FoSL Butterfly Report 2024

Butterflies at Stocker’s Lake 2024

Cliff Buckton Oct 15 2024

The recording scheme

Weekly counts of butterflies seen in 12 sectors around the lake continued in 2024 with

results entered into the UK Butterfly Monitoring Scheme. This year’s team consisted of

Carole Holton, Simon Jones, Barbara James, Brian & Lynne Pike and Cliff & Jacky

Buckton.

Total butterflies counted by year

As widely reported in the media, 2024 has been a disastrous year for insect numbers and

butterflies are no exception. While weather during the year as a whole has been

unexceptional, rainfall in Spring was very high resulting in flooded paths around the lake for

several months. September rainfall was also well above average. This and other factors

have presumably contributed to the total butterflies counted of just 401 being the lowest

since the equally disastrous 2012. Note that 2020 was an incomplete survey year due to

Covid. For further information please view or download our full FoSL Butterflies report 2024.

Affinity Water tree works along the Mill End Loop

Affinity Water will be carrying out tree works along the Mill End Loop where the river runs parallel with Springwell Lake. The works will commence on Monday 19th August and will continue for the next 4 to 6 weeks. For those that know this section of river, will have noticed that trees aligning both banks have in places encroached across the entire river channel. These tree works aim to reduce the amount of shade imposed on the river to encourage aquatic vegetational growth, whilst conveying flows more effectively to restore chalk stream characteristics. The works being completed are creating more resilient rivers and improving habitats for the wildlife that also love chalk streams. If you would like to discuss in more detail, please contact George Horne by mailing river.restoration@affinitywater.co.uk.

Below is a map showing the extent of the works marked with a red line.

Josh Kalms

People & Wildlife Officer

01727 858901 x237

07880 094965

hertswildlifetrust.org.uk

Riverfly monitor wanted in Rickmansworth!

Would you like to help monitor water quality? Are you interested in getting in the river to survey and learn about invertebrates? Come and help out as part of an initiative with the Riverfly Partnership called Riverfly Monitoring!

Riverfly monitoring involves conducting an in river survey once a month and identifying the invertebrates you find! By identifying what is present in the river this gives an indicator of what the water quality is like, allowing for us to build long term data sets and report when water quality incidences occur. No prior knowledge is needed as all training can be provided, so please let us know at Rivers.team@groundwork.org.uk if you are interested!

A monitor is needed at a site called The Bury Grounds (pictured to the right) which is located at The Bury Gardens opposite the aquadrome. We are also interested in setting up a new site on the River Colne in the Aquadrome by Bury Lake, so please do get in touch if this is something you would like to be involved in.

Lara Clements – River Officer for the Colne Catchment

New Full season highlights of our Little Egrets livestream 2024 season

We now have a highlights video from our Little Egrets nesting season on our YouTube channel….

https://youtu.be/YcvRpaT8cwA

New - Full season highlights of our Grey Heron livestream 2024 season

We have just created and published on FoSL’s YouTube channel a full season highlights video from our Grey Heron livestream. It is an updated version of the video first shown at our AGM in April but updated to include events since then up to and including the departure of our final heron chick in late May. You can find the video below and also on our FoSL YouTube channel ….

In time we plan also to create a highlights video from our nesting Little Egrets, whose season is also now over. That video will be less spectacular, mainly because the Egrets have an annoying habit of nesting deep in foliage but also because we didn’t start following any Egrets until after the Herons’ season was over, by which time event  the later nesting Egrets had already laid their eggs. However some interesting footage was nevertheless captured and so that video too will be worth watching. So watch this space!

Cattle Egret Spotted at Stocker's Lake

This rare visitor caught on camera for the very 1st time in Stocker’s Lake . To view a clip click on the link below.

Our live stream camera was focused on a Little Egret’s nest and got this rare sighting:

A Cattle Egret shows up at Stocker's Lake (youtube.com)

Little Egrets now being livestreamed!

With our third and final heron chick having now successfully fledged and left the nest - hurrah! - our livestream camera is now trained instead on a Little Egret nest. So you can now enjoy watching live pictures of three young egrets moving around their nest area and, from time to time, being fed by a parent.

