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Hi David.

Overall, I have not found the Brimstone to be particularly common in the county, due to a lack of foodplant. But there are pockets of high population here and there. One is, as you say, the Danbury area, where Alder Buckthorn is common . Another is the Grays area, where Purging Buckthorn is the foodplant, and is abundant on the chalk in that area.

Despite low numbers overall, the Alder Buckthorn I planted in my garden is used every year, although the sparrows seem to find the caterpillars much to their liking!

If you’re going looking for Brimstones next summer, I’d probably try late July or early August. If the weather is good, as it was last year, the adults may go into hibernation just two or three weeks after emergence. Certainly last year, most seemed to have gone by mid August.

Thoroughly enjoying your reports, David. The demise of Grizzled Skippers in the county is of great sadness. They were still fairly common at several sites across Langdon as recently as the mid 1990’s .It’s been several years since I’ve seen them at Johnson’s. Although some conservation work was done, it has probably just delayed the inevitable, sadly.

essexbuzzard wrote: ↑Fri Jan 10, 2025 11:04 pm Overall, I have not found the Brimstone to be particularly common in the county, due to a lack of foodplant. But there are pockets of high population here and there. One is, as you say, the Danbury area, where Alder Buckthorn is common . Another is the Grays area, where Purging Buckthorn is the foodplant, and is abundant on the chalk in that area.

Thank you for your comments, Mark, much appreciated. You have reminded me of the importance of fact checking. To make a mistake about butterfly ecology and phenology is one thing, and would not be a surprise to me as I am learning to write about butterflies, but I regard myself as a bit of an ecologist and know quite a bit about plants - so to get the two buckthorn the wrong way around, not for the first time I must add, is very embarrassing for me . You would have thought I would remember as I have planted Alder Buckthorn in the gardens here, and Essex hardly has any chalk landscapes. Oh well, hopefully I will remember now despite memory issues

essexbuzzard wrote: ↑Fri Jan 10, 2025 11:04 pm Thoroughly enjoying your reports, David. The demise of Grizzled Skippers in the county is of great sadness. They were still fairly common at several sites across Langdon as recently as the mid 1990’s .It’s been several years since I’ve seen them at Johnson’s. Although some conservation work was done, it has probably just delayed the inevitable, sadly.

The Butterflies of Essex
2024 Year in Review

Large White Pieris brassicae

Summary
The Large White is of least concern in the vice-counties of North & South Essex, and it is a low priority for butterfly conservation within Essex. Indeed, Large White is regarded as a reasonably widespread and common butterfly in Essex although numbers are well below those I experienced as a child. Despite low recorded sightings of the Spring brood, Large White came 7th of the 34 species seen in Essex with a total of 888 recorded sightings. I must admit that this total surprises me as I cannot recall seeing Large White in any great numbers until September. Indeed, I was probably feeling disappointed and regarding 2024 as a bad year for Large White. Sometimes, I think we forget that numbers of the resident population can be augmented by migrants, and this was definitely the case when an influx of migrants swept over the Essex Coastline during the second week of September producing a quarter of all the recorded sightings I had in 2024 within a few days.

The 2024 distribution of the Large White, limited to recorded sightings on the Butterflies for the New Millennium Online website, shows a widespread distribution across much of Essex:
The recorded sightings for the last 10 years shows a more complete distribution, although this does not necessarily confirm that 2024 was a bad year for Large White but the feeling would be that distribution and abundance was indeed down - particularly true for the Spring brood like many have commented on over the whole of the UK:
As far as my own recorded sightings are concerned, distribution indicates that I saw most within mid-Essex and the Essex coast, particularly along the North-east coastline near Walton-on-the-Naze:
And the abundance during 2024 according to my recorded sightings at these site locations confirms this:
This shows that the immigrant numbers both at The Naze & the North-east coast of Essex, and a few days after at Benfleet Downs and along the sea wall at East Tilbury, far surpassed all other locations, with most of the other sightings being locally within the floodplain of the River Chelmer, with notable numbers on particular site visits to Hockley Woods and Lingwood Common late in the season.
As previously mentioned, most of the recorded sightings happened later on in the year with a steady stream of sightings, never more than single figures, from April until the first of the Summer brood, with numbers okay in August before shooting up in the first two weeks of September. The first sighting was locally at Baddow Hall Park & Baddow Meads on the 08th of April. Single figures were recorded throughout April, May, June & July. The first time I saw double figures during a site visit was when I visited Hockley Woods on the 15th August when 26 were seen within the fields along its southern edge. The summer brood during late August into the first week of September produced reasonable numbers everywhere I went. Then "White Day" on the 15th of September accounted for 189 of my annual recordings when the cliffs of Walton-on-the-Naze were covered in whites from the continent. The final sighting occurred on the coast at St. Lawrence on the 11th of October.

Highlights
To experience a day like "White Day" on a trip to Walton-on-the-Naze was something unexpected and it made me very happy as it seems to be a lot rarer these days to see large numbers of the same species in one place at the same time. However, it was probably the case that the September numbers hide the fact that Spring numbers were poor and the Summer brood was not much better. Locally, it never seemed as good as the numbers would suggest but I have to accept that 306 is okay.

The Butterflies of Essex 2024 Year in Review continued

South Essex

The following locations are where sightings of Large White were recorded by me during 2024 within South Essex:
Baddow Meads & Meadgate
There was a consistent flow of visitors to the gardens I manage, with a good overall number of 90 nectaring on ornamental flowers, such as buddleja and lavender, as well as in the wildflower meadows where Field Scabious Knautia arvensis is popular. There was also a steady flow of Large White flying along the scrub boundary of the local park, along the bridleway, and in the rough grassland of the meadows at Meadgate Field Open Space. Baddow Meads is a stronghold for the other whites with numbers of Large White reasonably good during 2024. It was a long season from the first week of April to the first week of October, but there was never more than a steady flow until 50 sightings were recorded during the first week of September.

