near me - no recorded sightings in 2024 and not one since 2021.

2014-2024 distribution of Green Hairstreak within Essex
Source: Butterflies for the New Millennium Online

I wanted to find out the trends for recorded sightings since records began. Unfortunately the records are limited. The records only go as far back as 2009 on iRecords. I have added the records for 1990-1997 from the book by David Corke & Brian Goodey [Corke, D., & Goodey, B., 1997 The Butterflies of Essex Lopinga Books]:

Green Hairstreak distribution trends since 1990
Source: iRecords with Corke & Goodey (1997)

I cannot comment on how accurate Corke & Goodey's distribution maps are - I suspect they did not have the information or data to complete accurate maps for multiple reasons. What stands out if we compare the 1990-1997 sightings [orange] with the 2009-2024 sightings [blue] is that the Danbury Ridge location was a significant location. They state that "several of the strongest colonies are in nature reserves" which should not surprise us as generally this is where people go to record butterfly sightings. They also say that the "management of Little Baddow Heath" has created a Heathland glade within the wooded area at what is now the Danbury Ridge Nature Reserves. And it is still there. It apparently led to the natural recolonisation of the Green Hairstreak there during the 1990s. They obviously did not last long as none have been recorded there since at least 2009 - or have they gone unrecorded? There are 13 of the 24 tetrads from 1990-1997 that have not had a recorded sighting since at least 2009. These are mostly near me in Chelmsford and mid-Essex and in the south between Rainham Marshes and East Tilbury. Of the 2024 recorded sightings, only 4 were at locations where they were in 1990-1997. Most of the current sightings since 2009 were at locations that were not mentioned by Corke & Goodey including the strongest colonies at Wanstead Flats. The limited data does not indicate to me the trends as I had hoped - were they at locations and then disappeared and/or did the distribution of the Green Hairstreak increase during 2009-2023 but then drastically decline in 2024. The limitations of recorded sighting data, I would suggest. However, we might draw the conclusion that Green Hairstreak exist in the south-west of Essex/East London in the vice-county of South Essex, and in the north-east of Essex around Colchester and towards the coast in the vice-county of North Essex. Whether they exist anywhere else in Essex is hard to say. As you can see, most of the sightings are around the coastal locations of Essex with a huge area around the centre of Essex northwards where there have not been any recorded sightings since before 1990 - possibly a lot longer.

As mentioned above, Butterfly Conservation's distribution map for the Green Hairstreak shows this large area where there are no Green Hairstreak:

Green Hairstreak UK distribution
Source: Butterfly Conservation

But as I pointed out in my previous post, the number of recorded sightings for all butterfly species in this area of Essex is virtually non-existent.

The abundance during 2024 for all 78 records [minus one queried record plus one modified queried record] is as follows:

2024 Green Hairstreak Abundance by Location

From this we might infer that Wanstead Flats is the place to go to see Green Hairstreak in good numbers. Everywhere else, Green Hairstreak is seen in ones and twos over the flight period.

2024 Green Hairstreak Abundance by Date

As mentioned earlier, there has been one person who records far more than anyone else and this has created an anomaly in the records. I am assuming the records to be accurate, and that on the 07th of May at Wanstead Flats 27 recorded sightings were made, and 2 days later on the 09th of May 24 recorded sightings were made at the same place. As the peak of the flight period looks to be within the 04th of May and the 24th of May, it would make sense that this person would visit a place that was known to have good numbers and walk the site at the locations that they are probably familiar with to make their count just as I do. Many of the recorded sightings, including at Wanstead Flats, take place on transect walks, which have their limitations especially for species such as the Hairstreaks.

Highlights
On the 11th of May at Johnson's Meadow East, One Tree Hill near Basildon, I managed to see my first ever Green Hairstreak which popped out of a shrub in front of me as I was passing by. As it remained on a sucker along the edge of the meadow without returning to its perch, I might assume it was a female - I don't know. But I had 10 minutes of enjoyment as it wandered around. I even had a glimpse of her upperside. And managed to get some half decent photographs. I might add that this was the only Green Hairstreak recorded sighting at One Tree Hill and the rest of Langdon Hills Country Park during 2024. I will expand on that in the One Tree Hill-Willow Park section that follows:

Green Hairstreak
Johnson's Meadow East 11/05/2024

It is hard to draw any conclusions, but I would suggest that after review that the Green Hairstreak should be considered a high priority for butterfly conservation in Essex before it ends up like the Brown Hairstreak. At least, I think there should be a good search for localised colonies and a thorough count across the county. As mentioned in the previous post, I have added the Green Hairstreak to my list of target species to monitor from 2025.

[David Lazarus]

The Butterflies of Essex 2024 Year in Review continued

South Essex

The following are the 6 main sites for seeing Green Hairstreak in South Essex which are all close to the River Thames and its estuary in the south-west of the county and East London:

Green Hairstreak 2024 recorded sightings
South Essex site locations

Wanstead Flats

Wanstead Flats
Blue - all recorded sightings since 2016
Orange - 2024 recorded sightings

Wanstead Flats is an area of open acid grassland, sports pitches, heath, scrub, woodland, scattered trees and waterbodies, located at the southern end of Epping Forest. I have never been there so I do not know what it is like. Apart from the map above, I have no knowledge of where to search for Green Hairstreak. All I can say is that the maximum recorded sightings for all locations in Essex apart from one is no more than 10. This seems to equate with the experience of those who know more about Green Hairstreak than me who suggest that they can be found in small, localised colonies with around 12-14 sightings of males across the course of their flight period.