Little Egrets typically nest several weeks later than herons. So the Egret chicks, whilst already reasonably full grown, are not quite yet at the fledged stage and should remain around for another few weeks. Unfortunately Egrets tend to nest in less open sites. Their nests are generally tucked away in foliage and that of course compromises our view. However in the area on which the camera is now trained a nest can be made out amongst the foliage and there are three chicks moving in and out of view as they scramble around the nearby branches. Then every now and again an adult comes in to feed them and then a flurry of white feathers is seen.

To view live pictures of the Egrets please visit either our Livestream page or our YouTube channel. Or to review recorded footage of an adult Egret visiting the nest area and providing food please follow this link.

View highlights of our 2024 live stream to date

A video featuring stunning images from our live stream of a 2024 Little Egret nest is now publicly available. You can view it below or on our YouTube channel.

The video features the whole story to date of Little Egrets feeding of chicks; the growth and development of the chicks.

The season is still ongoing. The two chicks continue to be regularly fed at the nest by their two parents. They are expected to fledge sometime soon and then stay in the vicinity of the nest for a further 10-15 days before moving on elsewhere.

For more information on our livestream, or to view it, please visit our livestream page.

Springwell Metal Recycling Ltd – have your say!

You may already be aware that a scrap metal yard, Springwell Lane Metal Recycling ltd., recently established itself adjacent to the reserve at its SW corner.  For some time we have been concerned at the likely impacts on Stocker’s Lake wildlife. The known noise pollution is bad enough, but we also have concerns that other, even more serious, forms of pollution may emanate from the site and threaten the local wildlife.

Retrospective planning permission for the operation has now been applied for and that application contains a number of significant inaccuracies.  Hillingdon Council’s deadline for commenting on the application is Friday 5th April. So we would encourage you to consider registering an objection before then.

Springwell Metal Recycling viewed from just outside the reserve

For your information, the following are some of the more serious inaccuracies which we have spotted in the application

• In answer to "Is your proposal within 20 metres of a watercourse?" they answer “no” whereas at least part of the site is well within 10 metres of the River Colne.

• In answer to “Is the site within an area at risk of flooding?" the application states “No” whereas the entire site is within a Flood Zone

• Under Biodiversity and Geological Conservation, the form asks: "Is there a reasonable likelihood of the following being affected adversely ... on land adjacent to or near the application site?" A. Protected and priority species; B. Important habitats or biodiversity features.” They answered “no” to both whereas we know that Water Voles have been detected over the last couple of years on the banks of the Colne very close to the site plus there is a reasonable likelihood of waste, spills and pollutants entering the Colne from the site.

Viewed from its front entrance

You will find all of the above on page 10 of the application. You will note other concerns with the application too. However those are some of the major ones.

Location of Springwell Metal Recycling ltd.

In FoSL’s view this vulnerable and sensitive spot in the Colne valley is the wrong location for a metal scrap facility and what is now required of the council is enforcement action, not planning permission!

If you wish to register your objection with Hillingdon Council their planning reference is 35376/APP/2024/282. Here are links to the application form and to the full documentation set respectively:

https://planning.hillingdon.gov.uk/OcellaWeb/viewDocument?file=dv_pl_files%5C35376_APP_2024_282%5CApplicationFormRedacted.pdf&module=pl

https://planning.hillingdon.gov.uk/OcellaWeb/showDocuments?reference=35376/APP/2024/282&module=pl

To register an objection be sure to quote reference 35376/APP/2024/282 and either:

·         email applicationsprocessingteam@hillingdon.gov.uk

·         write to Planning Services, London Borough of Hillingdon, Civic Centre, Uxbridge, Middlesex, UB8 1UW

·         comment online at https://planning.hillingdon.gov.uk/OcellaWeb/planningComment?reference=35376/APP/2024/282&from=planningSearch

3 eggs --> 3 chicks --> 2 chicks!

After a relatively quiet, month long, incubation period, things recently hotted up at our live streamed Grey Heron nest. On Saturday 9th March two of the three eggs hatched. The third followed two days later. All three events were captured for posterity by our live stream.

However the drama did not end there. The third chick, born two days later than the other two, inevitably suffered an ongoing size disadvantage when competing for food and it seems this eventually put paid to him.