Garden on Meadgate Avenue - Large White were seen on 40 occasions, with the first sighting on the 01st of May, and the last one on the 08th of October, with the most seen on any one day on 03rd September when 12 were seen. Total: 90
Meadgate Park - Large White were seen on 25 occasions, with the first sighting on the 18th of April, and the final one on the 26th of September, with the most being 7 on the 27th of August. Total: 36
Meadgate Fields Open Space - Large White seen on 29 occasions with the first sighting on the 11th of April, and the final sighting on the 29th of September. The most on any one day was 7 on the 09th of August. Total: 59
Baddow Meads - Large White were seen on 35 occasions, with the first sighting on the 08th of April, and the final sighting was on the 21st of September, with 14 seen on the 08th of September being the most on any one day. Total: 67
Other local sightings accounted for 5 to make an overall total of 257 in the Meadgate area around where I live.
Lingwood Common & Danbury Ridge
The field margin to the south of Lingwood Common provided useful nectar-rich flowers, and they were seen flying up and down the scrub along the ditch. Surprisingly, few were seen anywhere else in Danbury with numbers at Danbury Common particularly disappointing although I did not visit there often when they were flying locally, but there was only one seen at their peak on a visit in September. Another 41 to add to those seen locally in mid-Essex.

Lingwood Common - Large White were seen on 22 occasions between the 08th of July and the 11th of September with most seen during July, the most being 15 on the 08th July. Total 38
Little Baddow Heath - 2 only seen on the 14th of July. Total 2
Danbury Common - only a single Large White seen on the 11th September. Total 1

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Wallasea Island and the sea wall along the River Crouch estuary
Wallasea Island is an RSPB Site of Special Scientific Interest managed mostly for waterfowl with the unimproved grasslands, and forb-rich meadows left long providing ideal habitat for a diverse range of insects, including a good selection of butterflies. It is a good place to see migrants, with Painted Lady, Red Admiral, Clouded Yellow, and the Whites flying in from the continent common visitors. One of the better places to see butterflies in Essex, an RSPB volunteer has collected, analysed, and evaluated data over a number of years to present valuable trends for the island.

Wallasea Island - Large White were seen on 3 visits during late summer with 15 seen on the 07th of September being the highlight. Total: 24
Burnham-on-Crouch - 6 seen on the 26th of August. Total: 6
Also, 2 seen at Marsh Farm & 1 at Battlebridge. Overall Total: 33
Hockley Woods
Similar to Lingwood Common, Hockley Woods has wide forb-rich field verges to the South-west and Eastern edges of the wood, and fields of clover and alfalfa which attracted a large number of whites on one particular visit.

Hockley Woods - Large White were seen on 4 site visits from the 24th of May to the 15th of August, on which day 26 were seen nectaring on Alfalfa Medicago sativa. Total: 40

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Benfleet Downs
Benfleet Downs has a mosaic of habitats including sloping south-facing forb-rich rough grasslands, scrub, and wooded areas with wide paths flowing through them. The landscape attracts healthy numbers of a good variety of butterflies which can be seen throughout the seasons - particularly good for hairstreaks and the grassland species, with high numbers of 3rd brood Wall during 2024.

Benfleet Downs - Large White were seen on 2 visits with the highlight being the 17th of September during the influx of migrants when 39 were seen. Total: 45
One Tree Hill - Johnson's Meadows

Not particularly good for Large White, the lowest number of all the common whites were seen.

One Tree Hill - Johnson's Meadows - Large White were seen on 4 occasions from the 25th of June to the 17th of September. Total: 20
Thames Estuary Path near East Tilbury, EWT Thameside Nature Discovery Park, & Coalhouse Fort Grasslands SSSI
Large White were a component of the butterfly profile along the sea wall when this butterfly haven was discovered on the 19th of September after the influx of migrants. Also, on the same day a few more were seen on a circuit of the nearby nature reserves.

Thames Estuary Path - Large White were seen on 3 occasions during the last two weeks of September. Total: 57
EWT Thameside Nature Discovery Path - Total: 7
Coalhouse Fort Grasslands - Total: 1

The Butterflies of Essex 2024 Year in Review
South Essex - Thames Estuary Path continued
Rainham Marshes

Large White appeared on 4 occasions but numbers were disappointing. Total: 9
Bradwell Waterside & St. Lawrence

Some of the last Large White were seen along the forb-rich sloping, south facing grassland banks of the Essex Saltmarsh Coast sea wall in October. Total: 4

The Butterflies of Essex 2024 Year in Review continued

North Essex

The following locations are where sightings of Large White were recorded by me during 2024 within North Essex:
Hatfield Forest
Large White could be found flying up and down the woodland rides, mostly in ones and twos, but in sufficient numbers on the 19th of July to be considered as one of the main components of the ride's butterfly profile.

Hatfield Forest - Large White were seen on 4 occasions between the 26th of June and the 18th of September with the greatest number on the 19th of July with 24. Total: 32

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Chelmer Valley, Admirals Park, & Garden on Chignal Road

More local sightings within Chelmsford, mostly ones and twos along the rivers, but also at my mother's garden which I manage with a mix of ornamental and native planting, including a wooded area and open grassland.

Garden on Chignal Road - Large White were seen on 8 occasions with the first seen on the 25th of April, and the final one seen on the 24th of September, with 17 seen during the final week of August to the end of September. There was also 28 ova laid on Nasturtium Tropaeolum majus, with 20 or so larva.
Admirals Park LNR - a total of 7 were seen along the River Can; & 4 more north along the Chelmer Valley NR to Little Waltham Meadows NR.
Great Notley Country Park
Great Notley Country Park is a recreational playground with a desire to improve its ecological benefits with an interest in enhancing the habitats to attract butterflies. It has a varied mosaic of habitats with open grassland areas, including rough long grass meadows and forb-rich meadows, as well as wooded areas, long rides, and lakes, as well as a south-facing slope with mixed scrub and grassland. Unfortunately, there have been very few recorded sightings of butterflies so far but it has the potential to be a place to visit to see butterflies in the future.

Great Notley Country Park - Large White were seen on one visit with 25 seen on the 06th of September. Total: 25

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Friday Wood & Cherry Tree Lane

13 were seen on the two visits during July, which was a disappointing total. I am hoping numbers had improved during late summer into September when I did not visit.