The one standout location is Wanstead Flats with a total of 61 Green Hairstreak seen during 2024, with 51 of them seen during 2 visits on the 07th and 09th of May, with a further 4 seen by the same person on two visits in April, leaving 7 and a further 5 seen at the nearby Wanstead Park - most of these other sightings are singles and some were seen on transect walks. A record from one of the 2 visits made in April has been queried by the Essex Recorder who wanted to "double check the abundance figure (33) for this record" thinking that it is "quite high for so early in the flight season". Unfortunately, this query like many records on iRecord that are queried, was not answered. Many people do not log into the website on a browser to acknowledge their notifications so records go unedited with many errors left. I find this to be another one of the problems with the data collection and presentation. I have edited the record for this review to 3. It does give rise to doubts about the 27 and 24 sightings in May - I will see for myself in 2025.

The recorded sightings began in 2016 and there has been at least one recorded sighting every year since.

Wanstead Flats - During 2024, Green Hairstreak were seen on 8 occasions from the 12th of April to the 02nd of June with the highest daily totals on the 07th & 09th of May. Total: 61

Rainham Marshes

Rainham Marshes
Blue - all recorded sightings since 2014
Orange - 2024 recorded sightings

Rainham Marshes has scrubland and areas of rough grassland as well as the marshes and some woodland areas. Just like the Brown Hairstreak, many of the sightings are around the edges of the car park which is bordered by scrub. Again, there are sightings of Green Hairstreak on the path just inside the reserve where Brown Hairstreak adults and ova can be found. There have also been sightings along the Rainham-Purfleet path along the sea wall even at the far end. This path is also bordered by scrub, and the long grass on the reserve side has some of the Green Hairstreak's larval food sources, such as Bird's-foot Trefoil Lotus corniculatus. The reserve is visited by lots of bird spotters and has volunteers that help to explain the amount of recorded sightings. There is also a transect which accounts for 3 of the records. The first record of a sighting on iRecord is from 2014, with sightings in 2017 & 2019. Since 2021 there have been recorded sightings every year.

Rainham Marshes - During 2024, Green Hairstreak were seen on 5 occasions from the 04th of May to the 19th of May with the highest daily total of 4 seen on the 19th of May. Total: 10

Chafford Gorges Nature Discovery Park

Chafford Gorges Nature Discovery Park
Blue - all recorded sightings since 2018
Orange - 2024 recorded sightings

Another site I have never visited, Chafford Gorges Nature Discovery Park has a mosaic of habitats, including rough, calcareous grassland, wildflower meadows, scrub, woodland, ponds with reedbeds and sandy cliffs. Green Hairstreak recorded sightings began in 2018, but there has only been 12 records including the years 2019, 2021, 2023, & 2024.

Chafford Gorges Nature Discovery Park - During 2024, Green Hairstreak have been seen on 4 occasions from the 07th of May to the 29th of May, with the highest daily total of 2 on the 07th of May. Total: 5

EWT Thameside Nature Discovery Park, Coalhouse Fort, & Tilbury Marshes

EWT Thameside Nature Discovery Park, Coalhouse Fort, & Tilbury Marshes
Blue - all recorded sightings since 2018
Orange - 2024 recorded sightings

The Thames Estuary area near East Tilbury is the location for the Essex Wildlife Trust Thameside Nature Discovery Park which is being developed on the Mucking Marshes Landfill. Further south down the Thames Estuary Path is the SSSI Grassland Nature Reserve - Coalhouse Fort, and East Tilbury Marshes. Green Hairstreak sightings have been recorded since 2018. Further sightings included 2019 and 2021, but most sightings were on the transect at Thameside NDP during 2024. It is mostly a nature reserve to observe birds with Mucking Marshes RSPB reserve visible from the visitor centre. There is a mosaic of scrub and rough grasslands with some trees lining the ponds. There have been no recorded sightings at East Tilbury Marshes since 2018.

EWT Thameside Nature Discovery Park & SSSI Grassland Nature Reserve - Coalhouse Fort - During 2024, Green Hairstreak have been seen on 6 occasions from the 10th of May to the 12th of June with the highest daily total of 3 on the 20th of May. Total: 8

Canvey Wick Nature Reserve & Benfleet Downs

Canvey Wick Nature Reserve & Benfleet Downs
Blue - all sightings since 2015
Orange - 2024 recorded sightings

Canvey Wick Nature Reserve is mostly scrubland with woodland areas and some rough grassland. Green Hairstreak sightings have been recorded there since 2015, with sightings recorded in 2017 and each year from 2019. Benfleet Downs is a mosaic of scrub, woodland, and forb-rich grasslands on a south-facing slope. Green Hairstreak have been recorded there from 2019 to 2022 but not in the last two years - perhaps going unrecorded.

Canvey Wick Nature Reserve - During 2024, Green Hairstreak have been seen on 5 occasions from the 28th of April to the 09th of June, with the highest daily total of 4 recorded on the 05th of May. Total: 9

One Tree Hill - Johnson's Meadows & Willow park

One Tree Hill, Johnson's Meadows & Willow Park
Blue - all sightings since 2011
Orange - 2024 recorded sightings

One Tree Hill, Johnson's Meadows are forb-rich wildflower meadows bordered by scrub and hedgerows with woodland areas on either side. Green Hairstreak have been recorded there since 2016 with sightings recorded every year since except for 2020 and 2023. Green Hairstreak sightings have been recorded at Willow Park in 2011, 2013, and 2014 with no sightings for the past 10 years.

