Re: David Lazarus
Posted: Sun Jun 30, 2024 1:22 pm
A species focus on the Heath Fritillary in Essex: status - highly threatened
28/06/2024 Site visit: South Essex woods
In The Heath Fritillary in Essex - 2015 report, produced by the Essex Wildlife Trust Biological Resource Centre, the collected data for adult trends showed that the populations in the four Essex woods in which the Heath Fritillary was introduced were still in decline and that the butterfly was severely threatened with extinction.
The report contains the following conclusions for each of the woods:
1. Hockley Woods
Population Trend: stable, following severe decline
Population Status: at risk
2a. Hadleigh Great Wood
Population Trend: severe decline
Population Status: severely threatened
2b. Dodds Grove
Population Trend: stable at low levels
Population Status: severely threatened
3. Pound Wood EWT
Population Trend: severe decline
Population Status: severely threatened
4. Thrift Wood EWT (SSSI)
Population Trend: severe decline
Population Status: extinct (2014 to present)
There are no plans for EWT to reintroduce the Heath Fritillary at this site despite the wood sustaining a population for 30 years up to 2013.
This leaves the three sites Hockley Woods, Hadleigh Great Wood & Dodds Grove, and Pound Wood with the Heath Fritillary continuing to be a highly threatened species vulnerable to extinction at all three woods in Essex. These are the three sites that I have collected data and observed the health of the Heath Fritillary and the patches of Common Cow-wheat Melampyrum pratense, an annual plant, on which it depends.
Nearly ten years later, the Essex Wildlife Trust this week released a news article entitled Highest number of heath fritillaries recorded where they state that the record numbers of 148 heath fritillary butterflies were announced in 2019, and that record was beaten in 2024 during which 218 were recorded at Pound Wood nature reserve in south Essex, making it the highest number the Trust has seen to date. [source: https://www.essexwt.org.uk/news/highest ... s-recorded].
I have visited 4 times during the last month with my penultimate visit taking place on Friday 28th June last week. Although the weather conditions were not ideal for this warmth and sun-loving butterfly, it was sufficiently good enough during the brief sunny intervals to collect data on adult numbers. My final visit next week will be subject to the weather with the forecast not great.
Hadleigh Great Wood has one tatty female left signalling the end of the flight period for 2024 at this site for another year especially given the cool, wet weather forecast for the next four days. I personally have not seen more than 4 at this site in only one colony of the two places left with sufficient cow-wheat to sustain a population. Others have found 12 or so. No one has found Heath Fritillary at Dodd's Grove and the glade is not currently in a state to attract further colonization.
The news is far better at Pound Wood and Hockley Woods where the main colonies now reside. I counted 55 Heath Fritillary at Pound Wood on Friday down from a peak of approximately 100. At Hockley Woods I counted 59 which is down from a peak of between 200-250 individuals. Over the 3 woods, I would say the peak count for 2024 was around 350. I would question the count of 500 at Hockley Wood on one day as a significant exaggeration. I actually think the EWT's count of 218 was probably an over-estimation being double the amount I saw on two occasions during the peak flight period.
It will probably be no surprise to you that at both sites there were fewer males seen than on previous visits. There were some freshish-looking females at Pound Wood:
and this included some being pestered by males and some laying eggs:
But you are more likely to see this now at Pound Wood:
than a few of these:
But there is always the occasional beauty to behold:
It is much the same at Hockley Woods in the main four colonies within the South Essex Woods, with significant reductions in abundance and what is there containing a higher percentage of females that have been around for a week or so:
with a few newly emerged ones:
the odd dead one:
but the majority are not looking at their best:
having said that, there is still a bit of activity going on:
It has been a joy and delight to be amongst this beautiful, delicate, and vulnerable species for the past month. The Heath Fritillary is one of my favourite butterflies and I cannot wait to do the whole thing again in 2025 and beyond.
One sadness was the amount of flattened vegetation. Unfortunately, I suspect most of this was the result of butterfly enthusiasts attempting to acquire the perfect shot while ignoring the fact that there was plenty of larva and pupa under their feet. Some of the areas in both Hockley Woods and Pound Wood had grass patches that had been trampled on resulting in significant loss of perching, basking, & roosting sites as well as places that the Heath Fritillary enjoy meeting the opposite sex. The Heath Fritillary also lays it's eggs low within the grass and plant litter close to the cow-wheat. Please, if you are going to the woods, keep to the paths or the visible trails through the cow-wheat, and don't venture off them into the vegetation even if it is grass or over plant litter - certainly please do not trample on the cow-wheat. And please watch your feet as they are low flying and regularly rest on the floor within vegetation and leaf litter.