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Great Holland Pits and Holland Haven Marshes
Great Holland Pits is another location within North Essex that I would expect to see higher numbers, especially given the proximity to the North-west Essex coastline. Holland Haven Marshes has scrub areas and open rough grassland adjacent to a large area of marshland.

Great Holland Pits - Large White were seen on four occasions between the 12th April and the 26th of August with the last visit producing the most sightings of 20. Total: 24
Holland Haven Marshes - One visit on the 26th of August. Total: 10
Walton-on-the Naze promenade, The Naze, & Walton Mere
The Naze is a cliff front nature reserve along the North-west Essex coastline with scrub and open grassland providing suitable habitat for butterflies. It has garden escapees, Buddleja Buddleja davidii, naturalising on the cliffs which attracted 200+ each of Small and Large White immigrants to stop off to nectar on the 15th of September.

The Naze - Large White in great numbers on "White Day". Total 149
Walton-on-the-Naze promenade & Walton Mere along the sea wall. Total: 40

The Butterflies of Essex
2024 Year in Review

Small White Pieris rapae

Summary
The Small White is one of our most common butterflies, it is of least concern in Essex being widespread, and is regarded as low priority when it comes to butterfly conservation. However, like most of the 'common' butterfly species in Essex, abundance is down by a quarter since I was a child, although in the last 10 years there has been a little rise. Now, Small White numbers are thought to be stable in abundance and occurrence across Essex. I think they are still regarded as pests here, as much of the landscape is agricultural, and they are victims of pesticide use. Small White ranked 3rd (around about = 2nd with Green-veined White) in my recorded sightings for 2024, reflecting the habitats in proximity to where I live, and the amount of time I spent walking the Essex coastline during late Summer and early Autumn. As with the case of the Large White, numbers were boosted by the influx of migrants from the continent during the first two weeks of September.

The 2024 distribution of the Small White, limited to recorded sightings on the Butterflies for the New Millennium Online website, shows a similar distribution to the Large White, with much of the sightings being recorded in mid-Essex, East London, and the Essex coastline, particularly in the North-west of Essex:
As far as the last 10 years is concerned Small White has been recorded over most of Essex except in the areas where recorded sightings are non-existent for all butterfly species, for unknown reasons - maybe agricultural land with low population density:
My recorded sightings, as already mentioned, tended to be in my local area within Chelmsford and mid-Essex, as well as along the estuaries and Essex coastline when I was searching for other species:
And the abundance during 2024 according to my recorded sightings at these locations confirms this:
Once again, like the Large White, large numbers were recorded during September with another 200+ seen along the cliffs of Walton-on-the-Naze and The Naze on the 15th of September, as well as a few days later within Benfleet Downs and along the Thames Estuary sea wall at East Tilbury, Canvey Island, & Two Tree Island, as well as steady numbers at Wallasea Island and along the River Crouch & Dengie Peninsula. As the table shows, Chelmsford and mid-Essex accounted for 423, about a third of the total number.

The abundance over time, by date of the site visit, clearly shows that numbers were not great for most of the Small White's flight period, only really being seen in good numbers from the last week of August, peaking during the middle of September, with a few being seen into October:
Highlights
Most of my recorded sightings were later on during the year, and I had an especially happy time watching them along the Essex Saltmarsh Coast when searching for Wall. The Naze on "White Day" was amazing, and this carried on at my visits to the Thames Estuary Path near East Tilbury. My local patch is a great place to see all the whites, 400 plus being a good number, but this felt a lot lower than previous years probably because most of these sightings were during the time of the year when numbers were low. I really could not tell when the Spring Brood became the Summer Brood, or the period between, and I did not walk the banks of the River Chelmer like I usually do to see large numbers later in the year. I am not sure many, if any, of the migrants reached Chelmsford, so I should feel lucky that there were 400 plus, with a remarkable 108 recorded sightings within the gardens I manage at my home. It honestly did not feel like that - if someone had asked me without referring to my notes, I would have said under 50.

The Butterflies of Essex 2024 Year in Review continued

South Essex

The following locations are where sightings of Small White were recorded by me during 2024 within South Essex:
Baddow Meads, Chelmer Valley, & River Can
Small White are a common sight along the River Chelmer both north through Chelmer Valley and east towards Sandford Lock. During 2024 I spent less time walking the rivers, where numbers tend to be larger during the Summer brood and into autumn. Despite that numbers were good, with 195 along the River Chelmer and within the floodplain of Baddow Meads, as well as a further 172 in the Meadgate area including the gardens I manage. Like most places in Essex, numbers were steady with double figures only seen in September.

Garden on Meadgate Avenue - Small White were seen on 54 occasions, with the first sighting as early as the 12th of March - which became my first photograph of a butterfly in 2024 - and the last one was seen on the 02nd of October, nearly 7 months later. The most I saw on any one day was the 11 that visited on the 21st of September. Total: 108
Meadgate Park - Small White were seen on 27 occasions with the first one seen in the local park on the 20th of March, and the final one on the 04th of October, never more than 2 or 3 at a time. Total: 40
Meadgate Fields Open Space - Small White were only seen on 8 occasions from the 18th of April until the 21st of September. Total: 23
Baddow Meads - Small White were seen on 28 occasions with the first seen on the 01st of April, and the final one on the 21st of September, with 89 of the total seen within September [58%]. Total: 153
Another 31 were seen along the River Chelmer, with 25 of those on one walk along the riverbank on 08th of August - I would have probably seen 150-200 from the start of August until October if I had walked the riverbanks regularly. 36 were seen along the River Can, west of Chelmsford and in my mother's garden [North Essex].
Lingwood Common, Danbury Ridge Nature Reserves, & Danbury Common
Despite the proximity to the River Chelmer floodplain, with the river flowing past Danbury and Little Baddow at Paper Mill Lock, numbers are low with no sightings within the Danbury Ridge Nature Reserves, with a few seen at Lingwood Common and Danbury Common. I am presuming numbers are restricted due to a lack of larval food sources. All the same, give the abundance seen a few miles away it is surprising.