One Tree Hill - Johnson's Meadow East - During 2024, Green Hairstreak was only seen once and that was my own recorded sighting. Total: 1

As you can see from the recorded sightings at the 6 locations in the vice-county of South Essex, there have not been many sightings over the years, since 2011 and this is a cause for concern. However, as I have stated previously, this may be because many small localised colonies have gone unrecorded.

[David M]

Your comments regarding this species' distribution in Essex reflect my experience here in the Swansea area, David.

There aren't too many colonies, but where suitable habitat is found they can be reasonably common, though never abundant.

Given the wide range of lhps used, one wonders why it is not more common. Round me they are very much asociated with gorse.

[David Lazarus]

The Butterflies of Essex 2024 Year in Review

North Essex

The following are the six main sites to see Green Hairstreak in North Essex which are mostly towards the north-west of Essex towards the coast.

2024 Green Hairstreak recorded sightings
North Essex site locations

I do not know much about the sites in South Essex when it comes to monitoring Green Hairstreak numbers. I know even less about the sites in North Essex. I am confident Butterfly_Julian knows far more than I do concerning the sites close to where he lives, especially Great Holland Pits, The Naze, and Great Oakley - his home patch.

Essex Wildlife Trust Abbotts Hall Farm

Essex Wildlife Trust Abbotts Hall Farm
Blue - all recorded sightings since 2017
Orange - 2024 recorded sightings

As far as Abbotts Hall Farm is concerned, I know very little apart from knowing that it is the head office of the Essex Wildlife Trust and is currently closed for building work. Their website states that it is a 700-acre site situated on the Blackwater Estuary. It is a nature reserve demonstrating how sustainable coastal defences can lead to the creation of coastal marshes. It links together over 3,000 acres of wildlife-rich land along a 25-kilometre stretch of the Essex Saltmarsh Coast. Habitat restoration and management is using the process of "re-wilding". I do not know how this will affect butterfly populations or abundance. I have never been there as it is difficult to get to by public transport, and is not on my list of sites to monitor.

The first recorded sighting on iRecord is from 2017 and there have been sightings there every year apart from 2020. I would imagine there would have been far more records from 2024 if the reserve had been open to the public.

EWT Abbotts Hall Farm - During 2024, Green Hairstreak sightings were recorded on only one occasion on the 01st of May. Total: 2

Essex Wildlife Trust Abberton Reservoir Nature Discovery Park

Essex Wildlife Trust Abberton Reservoir Nature Discovery Park
Blue - all recorded sightings since 2017
Orange - 2024 recorded sightings

Another site that I have not visited, it is also a good place to see Purple Emperor. It is an internationally famous wetland habitat for seeing waterfowl. It has been designated as a Site of Special Scientific Interest (SSSI), a Special Protection Area (SPA) and a RAMSAR site (Wetland of International Importance). I do not know the range of habitats conducive to butterfly populations, but given that Purple Emperor and Hairstreaks can be seen there, it obviously has patches of scrubland and wooded areas - I would imagine typical ancient, mixed deciduous wet woodland.

Green Hairstreak sightings have been recorded their every year since 2017 apart from 2020. They have also been recorded on a transect at the nearby Layer Breton Heath in 2015, 2016, 2018, & 2019.

EWT Abberton Reservoir - During 2024, Green Hairstreak were seen on 5 occasions from the 13th of April until the 21st of June, with the highest daily total of 3 seen on the 13th of April. Total: 7

Middlewick Ranges

Middlewick Ranges
Recorded sightings 2020, 2022, & 2024

Another site that I have never visited. This week [February 2024] the proposed 1000-house development was rejected on ecological grounds. In their opposition to the proposals for the redevelopment of Middlewick Ranges for housing, the Essex Wildlife Trust says that the tens of hectares of rare acid grassland at Middlewick Ranges encompass the largest extent of this special habitat in Essex, and that the habitat is of the same ecological importance as acid grasslands of fully protected Sites of Special Scientific Interest, like Epping Forest SSSI. Surveys carried out found that it contains a quarter of all UK moth and butterfly species within the 76-hectares. I would imagine that it is actually one of the best sites in Essex, certainly North Essex, to see grassland species as well as those that prefer shrubland and woodland edge. Plus it is close to Friday Wood & Cherry Tree Lane which hosts the premium woodland species. I really should visit.

Monitoring of Green Hairstreak seems to have only just begun with sightings having only been recorded in 2020, 2022, & 2024 according to iRecord. I do not know where the 2024 sightings were located because of problems associated with proper grid map referencing. I have had to manipulate the maps to approximate the locations as best I could but I still do not know which are the 2024 records.

Middlewick Ranges - During 2024, Green Hairstreak were seen on 3 occasions from the 05th of May to the 18th of May with the highest daily total being 2 on 2 of those occasions. Total: 5

Essex Wildlife Trust Fingringhoe Wick Nature Discovery Park

EWT Fingringhoe Wick Nature Discovery Park
Blue - all recorded sightings since 2017
Orange - 2024 recorded sightings

You guessed it, another site that I have yet to visit. It has a mosaic of open grassland, gorse heathland, reedbeds, ponds, meadows, and scrubland. Essex Wildlife Trust say that 24 of the 34 species of butterfly found in Essex have been seen at this nature reserve - these must be recorded in their own records. Green Hairstreak sightings have been recorded there every year since 2017 apart from 2018 and 2020.