On 17th March, as the stream started at 6am, it could be seen that the smallest chick was not under the protection of the sitting adult, as he should have been and as were the other two, but was instead exposed on the near edge of the nest. He was still clearly alive at that time. However at 6.28, shortly after the female had fed the other two chicks but not him, she moved his body across and by now he was clearly dead. Four hours later, at 10.40, the male adult arrived …. and ate him!

It is disappointing and perhaps upsetting, but actually not all that surprising, to have lost one of our three chicks at this stage. In common with other species, part of the herons’ reproduction strategy is to advantage some chicks over others.

In this way, in good years, when food is abundant, a larger number of chicks can survive whilst in other years unequal distribution of food makes it more likely that at least some will do so. So for us, the loss of one of our chicks should at least now increase the survival chances of the other two.

As for the grisly disposal of his body, well that is also perhaps not what we wanted to see but it happens in other predatory species too, e.g. owls. Nothing is wasted in nature!

In YouTube click on the blue numbers to navigate to the right part of the footage

Note that you can view recordings of any of the incidents described in this article on our FoSL YouTube channel at www.youtube.com/@fosl01. Here you will find a full set of stream recordings since early February. Only on days when lack of solar power prevented the stream starting are dates missing. And within each daily recording all key events are indexed using YouTube chapters, making them easy to find.

So to view any of the events described, and much more, in YouTube first find the video corresponding to the date you wish to view. Then open up that video’s description field and look for a table of numbers in blue with descriptions. It will look a bit like the one pictured above. Then click on any blue number to navigate to the section of video described alongside.

All being well the two surviving chicks should steadily get bigger and stronger until around the end of April, when we would expect them to fledge. We will keep you posted but of course you can always follow their progress yourself on our livestream page or on our YouTube channel.

Heron Incubation well underway

Our livestreamed pair of nesting herons have now settled into a period of incubation. All being well we expect their three eggs to hatch around the second week of March. Until then things are likely to be quieter for a while.

Three eggs is a normal size of clutch for the Grey Heron. These were laid at two day intervals which is also normal. The first egg was laid at around at 17.26 on 10th and the second at around 16.20 on 12th. Both of these events were captured on film by our livestream. (See this earlier news item about the laying of the first egg.)

The third egg was laid on February 14th - a particularly wet and gloomy day on which our solar-powered livestream unfortunately failed to start. So we missed capturing the laying of the third egg on film but it could clearly be seen in the nest from the start of the next day’s stream on 15th. Since then the parent birds have been continuously incubating their eggs.

The male and female birds are sharing the incubation . A changeover of incubation duties has generally been occurring once or twice a day. - e.g. see this footage from around 8.30am on February 16th. Here the male (who is a bulkier bird with a more extensive patch of black on his head) is handing over to the female.

To look back on other events so far please visit our YouTube channel where you will find a complete library of all streams to date. As mentioned there was no stream on February 14th. Nor, for the same reason, was there one on February 8th. Otherwise there has, at time of writing been a stream every day since February 4th. As the season progresses the days will lengthen and the sun will strengthen. So we hope and expect that the times when no stream is possible will become less frequent.

To view live pictures of the nest please visit our livestream page.

Heron egg-laying: caught live on camera

Our new Grey Heron livestream, as announced in this earlier news item - has captured the laying of a first egg. It occurred on the afternoon of Saturday February 10th.

Have a look at this clip, which starts at 17:14 on 10th. Initially there is no egg. Then from a little before 17:18 the Heron sits on the nest but not in her usual way. She kind of crouches with her wings down. Then at around 17:26:07 an egg appears.

You can keep following progress of this Grey Heron breeding attempt via our livestream on our livestream page or YouTube channel. Hopefully a couple more eggs will appear in the coming days. Then, all being well, in March we can expect to see some young birds.

Heron Nest now being streamed live

We are delighted now to be bringing you streamed live pictures from an active Grey Heron nest at Stocker’s Lake. To view the stream live please visit our Livestream page.

Alternatively go to our YouTube channel where you will also find recordings of previous days’ streams. e.g. you can view this mating behaviour from Feb 7th.