Enjoy, and celebrate the fact that 2024 had a healthy emergence of Heath Fritillary in Essex.

28/06/2024 Site visit: South Essex woods
In The Heath Fritillary in Essex - 2015 report, produced by the Essex Wildlife Trust Biological Resource Centre, the collected data for adult trends showed that the populations in the four Essex woods in which the Heath Fritillary was introduced were still in decline and that the butterfly was severely threatened with extinction.
The report contains the following conclusions for each of the woods:
1. Hockley Woods
Population Trend: stable, following severe decline
Population Status: at risk
2a. Hadleigh Great Wood
Population Trend: severe decline
Population Status: severely threatened
2b. Dodds Grove
Population Trend: stable at low levels
Population Status: severely threatened
3. Pound Wood EWT
Population Trend: severe decline
Population Status: severely threatened
4. Thrift Wood EWT (SSSI)
Population Trend: severe decline
Population Status: extinct (2014 to present)
There are no plans for EWT to reintroduce the Heath Fritillary at this site despite the wood sustaining a population for 30 years up to 2013.
This leaves the three sites Hockley Woods, Hadleigh Great Wood & Dodds Grove, and Pound Wood with the Heath Fritillary continuing to be a highly threatened species vulnerable to extinction at all three woods in Essex. These are the three sites that I have collected data and observed the health of the Heath Fritillary and the patches of Common Cow-wheat Melampyrum pratense, an annual plant, on which it depends.
Nearly ten years later, the Essex Wildlife Trust this week released a news article entitled Highest number of heath fritillaries recorded where they state that the record numbers of 148 heath fritillary butterflies were announced in 2019, and that record was beaten in 2024 during which 218 were recorded at Pound Wood nature reserve in south Essex, making it the highest number the Trust has seen to date. [source: https://www.essexwt.org.uk/news/highest ... s-recorded].
I have visited 4 times during the last month with my penultimate visit taking place on Friday 28th June last week. Although the weather conditions were not ideal for this warmth and sun-loving butterfly, it was sufficiently good enough during the brief sunny intervals to collect data on adult numbers. My final visit next week will be subject to the weather with the forecast not great.
Hadleigh Great Wood has one tatty female left signalling the end of the flight period for 2024 at this site for another year especially given the cool, wet weather forecast for the next four days. I personally have not seen more than 4 at this site in only one colony of the two places left with sufficient cow-wheat to sustain a population. Others have found 12 or so. No one has found Heath Fritillary at Dodd's Grove and the glade is not currently in a state to attract further colonization.
The news is far better at Pound Wood and Hockley Woods where the main colonies now reside. I counted 55 Heath Fritillary at Pound Wood on Friday down from a peak of approximately 100. At Hockley Woods I counted 59 which is down from a peak of between 200-250 individuals. Over the 3 woods, I would say the peak count for 2024 was around 350. I would question the count of 500 at Hockley Wood on one day as a significant exaggeration. I actually think the EWT's count of 218 was probably an over-estimation being double the amount I saw on two occasions during the peak flight period.
It will probably be no surprise to you that at both sites there were fewer males seen than on previous visits. There were some freshish-looking females at Pound Wood:
and this included some being pestered by males and some laying eggs:
But you are more likely to see this now at Pound Wood:
than a few of these:
But there is always the occasional beauty to behold:
It is much the same at Hockley Woods in the main four colonies within the South Essex Woods, with significant reductions in abundance and what is there containing a higher percentage of females that have been around for a week or so:
with a few newly emerged ones:
the odd dead one:
but the majority are not looking at their best:
having said that, there is still a bit of activity going on:
It has been a joy and delight to be amongst this beautiful, delicate, and vulnerable species for the past month. The Heath Fritillary is one of my favourite butterflies and I cannot wait to do the whole thing again in 2025 and beyond.
One sadness was the amount of flattened vegetation. Unfortunately, I suspect most of this was the result of butterfly enthusiasts attempting to acquire the perfect shot while ignoring the fact that there was plenty of larva and pupa under their feet. Some of the areas in both Hockley Woods and Pound Wood had grass patches that had been trampled on resulting in significant loss of perching, basking, & roosting sites as well as places that the Heath Fritillary enjoy meeting the opposite sex. The Heath Fritillary also lays it's eggs low within the grass and plant litter close to the cow-wheat. Please, if you are going to the woods, keep to the paths or the visible trails through the cow-wheat, and don't venture off them into the vegetation even if it is grass or over plant litter - certainly please do not trample on the cow-wheat. And please watch your feet as they are low flying and regularly rest on the floor within vegetation and leaf litter.
Enjoy, and celebrate the fact that 2024 had a healthy emergence of Heath Fritillary in Essex.