EWT Fingringhoe Wick - During 2024, Green Hairstreak were seen on 3 occasions from the 04th of May to the 12th of May. Total: 3

Essex Wildlife Trust Great Holland Pits Nature Reserve

EWT Great Holland Pits Nature Reserve
Blue - all recorded sightings since 2016
Orange - 2024 recorded sightings

Surprisingly few recorded sightings of Green Hairstreak from this excellently managed reserve since the first recorded sighting in 2016 on iRecord. I do not know why this is considering the warden Bob Seago is keen on providing habitats for a number of butterfly species and the site is monitored regularly by him and Julian. I have also been there many times and have not had the good fortune of bumping into one yet, unlike White-letter and Purple Hairstreak which are relatively easy to find. They have not been recorded every year.

EWT Great Holland Pits - During 2024, Green Hairstreak were only seen on one occasion by Julian on the 04th of May. Total: 1

The Naze

The Naze
Blue - 2023 recorded sightings
Orange - 2024 recorded sightings

The Naze encompasses the mosaic of open grassland and shrubland habitats of the Essex Wildlife Trust's The Naze Nature Reserve as well as the John Weston Nature Reserve which consists of Blackthorn and Bramble thickets, rough grasslands and four ponds or ‘scrapes’. The Naze is also the gateway into Hamford Water National Nature Reserve, an area of international importance due to the number of wildfowl that visit the peninsula. It seems that Green Hairstreak sightings are a recent occurrence with recorded sightings only from 2023 and 2024. Despite that, it seems to be the place in North Essex to find Green Hairstreak with the highest total of all sites during 2024. I find it an excellent place to see butterflies and was the location for "White Day" on the 15th of September 2024 when 200+ of both Large & Small White immigrants invaded the cliffs from the continent.

The Naze - During 2024, Green Hairstreak were seen on 3 occasions from the 07th of May to the 19th of May with the highest daily total of 4 seen on the 17th of May. Total: 9

There have been less Green Hairstreak recorded sightings in the vice-county of North Essex compared to South Essex - and this maybe for a variety of reasons similar to the problems encountered throughout Essex. I would suggest that under-recording is probably a significant factor. For instance, it surprises me that there have been no recorded sightings at Hatfield Forest which seems to have ideal habitat to support a colony or two of Green Hairstreak. I am also surprised that only one has been recorded at Friday Wood and along Cherry Tree Lane for the exact same reason.

[Butterfly_Julian]

A very good read as always David, I appreciate all the work you put into these reports. As I don't own a computer, all my viewing is done though my phone which makes looking at and making best use of these web sites very hard if not near impossible alot of the time.

I was very fortunate to find a small colony, as you point out, just behind my house in 2023 and was over the moon to find it still there last year.

The Naze is a wonderful area to wander around, after a coffee and a bun at the centre. I first started going there in 2023 and expect most the butterfly recording from iRecord are from me. As your map shows the Green Hairstreak can be seen over a large area of the site, mostly as single sightings. As you know its a bit of an art finding them which iI have got better at each year.

Great Holland Pits is a real treasure of a site and has been maintained by Bob Seago to maintain and encourage a great habitat for all species of Butterfly and to get areas ready for species which don't call it home yet. The Wall, Silver-washed Fritillary and Marbled White have all been spotted there but have yet to be seen the following year.
David, as for Green Hairstreak sightings, Bob does a transect here (as well as other local sites) but i don't know how or where his records can be viewed. They will be a great deal of records for Green Hairstreak as I know his route goes right past the favourite location for the first sightings each year of this butterfly. He has been working this site for over 40 years and gets 29 species there, 30 species in 2023 and 2024 I believe.

I plan to get out locally, foot paths and the WCBS Square i record on this year to see if i can find any local colonies of the Green Hairstreak, as always to be recorded on IRecord.

Julian

[David Lazarus]

The Butterflies of Essex
2024 Year in Review

Brown Hairstreak Thecla betulae

Summary
The Brown Hairstreak is considered highly vulnerable to local extinction in the vice-county of South Essex and is extinct in North Essex. It is of the highest priority for butterfly conservation in Essex, second only to the Grizzled Skipper. The Brown Hairstreak is one of my three main target species to monitor abundance, distribution, and health of the habitats that they frequent over the next 10 years. Having said that, there has recently been great news with a third main site being found at Whitehall Plain near Chingford not far from Claybury Park. Along side a fourth site at Chigwell Row Wood, the landscape for the colonization of Brown Hairstreak has changed significantly within the north-east London area just south of Epping Forest. This means that the colony at Claybury Park is not quite as isolated as it was thought. Field surveys carried out this winter in search of ova have been very successful. Not only has there been 6 ova found at Whitehall Plain and 1 at Chigwell Row Wood, a total count of 112 ova have been found at Claybury Park, and 13 at RSPB Rainham Marshes. This supports the recorded sightings of several adult butterflies at Rainham Marshes in addition to only the second one ever being seen at Claybury Park during 2024. All-in-all then I would consider this to reflect a healthy year for the Brown Hairstreak in Essex with significant gains in abundance and distribution. A slight word of caution though. I would suggest that the Brown Hairstreak has been under recorded quite significantly in Essex and that because adults are so rare to see, knowledge of their existence in certain locations is lacking. It would not surprise me if they have been at Whitehall Plain for quite some time and that further locations within the Epping Forest area will be found with wider field surveying.