Lingwood Common - Small White were seen on 7 occasions between the 20th of May and the 11th of September. Total: 15
Danbury Common - Small White were seen on 3 occasions between the 10th of May and the 11th of September. Total: 5
Maldon Wick

The Essex Wildlife nature reserve at Maldon Wick was also a poor location for seeing Small White. Total: 4

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Bradwell Waterside, St. Lawrence, & the Dengie Peninsula
The sea wall along the Essex Saltmarsh Coast turned out to be a good place to see Small White nectaring on late-season nectar sources, especially Prickly Ox-tongue Helminthotheca echioides. This included the last sightings of Small White during 2024.

Bradwell Waterside & the Dengie Peninsula - visited only once on the 07th of October. Total: 18
St. Lawrence, Ramsey Marsh, & the River Blackwater - two occasions on the 11th & 16th of October. Total: 14
Wallasea Island & Burnham-on-Crouch
Another coastal location, Wallasea Island has habitats, including larval food sources & late-season nectar sources, that support healthy numbers of Small White with one of the highest totals seen on one visit throughout Essex locations.

Wallasea Island - Small White were seen on 3 occasions on the 29th of August, when 41 were seen, as well as the 07th & 14th of September. Total: 77
Burnham-on-Crouch sea wall & Holliwell Point - two visits on the 27th of August when 21 were seen with one more at Holliwell Point on the 07th of October. Total: 22
With another 9 at Fen Creek, 3 at Marsh Farm, 3 at Hullbridge, and a further 2 along sea wall of the River Crouch.

Hockley Woods & the South Essex woods
Small White were only seen in the fields around the woods where wildflower meadows have been created, and a field of Alfalfa Medicago sativa created a late summer nectar source for whites. No Small White were seen at either Pound Wood or Hadleigh Great Wood.

Hockley Woods - Small White were seen on 4 occasions between the 24th of May and the 15th of August, the day most were seen [14]. Total: 26
Benfleet Downs, Canvey Island, & Two Tree Island, and One Tree Hill
Numbers of Small White were good at these locations in the South-east of Essex particularly in late summer and when the immigrants boosted the numbers in early September. All these location provided late summer nectar sources, and being coastal sites they attracted those flying in from the continent. A visit to Benfleet Downs a couple of days after "White Day" at The Naze provided another 50 sightings. Two Tree Island summer brood were in good numbers with sightings being one of the highest for one day. Further inland, One Tree Hill, Johnson's Meadows were relatively quiet.

Benfleet Downs - Small White were seen on a couple of visits on the 28th of August & the 17th of September. Total: 63
Canvey Wick & Canvey Island Loop - Small White were seen on the 30th of August. Total: 38
Two Tree Island - Small White were seen on the 28th of August. Total: 61
One Tree Hill - Small White were only seen in single numbers on 5 occasions between the 01st of May and the 17th of September, the influx of migrants not reaching Langdon Hills on that day. Total: 14
Thames Estuary Path near East Tilbury, EWT Thameside Nature Discovery Park, & SSSI Grassland Nature Reserve - Coalhouse Fort
Small White formed an important component of the butterfly profile along the sea wall at East Tilbury, and good numbers were seen at the Essex Wildlife Trust's Thameside Nature Discovery Park which is being developed on the site of the old Mucking Marshes Landfill. This location is only going to get better for butterflies with open grasslands and scrub areas covering a large area to compliment the forb-rich grasslands on the South-west facing sloping banks along the Thames Estuary Path sea wall. Large numbers were seen on each visit at the end of the summer and after the influx of migrants. The 19th of September was the second largest daily total recorded after The Naze with 120.

Thames Estuary Path near East Tilbury - Small White were seen on 3 occasions during September, the 19th, 20th, & 28th with 2 of the highest daily totals recorded. Total: 149
EWT Thameside Nature Discovery Park - Small White were seen on the 19th & 28th of September. Total: 55
SSSI Grasslands Nature Reserve - Coalhouse Fort - one late afternoon visit on the 19th of September. Total: 4
Rainham Marshes
Small White were in good numbers around the car park in the rough grassland verges, as well as along the sea wall slopes and within the scrubland-grassland areas of the reserve.

The Butterflies of Essex 2024 Year in Review continued

North Essex

The following locations are where sightings of Small White were recorded by me during 2024 within North Essex:
Hatfield Forest

Surprisingly, very few Small White were seen at Hatfield Forest and they took no participation in the butterfly profile of the rides. I do not know the site well enough to understand why that is.

Hatfield Forest - Small White were seen on two occasions only, the 12th of August when one was seen, followed by a visit a few days after "White Day" at The Naze to record 4 sightings on the 18th of September, meaning the influx of migrant Small White had not come that far inland. Total: 5
River Chelmer Valley reserves & River Can, West Chelmsford

It would be fair to say that recorded sightings along the riverbanks both North along the Chelmer Valley, and West along the River Can, and the Admirals Park reserve would have been a lot greater had I visited them late Summer and into Autumn. The habitats are suitable, and there was no reason to believe that numbers would have been low. As it was, I only recorded 39 in the North Essex part of Chelmsford, although this did add to the reasonably good numbers for all sightings within Chelmsford, which came to 400 - mostly seen locally within Meadgate and the River Chelmer floodplain.

Garden on Chignal Road - Small White were seen on 8 occasions with the first sighting on the 06th of April, and the final one on the 16th of September with the best numbers during August. Total: 22
River Can, Bell's Meadow & Admirals Park LNR - Small White seen on the 07th of May, and the 21st of July. Total: 6
Great Notley Country Park
Great Notley Country Park - Small White were seen on two occasions, the 06th & 18th of September in small numbers. Total: 18
The Naze, Holland Haven Marshes, Great Holland Pits, & Walton-on-the-Naze/Frinton-on-Sea esplanade
The coastline from Holland Haven Marshes to The Naze peninsula was by far the location with the highest numbers of recorded sightings of Small White within Essex on one day. The Summer brood were definitely bolstered by the abundant migrants that arrived along the sea wall and cliffs during the first two weeks of September. It is a good place to see whites anyway with Sea Beet Beta vulgaris subsp. maritima growing prolifically along the Essex coastline around The Naze, and various mustard brassica field escapees close to the reserve.