Stocker’s Lake is home to the largest colony of Grey Herons, or “Heronry” , in Herts - around 20 nests. These are all located on an island in the north of the lake. For the last five or so years we have had a camera on the island and have been bringing you recorded images of the birds’ breeding efforts. This year, having now largely overcome some significant technology issues, we are able to stream live images.

There are limitations – e.g. there is no sound. Also the key equipment is offshore and solar-powered. Because of this the stream is off overnight and does not always get going until late morning, especially on an overcast day. On February 8th, which was especially wet and gloomy, the stream did not start at all. However we expect lengthening days to help as the season progresses.

All being well we expect the current target nest to produce hatched eggs by mid-March. Nature is however unpredictable and there is every possibility of the nest eventually failing, but if so we should be able to redirect the camera to one of several other active nests nearby. Little Egrets, which nest later, will be a possibility later on.

We will keep you posted.

Smew and breeding Kingfishers the birding highlights of 2023

Our FoSL bird recorder, Steve Carter, has just published his annual bird report for 2023. Steve’s assessment of key sightings from the year covers various highlights including the presence on the lake of a rare and attractive male Smew during February and March plus a successful breeding season for our resident Kingfishers.

Steve’s full report can be downloaded from here. Annual bird and butterfly reports from earlier years as well as information on more recent bird sightings can be found on our Sightings page.

Say "No" to Broadwater Lake development

We are joining forces with local people and other local wildlife charities such as Herts and Middlesex Wildlife Trust (HMWT) to oppose an application submitted recently by Hillingdon Outdoor Activities Centre (HOAC) to develop a new Water Sports Centre on Broadwater Lake.

Broadwater Lake is one of England’s Sites of Special Scientific Interest (SSSI) and has been a hugely important refuge for wildfowl and other wildlife for the last 40 years. FoSL believes that, if the development goes ahead, it will cause irreversible damage to the vital habitats and the wildlife of not only Broadwater Lake but also the other lakes in the valley, including Stocker’s Lake. This is because the birds migrate between the lakes, particularly when there is disturbance or food shortages.

The HOAC plan will shift the starting location for existing sailing from the north of the lake to the south and will add additional water-based activities, namely kayaking, canoeing, rowing, paddle-boarding, raft-building and windsurfing. This will mean unprecedented levels of disturbance closer to the critical refuge area in the south. HOAC claims that its plan includes new refuge areas for birds but FoSL believes these are insufficient and that HOAC is underplaying how significant the disturbance will be. Recognising the value of an educational Water Sports Centre, FoSL does not oppose developments at other non-SSSI sites in the area.

Together with Middlesex and Herts Wildlife Trust, Natural England, RSPB, London Wildlife Trust and over 1000 individuals and organisations, we have objected to Hillingdon Council's planning application to build a new Watersports Facility and Activity Centre on Broadwater Lake. The deadline for comments on this planning application was 21 December 2023 but we have been advised that the Planning Officer will accept any comments received up to Friday 12th January 2024. So please register your objection by following this link.

To find out more and for up to date news please visit HMWT’s webpage dedicated to this issue. We will also add occasional updates to this website as things develop.

Monitoring the benefits of cattle grazing on Stocker’s Lake Meadows

You may know that the reason we have cattle on the reserve during the summer is to stimulate long term wildflower growth. For further information please see this short video. So to monitor the long term effectiveness of having the cattle there we now survey the meadows concerned for wildflowers

Between April and September of this year our FoSL Wildflower surveyors completed another year of surveying Meadows 2 and 3.  Unfortunately, there are currently not enough volunteers to survey Meadow 1.  The Dexter cattle usually graze on the three Meadows from April until October.

FoSL Wildflower surveyors enjoying a coffee at Café in the Park to celebrate the end of Year 2 of surveying the Meadows

2023 was Year 2 and we are slowly building up a history.  However, it will take a good few years before seeing any significant changes.  Having said that, this year there has been slightly more bare earth showing, which should allow flower seeds to spread/settle and start to grow. The information collected is forwarded to Herts & Middlesex Wildlife Trust to be logged and will provide a picture of any changes as the years progress.  In the future, for those who are interested, we expect to publish the results on the FoSL website also.