The 2024-2025 distribution of the Brown Hairstreak, limited to recorded sightings on the iRecord website, including both adult and ova, shows the current state of affairs after the field surveys carried out during the winter of 2024-25 up to the 05th of February 2025:

2024-2025 Brown Hairstreak distribution
South Essex in relation to nearest colonies

What I have tried to show in the distribution map above is how isolated the colonies of Brown Hairstreak are within South Essex. Once lost it will be hard for Brown Hairstreak to recolonize despite the distance they are known to travel. The fact that another site has been found significantly decreases that isolation and is expanding the area within the north-east of London to become more sustainable. If other existing sites can be found close by it will go a long way to avoiding local extinction and perhaps strengthen their capabilities to expand their range further. It would be great if interested parties could come together to prepare a strategy to support the Brown Hairstreak in South Essex especially when it comes to creating the necessary habitat conditions for successful breeding - suckers and last year's new growth of Blackthorn Prunus spinosa being the priority in habitats such as scrubland, woodland edge, & hedgerows with habitat patches, matrices, and corridors connecting the populations being either enhanced, restored or created. (one can only hope )

As far as abundance during 2024 is concerned, adult sightings continue to be low. We do not have sites where 40 can be seen during a bad year and 4,000 ova are laid during a good year. 100+ ova during a winter search is significant and one or two adult sightings is fortunate. So, recorded sightings of adults during 2024 is significant:

2024 Brown Hairstreak Total Abundance by Location

A grand total of 15 for the whole of Essex. But that is recorded sightings not individual butterflies which I estimate as 11 at most. Not great then, but a start. I was fortunate enough to see 3 of those individuals, and a possible 4th that I have not counted. Total abundance by date is quite interesting:

2024 Brown Hairstreak Total Abundance by Date

We are indebted to an RSPB volunteer at Rainham Marshes for this graph as he had the most recorded sightings over the year, including 3 on the same day I believe fluttering about what might be considered a Master Tree. Hopefully they will use it next year so I can have a look myself. Although I did suspect it was a possible location but did not see anything when I took a look. The fact that the season extended over three months despite only a few adults being seen, with an early arrival and one as late as the 11th of October, this makes me think we might even have 15-20 at Rainham Marshes, allowing for a little bit of optimism .

The total count of ova for the winter of 2024-2025 has provided excellent news for the conservation of the Brown Hairstreak in South Essex with a grand total of 132 ova found across 4 sites with a significant find of 112 at Claybury Park:

2024-2025 Brown Hairstreak Ova Count by Location

South Essex site locations updated

2024 Brown Hairstreak recorded sightings
South Essex site locations

Whitehall Plain

Whitehall Plain (Epping Forest), Chingford
Blue - ova found on the 04th & 11th December 2024

A new site for me, in fact I only knew about it after iRecord was updated a few days ago. I know nothing about the site except for its location and where a recent field survey found several ova with their location above. Long horn cattle graze the site which apparently is in a general favourable state with a patchwork of scrub, and open rough grassland. I look forward to visiting.

Whitehall Plain - Field surveys were carried out on the 04th & the 11th of December to count ova. Sparsely located. Total: 6 ova

Claybury Park

2024-2025 Brown Hairstreak at Claybury Park

Claybury Park is probably the main site for Brown Hairstreak in Essex. It is surprising as it is a recreational park not a nature reserve. It does though have significant areas of semi-natural habitat that favours butterflies. Not least, significant amounts of Blackthorn Prunus spinosa, other scrub areas including masses of Bramble Rubus fruticosa and rough open grassland, as well as a managed meadow and pond. To the north the land rises up into a mixed deciduous woodland with ancient Oak Quercus robur and Ash Fraxinus excelsior. There are three Ash that rise up above the canopy with an open area in front of a south-facing scallop - I think there is a high probability that it is used as a Master Tree/Congregation Area - hopefully I will know more next year. I was happy to record the one adult sighting in 2024. I do not know when the first sighting was at it does not appear to be recorded on iRecord - another one of the problems of data collection and presentation.
Recently, field studies searching for ova have found significant amounts. I was happy with 8 on Tuesday (5th) but then I saw 104 were found making 112 for 2024-2025. I was super-happy to see that one of the ova locations was just down from where I saw the female flitting between the shrub layer - if only she had settled (just for a little bit) so I could have got my happy snap.

Claybury Park - One adult (female) seen on the 18th of August. Ova counts took place on the 17th & 29th of January, and the 5th of February. Total: 1 adult; 112 ova

Chigwell Row Wood

Chigwell Row Wood

I have not visited this site where one ova was found last year.

Chigwell Row Wood - One ova found on the 21st of October. Total: 1 ova

RSPB Rainham Marshes

2024-2025 Brown Hairstreak at RSPB Rainham Marshes

Probably the second most important site for Brown Hairstreak in Essex, it is quite a distance from any other colony which means it is super-vulnerable to extinction if conservation work and habitat management fails. The paucity of records in the public domain, that is to say recorded on iRecord, is not only disappointing but means I cannot analyse or evaluate the data or identify trends. All the records available are from 2024. The fact that the first sighting was posted on Facebook with beautiful photographs meant that about 20 people travelling from far distances visited Rainham Marshes on the 14th of July and on the days following looking for the male Brown Hairstreak that appeared in the car park. I wondered why people would bother considering they are more likely to see them in the sites to the south of the river. Needless to say it was Bill, the RSPB volunteer who provided us with consistent sightings throughout the year - which we should be very grateful for. The field surveys carried out in February 2025 counted 13 ova which is no more than okay, I would suggest. Unfortunately, the management for Brown Hairstreak does not appear conducive to supporting conservation aims as much of the Blackthorn in the car park has been cut back this winter.