The Naze - only two visits with 10 seen on the 02nd of May, and the 15th of September when migrants arrived with 181 seen. Total: 191
Great Holland Pits, Holland Haven Marshes & Frinton-on-Sea esplanade - one visit on the 26th of August. Total: 52
Walton-on-the-Naze, & Walton Mere - two occasions with 6 seen on the 26th of August & 19 on the 15th September. Total: 25
26th August: Great Holland Pits 6; Holland Haven Marshes 30; Frinton-on-Sea esplanade 16; Walton-on-the-Naze 6 Total: 58
15th September: The Naze 181 Walton-on-the-Naze & Walton Mere 19 Total: 200

The Butterflies of Essex
2024 Year in Review

Green-veined White Pieris napi

Summary
The Green-veined White is of least concern in the vice-counties of North & South Essex, and is a low priority for butterfly conservation within Essex. Indeed, my experience of this butterfly species suggests that it is as common as the Small White across Essex, and is more common in certain situations and climatic conditions. According to my own recorded sightings, Green-veined White came in second during 2024 for total abundance with 1378 [3 more than Small White]. This may be because I live in the floodplain of the River Chelmer which provides ideal habitat for the Green-veined White. It is hard for me to tell whether this year was any better than previous years. I suspect it was, because the warm, wet Spring meant that its larval food sources grew lush and benefited their lifecycle, like it did for the Ringlet, which I will discuss at a later date. I did not even walk down the River Chelmer to a hotspot where I have witnessed the mass emergence of a third brood during the previous two years. However, while I missed out on that experience, it was replaced during 2024 by the surprising find that they can be seen in healthy numbers along the sea wall of the Essex Saltmarsh Coast, particularly along the estuaries, which I was not expecting. Unlike Small and Large White, I am not sure that their numbers were boosted by an influx of migrants during the first two weeks of September - I expect not, which would suggest total abundance was over 200 more than that for Small White before adding migrant numbers. And, like the previous two years, this was most likely spread over three broods.

The 2024 distribution of the Green-veined White, limited this time to recorded sightings on the iRecord website, shows a widespread distribution across Essex:
And the recorded sightings for the last 10 years, according to the data collected on iRecord which includes the transects, shows an almost total distribution across the whole of Essex. It is notable that the density of recorded sightings is higher along rivers and within wooded areas which is what I have found from my own experience. We have to accept that there is more butterfly recording being carried out in East London and close to other higher population density areas. Despite that, I think the distribution maps on iRecord do begin to show the type of habitat that the Green-veined White prefers and where they can be found in Essex:
As I already mentioned, my local butterfly sites lie within the floodplain of the River Chelmer and north along the Chelmer Valley, as well as west along the River Can through Admirals Park. What these places have in common is damp, lush, tall forb habitat including Garlic Mustard Alliaria petiolata, Cow Parsley Anthriscus sylvestris, and Nettles Urtica dioica which grows generally in dappled shade providing a sheltered, warm microclimate that benefits Green-veined White among other woodland edge/hedgerow/scrubland favouring species. My own distribution map on iRecord reflects the fact that I walked the local riverbanks during Spring, the rides within wet woodland during July, and, as mentioned earlier, the river estuaries and sea walls of the Essex Saltmarsh Coast during August to October. I pretty much saw them in good numbers wherever I was:
And the abundance during 2024 according to my recorded sightings at these site locations confirms this:
Interestingly, 5 of the first 11 site locations with the highest total abundance [<40] are found along the river valleys and floodplains of the rivers flowing through Chelmsford - the other 6 being in woodland and coastal locations.

The abundance over time during 2024 according to my recorded sightings for the date of the site visit reveals three peaks which may indicate two peaks for the Summer Brood, or an early emergence and peak of the Summer Brood, with a third brood boosting numbers in late August into September:
Unlike the other two common whites, numbers were good during three seasons although there was an increase towards the end of the Summer. There was not a massive upturn in numbers during the first two weeks of September and they did not take a significant part on "White Day" at The Naze or later along the Essex Coast during the time when an influx of whites flew in from the continent. The first sighting was on the 2nd of April in Meadgate Fields Open Space, with steady numbers peaking on the 07th of May for the Spring Brood along the River Can and within Baddow Meads. The Summer Brood began during the last week or so of June with numbers peaking on the 14th of July at Lingwood Common and Baddow Meads. Numbers remained healthy for the rest of the Summer with additional emergence towards the end of August into September, peaking on the 26th at Great Holland Pits and Holland Haven Country Park, with similar numbers the following day on the 27th of August along the sea wall at Burnham-on-Crouch, with the highest single totals for any particular day. There were still good numbers into mid-to-late September with the final sighting on the 04th of October, 6 months after the first sighting of 2024. As I mentioned earlier, I did not walk the River Chelmer in September to search for third brood Green-veined White but numbers did tend to replicate the three broods of previous years.

Highlights
Good numbers would indicate that the Green-veined White is doing okay in Essex, and that is particularly true locally where numbers once again were excellent. The fact that I saw 80+ along the sea wall at Burnham-on-Crouch on the 27th of August was a real surprise to me. I have not quite worked out why I should be surprised or what the lifecycle is for the Green-veined White along the sea wall of a river estuary in Essex. That is something I want to look into during 2025. It would help if I knew what larval food source they are using. I suspect they are using the same as the Small White - Sea Beet Beta vulgaris subsp. maritima , perhaps a combination of Sea Beet and Hedge Mustard Sisymbrium officinale and agricultural cultivar field escapees, although I did not see a lot of either. In terms of sightings, I think I saw more Green-veined White in cop than any other species during 2024 - a lot of nuptial gift giving going on, I suspect.

David Lazarus wrote: ↑Mon Jan 20, 2025 6:24 pm...Good numbers would indicate that the Green-veined White is doing okay and that is particularly true locally where numbers once again were excellent...