We have only a small band of dedicated volunteers which unfortunately allows us to survey only Meadows 2 and 3.  Meadow 1 has not yet been surveyed.  Having additional volunteers would allow Meadow 1 to become part of the survey and also give the team more flexibility when someone can't make it.  We meet on the last Wednesday of the month (April to September inclusive) at 10am and are usually finished by 12-12.30.

If you have some knowledge of wildflowers and are interested in becoming part of this project, please contact Linda Ascroft, Events Organiser (email Lindajascroft@gmail.com)

Butterfly Report 2023

2023 was a great year for Red Admirals

As in previous years a small team took weekly counts of butterflies in 12 sectors around the lake throughout the summer. Following on from last year’s very hot, dry summer 2023 was much less extreme with slightly above average temperature and rainfall. These milder conditions were more favourable for butterfly development and, mirroring the national picture, produced a modest increase in numbers compared to 2022 but still slightly fewer than the average measured since 2012 with the total number counted at 586 compared to an average between 2012-23 of 644.

The most-seen species this year was the Red Admiral, Gatekeeper was next, Large and Small Whites took the third and fourth spot while Holly Blue had another good summer. Species that saw a decline from last year include Ringlet, Common Blue and Speckled Wood, all of which also show long-term declines.

For further information please view or download our full FoSL Butterflies report 2023.

Autumn Colours

Every autumn prior to leaf fall, our deciduous trees lose their green colour fading to reveal rich vibrant reds, yellows and oranges. Ever wondered why?

During summer months, the dominate leaf pigment is green chlorophyll. It is the hub of photosynthesis where light energy is used to break down carbon dioxide and water to produce sugars: energy for the tree. As autumn approaches, days shorten and temperatures drop, this energy is stored overwinter as starch in the branches, trunks and roots. But at the same time, chlorophyll production ceases and this pigment is broken down revealing the autumn leaf colours - yellow carotenes including red and pink anthocyanins – that are well known to all of us.

So next time you go for an autumn walk amongst trees you can wonder at this natural process that takes place each and every year.

Russell Ball ; photo: by Brian Cain

Stocker’s Bat boxes being put to good use

On Monday September 4th a small team comprising Patty Briggs, Nicola Padzierska and Catherine Green carried out a Bat count at Stocker’s Lake by inspecting our various bat boxes sited around the lake. Very excitingly, amongst the bats found were two Nathusius Pipistrelles, a rare species. One of these was carrying a ring which revealed it had last been detected at the reserve back in 2019. The other bore no ring and so was ringed by the team on Monday.

In addition to those two Nathusius’s the team also counted 12 Soprano Pipistrelles. The Soprano is a much commoner species but it is nevertheless great to know that it is present on our reserve and making good use of our boxes.

Nathusius Pipistrelle at Stocker’s Lake - 4th September 2023

For more information on the Nathusius Pipistrelle, which is a long distance migrant from Continental Europe, please follow this link to a web page belonging to the UK’s Bat Conservation Trust.

2024 Wall Calendars - now on sale

Following the success of our FoSL 2023 wall calendar - see the carousel display below - we have recently been busy producing another for 2024. We expect it back from the printers in early October and it is now available to pre-order.

The standard of photo in this year’s calendar is, if anything, even higher than last year’s. A total of 67 great photos were received by our deadline of July 31st from altogether 17 photographers. As a result we have been able to compile another fantastic calendar featuring altogether 19 stunning photographs - one per page for each month plus others on the front and rear covers.

As last year the calendars are A3 sized, spiral bound for easy hanging and with space against each date for marking up your diary entries. They are again priced at £10 each. Following receipt of payment they may be collected from one of our several local collection points or else posted to any UK address for an additional, small P&P charge. A final option is for later, free, local delivery although please note that significant timing restrictions apply to this.

Our 2024 FoSL Wall Calendar

Last year we had sold out by the end of November and this year we expect demand to be even higher. So please don’t delay. These make great, good value, Christmas presents. So you may want to order more than one.

To order one or more calendars please click on the link below to go to our online order form. Full details of both your collection / delivery option(s) and how to make payment are included in the form.

In the event of any queries concerning your order please email giles_lury@hotmail.com.

A rotating carousel display of our 2023 FoSL Wall Calendar