Rainham Marshes - Adults were seen on 10 occasions from the 14th of July to the 11th of October with the highest daily total being 3 on two occasions, the 06th and the 22nd of September. Total: 14 (10 or 11 individuals); 13 ova

Brown Hairstreak male
Rainham Marshes 14/07/2024
Copyright: Ian Plume

Highlights
For me personally, seeing three adults fluttering around quite close to me, with one teasing me by flying a metre in front of me but disappearing instead of behaving respectfully. The fact that one of them was at Claybury Park was amazing and cause for celebration. And another that was not in the car park at Rainham Marshes but along the Rainham-Purfleet Path was the most significant find as I believe they use the Blackthorn scrub within the rough grassland on the reserve side of the path - but no one has found ova there yet. Unfortunately I could not find any on 14.02.2025.
For the Brown Hairstreak, the highlight is definitely the quantity of ova that has been found at Claybury Park, as well as finding ova at a new site - Whitehall Plain, meaning that it is highly likely they had a fantastic year and have maybe increased their abundance and distribution within Essex. The lack of ova found at Rainham Marshes is sad and I am frustrated about the amount of Blackthorn that has been cut back this winter especially around the car park. Let’s hope it does not significantly impact the ability of the Brown Hairstreak to survive.

Disappointments
Sorry to hark on about this, but I did not manage to get a photograph of a Brown Hairstreak during 2024

[David Lazarus]

I was very fortunate to find a small colony, as you point out, just behind my house in 2023 and was over the moon to find it still there last year.

The Naze is a wonderful area to wander around, after a coffee and a bun at the centre. I first started going there in 2023 and expect most the butterfly recording from iRecord are from me. As your map shows the Green Hairstreak can be seen over a large area of the site, mostly as single sightings. As you know its a bit of an art finding them which iI have got better at each year.

Great Holland Pits is a real treasure of a site and has been maintained by Bob Seago to maintain and encourage a great habitat for all species of Butterfly and to get areas ready for species which don't call it home yet. The Wall, Silver-washed Fritillary and Marbled White have all been spotted there but have yet to be seen the following year.
David, as for Green Hairstreak sightings, Bob does a transect here (as well as other local sites) but i don't know how or where his records can be viewed. They will be a great deal of records for Green Hairstreak as I know his route goes right past the favourite location for the first sightings each year of this butterfly. He has been working this site for over 40 years and gets 29 species there, 30 species in 2023 and 2024 I believe.

Thank you so much for adding your thoughts. I know you do a great deal to support butterfly conservation by monitoring species and abundance in the Naze/Holland Haven area and further afield. It is always good to see your records and Bob's on iRecord so I can better understand what is going on up there. According to Bob's transect records he has only seen Green Hairstreak on 5 occasions at Great Holland Pits in 2015, twice in 2021, and twice in 2023 - a total of 8. So they are there but, as you say, hard to find unless they pop out unexpectedly when brushing up against a hawthorn or something (so I hear). I will practice tapping hawthorn this April and May in my pursuit of this lovely butterfly.

[David Lazarus]

The Butterflies of Essex
2024 Year in Review

Purple Hairstreak Favonius quercus

Summary
The Purple Hairstreak is of Least Concern in the vice-counties of North and South Essex, and is considered the lowest priority when it comes to butterfly conservation. It has been described as common and widespread within the whole of Essex, although colonial. It is certainly the most common of all the Hairstreaks by some margin. It is also said to be the most common of all the UK's butterflies in oak woodland, especially managed oak woodland. This would imply that Essex has numerous colonies because of the quantity of both ancient oaks and mixed deciduous woodland on clay soils, which generally retain moisture conducive to the health of both of the native oaks, Pedunculate Oak Quercus robur and Sessile Oak Quercus petraea. Not only are they found in most, if not all, of the remaining woodland areas, habitats where they can be found include hedgerows [although these have diminished since the 1960s with the change to intensive farming with larger fields], parks, and standalone specimens throughout the county in both countryside and urban settings. Unfortunately, not only have they been lost during the removal of miles of hedgerows and the continued fragmentation of our woodlands, many ancient specimens are now also being cut down and removed for housing development, as well as being blamed for subsidence. Despite the quantity of oak in the county, the Purple Hairstreak must be the most under-recorded of all the butterflies in Essex. This is not only because of the lack of experienced butterfly recorders, but because most existing recorders choose to carry out daytime transects counting within 5 metre square boxes which would rule out sightings of the Purple Hairstreak which spends most of its time high up in the canopy. To counter this, Butterfly Conservation have introduced a new transect specifically to count Purple Hairstreak between 6 and 8 o'clock. According to the data available on the iRecord website, there were only 199 recorded sightings of Purple Hairstreak during 2024 [of which 90 were my own] and no one except for myself took on the responsibility of walking a Purple Hairstreak transect within Essex during the past couple of years. I would advise those who are reading this and live in Essex, especially in the Epping Forest, Hatfield Forest, Danbury Ridge, Writtle Forest, and those woodlands in the south Essex and north-west Essex areas to consider taking up the option to walk a Purple Hairstreak transect this year [2025]. It is the only way we will gain better knowledge about the abundance and distribution of this elusive but common butterfly. Also, it is a wonderful sight to behold during an evening stroll.