Those numbers you report are impressive, David. This species seems to be becoming scarcer round my way with every passing year.

I can't recall the last time I saw more than a dozen at a single site.

David M wrote: ↑Mon Jan 20, 2025 9:42 pm ...this species seems to be becoming scarcer round my way with every passing year.

I can't recall the last time I saw more than a dozen at a single site.

That is a real shame, David, as it is a beautiful butterfly with lovely habits and behavioural quirks. When I wander around the floodplain and riverbanks and see lots of Green-veined White, with the Orange-tip sharing the same habitats, it really starts to feel like Spring has arrived - not long now. I wonder why numbers are diminishing near you - I tried to have a look at the records this morning for your area but unfortunately both iRecord and Butterflies for the New Millennium Online websites are down. Hopefully, they will be back online shortly so I can get back to my 2024 Year in Review.

David M wrote: ↑Mon Jan 20, 2025 9:42 pm This species seems to be becoming scarcer round my way with every passing year.

The iRecord website is up and running again, and I have just taken a quick look, David. I can see the distribution of recorded sightings in Wales has drastically reduced during the last 10 years. However, this could also be because less people are recording their sightings and/or not going to certain places to record sightings. Unfortunately, I can’t look at the abundance figures to see how much this has affected total recorded sightings as I haven’t got access to download them.
What interests me more is how the distribution maps show that Green-veined White recorded sightings are generally along the river valleys of Wales [mostly, I would say], and lowland woodland areas under a certain elevation above sea level - I can’t tell what that is from the iRecord maps.
I wonder what the reason for reduced occurrence is - certainly not climate, so reduction in larval food source because of what reason? Development, change in Forestry practices, agricultural practices, pollution/pesticides, some sort of disturbance to the ideal habitat conditions - humans don’t like large patches of Garlic Mustard, Cow Parsley, & Nettles [and other tall flowering herbaceous plants (weeds)] recreationally or otherwise unfortunately.
As you are well aware David, habitat reduction/loss & connectivity issues is probably the biggest factor for the local extinction of butterfly species - and I am not sure if Green-veined White is even considered a habitat specialist, which of course it is.

Edit - update AI generated answer: “The Green-veined White butterfly (Pieris napi) is not a habitat specialist, but it can be found in damp grassland and woodland habitat”.

One of the problems we have in the fight for the conservation of our butterflies.

The Butterflies of Essex 2024 Year in Review continued

South Essex

The following locations are where sightings of Green-veined White were recorded by me during 2024 within South Essex:
Baddow Meads & Meadgate Fields Open Space
The floodplain south of the River Chelmer contains large patches of Garlic Mustard Alliaria petiolata within its damp open grasslands and woodland habitats, as well as along the riverbanks of the Chelmer. Most of the early sightings are within the damp, warm, and sheltered openings within the wooded areas. Later on in the year the riverbanks come into their own with lots of males flying up and down the riverbanks, with females fluttering low in the nettle patches and damp grassland areas which now mimic the dappled shaded areas of the woodland in Spring. Although Green-veined White do not lay their eggs on Cow Parsley Anthriscus sylvestris or Nettles Urtica dioica, these two plants seem to play an integral role in the lifecycle of the Green-veined White locally by creating a favourable microclimate, providing a location for mating, roosting and perching, and maybe, in the case of Cow Parsley, a nectar source although I am not sure I have witnessed this. I am still in the process of observing the behaviour of butterflies within these habitats. I have thought that, surely, Cow Parsley plays an important role in the lifecycle of both Green-veined White and Orange-tip during Spring but I am yet to find what this is other than they are both there, especially early in the day, and I will go searching there to find them. I will discuss the camouflage of Orange-tip later. Perhaps it is the same with Green-veined White - the underwings blend nicely with Cow Parsley and function as a place to avoid predation as well as, maybe, keeping the wings dry and warm - not sure though.

What is clear, the plant community containing large patches of tall-forb within the dappled shade of woodland edge, rides, and glades within damp locations, which includes riverbanks, provide the ideal conditions for the lifecycle of the Green-veined White and I would suggest that this is the prime habitat for this particular species. Unfortunately, aesthetically it is not pleasing for humans and is at risk of destruction. The main problem locally is the loss of this habitat by the invasion of exotic and invasive species that outcompete these native species. The main culprit is Himalayan Balsam Impatiens glandulifera which needs to be controlled. It has already got to the point locally that it will now take a massive and sustained effort to rid the riverbanks of this aggressive self-seeder. If conservation work does not involve the sustained manual removal of this plant over several years - not spraying with herbicide, which will be detrimental to the ideal plant community we want to conserve - local extinction of the Green-veined White in one of the hotspots of this species will sadly be the result.

Baddow Meads - The first sighting of the Spring Brood was on the 08th of April, peaking at the end of April, with numbers declining by the last week of May. The Summer Brood was emerging in good numbers by the end of June with significant numbers by mid-July maybe peaking around the 20th of July with 25 seen on that day, with sightings continuing into the second week of September with a possible third emergence peaking around the 08th of September [as I mentioned previously I did not focus my attention, unlike the past couple of years, to compare numbers]. Total: 174
Meadgate Fields Open Space - The first sighting of the year occurred on the 02nd of April with numbers peaking on the 29th of April with 16 and tailing off until the 22nd of May. The first Summer Brood sighting was on the 01st of July with numbers peaking around the 16th of July. The last sighting was on the 09th of August and probably indicates that a third brood did not occur in these damp wooded areas on the fringe of the floodplain. Total: 97
Meadgate Park - Recorded sightings occurred from the 05th of April in small numbers [as it is not a home to a colony and lacks larval food sources] with numbers continuing until the 20th of May. A few Summer brood were seen from the 03rd of July, with the final sighting on the 23rd of July. Total: 24
Garden on Meadgate Avenue - a few wanderers only. Total: 5 with a couple at Baddow Hall Park. Total: 2

Lingwood Common, Danbury Ridge Nature Reserves, & Danbury Common
Lingwood Common is a mosaic of habitats with most of the site a wet woodland, very damp in the Spring. It has sufficient Garlic Mustard Alliaria petiolata, with nectar-rich tall forbs along the woodland edges, and short grass flowering plants such as Bugle Ajuga reptans and various daisy type flowers within the open grasslands and wet heathland, to support a reasonably healthy-sized colony of Green-veined White. Numbers were good, and this was particularly so along the southern edge when they were nectaring along the ditch on thistles and clover within the field margins.
The other nature reserves do not contain large numbers which is a shame - the woodlands are dark and probably various species would benefit from a 5-year cycle of coppicing and the restoration of a herbaceous layer. Little Baddow Heath has visitors on the forb-rich grassland area.

Lingwood Common - Green-veined White were seen on 8 occasions [which tended to be 3-4 weeks apart] with the first sighting on the 13th of April. More Summer Brood were seen when I was searching for Purple Emperor, with the first sighting on the 08th of July peaking on the 26th of July with 27 seen. There were recorded sightings on a couple of visits in August and September with the final sighting on the 11th of September. Total: 89
Scrubs Wood - a few sightings from the 20th of May to the 19th of August with half-a-dozen seen on the 05th of August. Total: 9
Danbury Common - sadly, another species that is not in great numbers at this location. Total: 5
Poors Piece & Heather Hills nature reserves - also, poor numbers. Total: 6
Maldon Wick
This is an Essex Wildlife Trust nature reserve with an open grassland area containing a forb-rich meadow created as an offset for development with the northern end of the reserve cut off by a new road and sold off to developers. The wooded area borders the meadow with the remains of a wet, mixed deciduous woodland running along a disused railway embankment. There is also a nearby wet woodland - Hazeleigh Hall Wood which suppots various butterfly species including White Admiral. The embankment is surrounded by new development, and the wood by agricultural land. Despite this the woodland has an interesting mix of plant communities forming the herbaceous layer and good quantities of Garlic Mustard Alliaria petiolata which supports the Green-veined White colony.

Maldon Wick Nature Reserve - Only two visits with good numbers of Spring Brood in May, and one of the few locations that I recorded a sighting of a Green-veined White on my visit in June. Total: 18

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Woodham Fen, Fen Creek, Marsh Farm, & the River Crouch
Damp open grasslands on both sides of the River Crouch estuary with areas of scrubland provide some habitat for low numbers of Green-veined White.
Fen Creek - one visit on the 13th September. Total: 9
Woodham Fen Nature Reserve - one visit on the 13th September. Total: 7
River Crouch, Marsh Farm Country Park, & South Fambridge - 13th of September, with 2 extra treks around the estuary on the 03rd & 04th of October produced some of the latest sightings of 2024. Total: 10
Wallasea Island, & the Burnham-on- Crouch sea wall, including Holliwell Point
Another location along the River Crouch estuary which includes damp, open grassland with reeds and tall forbs, including late summer flowering daisy-type plants. Minimal scrub along the dykes, with areas of bramble are also present. How this supports Green-veined White and what larval food source they use needs further research.

Wallasea Island - Green-veined White were seen on 3 late season occasions between the 29th of August and the 14th of September with 42 seen on the 07th of September which maybe indicates a third brood or an extended late Summer Brood emergence.
Perhaps one of the most surprising finds of a great deal of searching for butterflies during 2024 - generally not for relatively common species such as the Green-veined White. As I mentioned previously, I do not know why I should be surprised as this is still a riverbank despite being subject to coastal climatic conditions and lacking woodland areas. These habitats and how or why they support butterfly species such as Green-veined White and the Wall need further investigation and a recognition of what habitat-factors benefit each stage of their life cycle. Very fascinating and something I will be dedicating time during the next 10 years to research by observation. If anyone reading this has more information and experience to comment it will be much appreciated - thank you in advance .

Burnham-on-Crouch, England Coast Path to Holliwell Point - Remarkable numbers on just one visit on the 27th of August. Total: 82

Hockley Woods, Pound Wood, & Hadleigh Great Wood
Green-veined White take advantage of the damp conditions within the woods along the rides and glades. Reasonable numbers occur there but I would expect to record more sightings if I visited there more regularly. They can also be seen along the woodland edges and hedgerows bordering the fields adjacent to the woods.

Hockley Woods - Green-veined White were seen on 3 occasions from the 24th of May until the 15th of August in small numbers. Total: 9
Although damp conditions exist within both these woods, numbers of recorded sightings at these locations are small.

Pound Wood - single sightings on 2 visits on the 04th of July and the 15th of August. Total: 2
Hadleigh Great Wood - Green-veined White only seen on one visit on the 04th of July. Total: 7

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Benfleet Downs, Canvey Island, & Two Tree Island
Benfleet Downs is not a site I would associate with large numbers of Green-veined White. Being on a South-facing slope, the soil is well-drained and the required dampness with large patches of Garlic Mustard Alliaria petiolata are not present. However, I am not familiar with the site and have not walked around the whole of the landscape.

Benfleet Downs - A few Green-veined White were seen on the two late summer visits on the 28th of August and 17th of September. Total: 6
The Canvey Island Loop is located within a river estuary with a sea wall that has sloping open grasslands with scrub including brambles. A surprising number of Green-veined White, once again I am not sure why. Canvey Wick Nature Reserve is south-west of the island adjacent to marshland. It is a post-industrial site that appears overgrown with scrub dominant amidst damp woodland habitat criss-crossed with a number of paved rides. Unfortunately, I only visited the reserve once late in the day and there were few sightings.

Canvey Island Loop - One visit on the 30th of August. Total: 59, plus Canvey Wick Nature Reserve. Total: 2
A mixed habitat of open grassland and scrubland, there were reasonable numbers on the one visit despite poor weather.

Two Tree Island - one visit on the 28th of August. Total: 29
Hadleigh, England Coast Path - one visit along the river estuary coastal path between Leigh-on-Sea and Benfleet on the 28th of August. Total: 11
One Tree Hill, Northlands Wood, & Willow Park
I would expect the mosaic of woodlands and open grassland habitats to support larger colonies of Green-veined White than my recorded sightings would suggest. This is partially because of the times I visited and the habitat that I searched was not favourable to high numbers. They fly up and down the ride at the top of Johnson's Meadow- West.