Understandably the data is not comprehensive because of the aforementioned explanation. The 2024 distribution of the Purple Hairstreak, limited to recorded sightings on the Butterflies for the New Millennium Online website, provides us with some sort of clue where colonies exist but is lacking so much data that the map is of limited use and certainly does not show the "distribution" of the Purple Hairstreak within Essex:

2024 distribution of Purple Hairstreak within Essex
Source: Butterflies for the New Millennium Online

The map showing recorded sightings for the past 10 years is not much better but at least begins to provide us with a distribution closely linked to the wooded areas of Essex, but once again is clearly not providing us with the true distribution of Purple Hairstreak within the county of Essex and north-east London:

2014-2024 distribution of Purple Hairstreak within Essex
Source: Butterflies for the New Millennium Online

Interestingly, the above map is very similar to that published in Corke, D., & Goodey, B., 1997 The Butterflies of Essex Lopinga Books. Not much has changed in the past quarter of a century to monitor the abundance and distribution of this butterfly. If we had the numbers, it would be useful to have a comprehensive and systematic count of as many tetrads covering oak woodland and hedgerows across the whole of Essex and the north-east of London during July of 2025 or 2026. I do not know how we can even give an informed estimate of the trends in abundance and distribution without one despite figures being published in The State of the Uk's Butterflies xxxx Report which admittedly covers the whole of the UK - and has much more data than I to analyse and evaluate. I am actually focused on local knowledge and butterfly conservation within the county that I reside. The data available in the public domain restricts the ability to do this unfortunately, hence my 10 year project.

My own recorded sightings map for 2024 is not much different from the distribution map above:

2024 my recorded sightings of Purple Hairstreak within Essex

My own recorded sightings of Purple Hairstreak, apart from locally, are limited by the time of day I carry out my site visits and because Purple Hairstreak is not one of my target species. Generally I only see them in places like Hatfield Forest, Epping Forest, Friday Wood, and the Danbury Ridge Nature Reserves when I am searching for the premium woodland species that I am targeting. Despite this, the following are my abundance during 2024 tables and graphs for recorded sightings of Purple Hairstreak within Essex:

2024 Purple Hairstreak Abundance by Location

Obviously, totals are weighted towards my local patch where I walk my Purple Hairstreak transect. It just shows what can be achieved if such transects could be established throughout Essex.

The 2024 abundance by date shows the peak count between mid to late-July in line with published flight periods:

2024 Purple Hairstreak Abundance by Date

What I can say about these figures is that on the one hand I can say that 159 is quite a good count considering. However, just to put this into perspective, last year when I was at Epping Forest one evening I managed to count 62 within an hour within a very small area. During 2024, I never saw more than 6 on one oak when 20 or so during aerial displays is not uncommon on trees during a good year let alone the 100s some people see if they are in the right place at the right time. Somewhere like Hatfield Forest, for instance, I would expect Purple Hairstreak to be in their 100s to possibly total 1000 plus for the whole site during their flight period. And similarly, I would expect the same to occur at the other prime sites for butterflies in mixed deciduous woodlands throughout the county.

South Essex

The following locations are where sightings of Purple Hairstreak were recorded by me during 2024 within South Essex:

2024 Purple Hairstreak recorded sightings
South Essex site locations

Meadgate Park & Meadgate Fields Open Space

Meadgate Park

The maps are not great because of the annoying transect tetrads which obscure the actual location of the tree. Meadgate Park has 6 mature Pedunculate Oaks Quercus robur along about a 200 metre border amongst mixed scrub. There are also trees of various ages on which I have seen them. I have seen Purple Hairstreak come down quite low but have never seen one nectaring on the abundant bramble flowers. I must have walked past these oaks numerous times without having the required knowledge to realise that each oak had a colony of Purple Hairstreak in them - much to my surprise when I finally looked up.

Meadgate Park - Purple Hairstreak were seen on 15 occasions with the first sighting on the 26th of June, and the final sighting on the 04th of August - a comparatively short flight period, although I was focusing on other searches from mid-August into September. The highest daily total was 13 on the 13th of July. Total: 59

Meadgate Fields Open Space

Just to the east of the park the line of oaks continues along a bridleway and into the main wooded area adjacent to the meadow and bordering the glade with mature Ash Fraxinus excelsior. There are also a couple in the adjacent gardens.

Meadgate Fields Open Space - Purple Hairstreak were seen on 11 occasions from the 26th of June to the 18th of August with the highest daily total of 15 occurring on 2 occasions, the 13th of July and during the following week on the 20th of July. The highest count for the combined locations along the transect was 25 on the 20th of July. Total: 66

I did manage to photograph a female at the meadow in Meadgate Fields Open Space in early August as she came down to lay ova on quite a small oak - perhaps 10-15 years old only - maybe 8 metres high. She came down ovipositing to about 2.5-3 metres, low enough to take a few shots with my iPhone.