Langdon Hills Country Park, including One Tree Hill - Johnson's Meadows. Green-veined white were seen on 5 occasions between the 01st of May and the 13th of September with the highest numbers during the Spring visits. Total: 41
Northlands Wood & Great Sutton Wood - one visit on the 13th of August. Total: 12
Willow Park - two visits on the 19th of May and the 13th of September. Total: 5
Thames Estuary Path and EWT Thameside Nature Discovery Park
Although not in great numbers, Green-veined White frequented both the wooded areas around Thameside Nature Discovery Park and along the sloping open grasslands of the sea wall. I would expect greater numbers if I had visited frequently throughout the year instead of the few visits during late summer.

Thames Estuary Path - Green-veined White were seen on two visits on the 19th & 20th of September. Total: 13
EWT Thameside Nature Discovery Park - one visit on the 19th of September. Total: 15

Rainham Marshes
Green-veined White can be seen mostly around the car park verges and the scrub and wooded areas just inside the reserve.

Rainham Marshes - Green-veined White were seen on 3 occasions between the 17th of July and the 28th of September with most seen on the 17th of August [22]. Total: 30
Claybury Park
Claybury Park has a mosaic of mixed deciduous woodland, scrubland - including plenty of Blackthorn Prunus spinosa and Brambles Rubus fruticosus - and is one of the two sites in Essex, alongside Rainham Marshes, that has Brown Hairstreak. I would expect the habitat to support Green-veined White but I did not see many of them on my single visit during 2024.

Claybury Park - one visit on the 18th of August. Total: 2

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The Butterflies of Essex 2024 Year in Review continued

North Essex

The following locations are where sightings of Green-veined White were recorded by me during 2024 within North Essex:
Hatfield Forest
The woodland rides of Hatfield Forest are damp with habitat and microclimate that favours Green-veined White although they are not present in the numbers I would expect. They did though form a component of the butterfly profile for July and August.

Hatfield Forest - Green-veined White were seen on 3 monthly visits from the 19th of July to the 18th of September. Total: 62
River Chelmer & the Chelmer Valley LNR, and the River Can & Admirals Park NR
Admirals Park is one of the main areas that Green-veined White are common with large patches of Garlic Mustard Alliaria petiolata, Cow Parsley Anthriscus sylvestris, and Nettles Urtica dioica all along the riverbanks with trees providing dappled shade and the landscape often flooded during periods of heavy rain. Likewise the River Chelmer to the north of Chelmsford runs through local nature reserves which are wet woodlands and consist of riverine habitat conducive to good numbers of Green-veined White. All along the northern banks of the River Chelmer, as it flows east towards the coast at Maldon are similar areas of tall forbs and wet woodland areas as well as scrub. There is a particular site close to Sandford Lock which is particularly damp with a mature herbaceous layer under a plantation of willows Salix spp. where third brood Green-veined White emerge in good numbers.

River Can & Admirals Park Local Nature Reserve - Green-veined White were seen on 8 occasions, with the first sighting on the 24th of April with the Spring Brood peaking around the first week of May with 41 seen on the 07th of May. The last sightings were on the 21st of July but I did not walk the riverbanks after that date. Total: 92
Garden on Chignal Road - a few visitors on 6 occasions between the 30th of April and the 06th of August. Total: 14
Chelmer Valley Local Nature Reserve - Green-veined White were seen on a couple of visits during May, the 09th and 12th and would expect 100 plus if visited more regularly. Total: 54
Also, further north at Newland Grove NR Total: 21 & Little Waltham Meadows NR Total: 13
Northern banks of the River Chelmer, Barnes Mill Lock to Sandford Lock - a very common butterfly along the riverbanks, I only visited on a few occasions and did not walk the banks at the times I would usually see abundant Green-veined White when 100 plus would be expected minimum. Total: 52
Total for Chelmsford during 2024: 550
Great Notley Country Park
As with other species at this park, numbers are not great and I am yet to find out the reason why. They are looking to make improvements to the way they manage the habitats. It could not get any worse as it is.

Great Notley Country Park - Green-veined White were seen on a couple of visits on the 08th of August and the 06th of September. Total: 11

Friday Wood & Cherry Tree Lane
Friday Wood and the surrounding landscape provides an ideal habitat for Green-veined White with its wet, mixed deciduous woodland with the River Roman flowing through it, and marsh and wet open grassland surrounding it. Even so, numbers were low on the few visits I made. I would expect higher numbers along with Ringlet and Large Skipper.

Friday Wood - Green-veined White were seen on 2 visits during July, the 11th and 18th. Total: 25
Great Holland Pits
A good location to see large numbers of Green-veined White with wide forb-rich grassland rides and damp sheltered microclimates within the woodland edges, rides and glades. The highest numbers at one site in North Essex were seen at Great Holland Pits - this is a 150-200+ location for seeing Green-veined White on a regular basis.

Great Holland Pits - Green-veined White were seen on 4 occasions with the first sighting on the 12th of April, with the most seen on the 05th of May [28], and the final sighting was on the 26th of August. Total: 93
Holland Haven Marshes & Country Park
A location that I do not visit regularly but it does have a suitable mosaic of habitats to support Green-veined White with marshland bordering onto scrubland and wet open grassland areas.

Holland Haven Country Park - Green-veined White were seen during one visit on the 26th of August. Total: 22
Frinton-on-Sea esplanade, Walton-on-the-Naze, & The Naze
Green-veined White were in reasonable numbers along the sea wall from Frinton-on-Sea to The Naze despite the lack of preferred habitat. I did see females ovipositing on what seemed to be Sea Beet Beta vulgaris subsp. maritima.

Frinton-on-Sea esplanade - one visit on the 26th of August. Total: 16
The Naze - Green-veined White were seen on 3 occasions from the 12th of April to the 15th of September. Whilst there were 200+ of both Large & Small White on the 15th of September I only came across 2 Green-veined White. Total: 17