Purple Hairstreak female
Meadgate Fields Open Space

Danbury Ridge Nature Reserves & Danbury Common

Danbury Ridge Nature Reserves & Danbury Common

As I have already stressed, the following sites were not visited to search for Purple Hairstreak. I have uploaded a map of the whole area encompassing the Danbury Ridge Nature Reserves from the River Chelmer to the north down to the southern most tip of Danbury Common to show how much of the area contains ancient wet woodland. No one has surveyed the area for Purple Hairstreak. I have no doubt that they exist in all of these wooded areas and their numbers will definitely be in the 100s if not 1000s. My total of 8 does not provide the data required to ascertain the true health of the colonies that exist in this area.

Lingwood Common - Purple Hairstreak were seen on 5 occasions from the 08th of July to the 11th of August with 2 being the most on the 26th of July. Total: 6
Little Baddow Heath - a single Purple Hairstreak was seen on the 05th of August. Total: 1
Danbury Common - a single Purple Hairstreak was seen on the 19th of August. Total: 1

Purple Hairstreak female
Danbury Common 19/08/2024

Hockley Woods

Hockley Woods

I do not think anyone goes to Hockley Woods to monitor Purple Hairstreak numbers despite the woods having ample oak and ash within quite a large area. I only saw a couple on two different trees when visiting to monitor Heath Fritillary numbers - still there as the sun was going down. The combined woods in the Hockley, Rayleigh, Hadleigh, and Benfleet area must host numerous colonies of Purple Hairstreak - again, in their 100s.

Hockley Woods - two Purple Hairstreak were seen on a single occasion, the 28th of June. Total: 2

One Tree Hill - Northlands Wood

One Tree Hill - Northlands Wood

This is another area with insufficient data collected to give us accurate knowledge about the health of Purple Hairstreak colonies in this area which is ideal for hosting Purple Hairstreak in their 100s over a very large area of woodland patches. Only a small part of this woodland patch network is shown on the above map.

Northlands Wood - a single Purple Hairstreak was seen on the 13th of August. Total: 1

North Essex

The following locations are where sightings of Purple Hairstreak were recorded by me during 2024 within North Essex:

2024 Purple Hairstreak recorded sightings
North Essex site locations

Hatfield Forest

Hatfield Forest

Hatfield Forest is the foremost site to search for woodland species of butterflies in North Essex - probably the whole of Essex, I think. Despite this no one but myself has recorded a sighting of a Purple Hairstreak during 2024 including those who go there to monitor Purple Emperor. In the last 25 years, there have been 18 recorded sightings on the iRecord database. 4 of those were mine from 2024. I think you can start to understand the problem we have here in Essex.

Hatfield Forest - Purple Hairstreak were seen on 2 occasions, the 19th of July and the 12th of August. Total: 4

Friday Wood & Cherry Tree Lane

Friday Wood & Cherry Tree Lane

I would consider the woods within the Friday Wood area and along the hedgerows of Cherry Tree Lane to be an even better place to monitor Purple Hairstreak numbers, particularly in North Essex. I saw them when looking for White-letter Hairstreak, annoyingly flitting around on the Field Elm Ulmus minor hedgerows. In this case there have been 18 recorded sightings in the past quarter of a century, half of them my own during 2024.

Friday Wood - Purple Hairstreak were seen on 2 occasions, the 11th & 18th of July with the highest daily total of 9 on the 11th. Total: 11
Cherry Tree Lane - Purple Hairstreak were seen on the 18th only. Total: 6
Plus, a single sighting at Charlotte's Grove. Total: 1

Great Holland Pits

Great Holland Pits

Another place that I would expect to have colonies of Purple Hairstreak, perhaps not in as great a number as the other sites. 22 recorded sightings since 2013, with 8 of those during 2024, with a total of 33 individuals seen in 2024. 29 of those individuals were seen by Julian Butterfly_Julian.

Great Holland Pits - a single sighting of a Purple Hairstreak on the 18th of July. Total: 1

Highlights
Not many highlights really, mostly disappointments as expressed above. However, it was pleasing to see Purple Hairstreak flitting to and fro above the oaks in my local park and to see them reasonably close up on some occasions. The unexpected sight of a female Purple Hairstreak when I was passing a patch of brambles she was on was a joy. It was the first and only time I have been up close to a Purple Hairstreak with their wings open although I have seen them basking in the canopy using my binoculars. Not only that, I managed to get some nice photographs even though she was a bit tatty.

[essexbutterflyer]

Hatfield Forest is the foremost site to search for woodland species of butterflies in North Essex - probably the whole of Essex, I think. Despite this no one but myself has recorded a sighting of a Purple Hairstreak during 2024 including those who go there to monitor Purple Emperor. In the last 25 years, there have been 18 recorded sightings on the iRecord database. 4 of those were mine from 2024. I think you can start to understand the problem we have here in Essex.

Hatfield Forest - Purple Hairstreak were seen on 2 occasions, the 19th of July and the 12th of August. Total: 4

I agree very much David. There is a lot of under-recording... perhaps the value of iRecord is not well understood in the wider community? I also feel like it is easy to neglect the recording of some commoner species, especially if they are at a site with rare ones...

[essexbuzzard]

Seconded. The distribution maps in this species, as well as many other common butterflies such as Orange Tips, show the location of observers and recorders, not of butterflies. If there were enough observers, I expect almost every tetrad in the county would eventually produce a Purple Hairstreak sighting. Even if every mature oak in Essex had just one adult living on it, the total population would be, and probably is, colossal.