All the news from RSPB Lakenheath Fen - 2 June 2021

Hello and welcome to this weeks' blog. Things really warmed up at the weekend and this hot, sunny weather has really boosted butterfly and dragonfly numbers on the reserve. A walk at the moment in weather like this should reward you with hairy dragonfly, four-spotted chaser, azure damselfly, red-eyed damselfly (especially from the dragonfly platform) and common blue damselfly. We have also had reports of banded demoiselle, scarce chaser and brown hawker now too. Today brought our first sighting of black-tailed skimmer now too- see the lovely photo below. We seem to have had a bit of an influx of red admirals from the continent, and we had a report of a clouded yellow from Joist Fen on 30 May. Its often the case that once some migrant species begin to appear, others will soon follow- so we will be keeping our eyes out for painted lady butterflies and silver Y moths in the moth trap this week. Holly blue, small heath and orange tip are plentiful, and small copper are becoming more regularly seen. The Brandon Fen family trail and the riverbank footpath are good places to look for butterflies, whereas dragonflies can be seen almost anywhere perched on vegetation.

 Photo credit: Black-tailed skimmer (female) by David White, taken on 2 June 2021.

You will also notice a wider range of flowering plants on the reserve, and water violet is a scarce speciality of Lakenheath Fen- it's beautiful lilac-and-yellow blooms decorate the water's edge opposite Trial Wood Viewpoint- along the section of hard track that runs parallel to the southern edge of New Fen. There are four cleared areas of reed along this edge, two of which have water violet blooming within easy view. Water violet is on Britain's Red Data List because it has undergone such serious declines in recent decades, partly because it is so vulnerable to water pollution- until it flowers, water violet is completely submerged so poor quality water affects it even more so than for a plant which grows partly above the water line. H

There's a tiny little bit of brooklime beginning to flower by the log at the Photography Station, hopefully before long it will have spread into a sizeable patch. This is another damp-loving plant. Along the edges of the entrance track is a sea of cow parsley and common comfrey- the two plants look beautiful together and attract a huge range of insects. If you don't mind being passed by the odd car arriving or leaving, this is an excellent spot for a bug hunt and the large and beautiful violet ground beetles and similar bronze ground beetles can often be seen scurrying across the track from one side to the other. Look out for holly blue butterflies in the trees and shrubs too.

In terms of bird life, it is difficult to know where to start... the bitterns perhaps? Whilst booming is becoming less frequent across the reserve, it is getting more likely to see bitterns in flight over the reedbeds or even chasing each other, as seen in the photo below from 31 May. These are likely to be territorial disputes between one or another of our 11 booming males and interfering males trying to muscle in on their patch.

 
 Photo credit: Both taken by Junita Davies on 31 May 2021. The bird in front was very vocal during the chase!


Our hobbies have continued to delight with up to twenty still using the reserve to hunt dragonflies. We are likely to lose a few more as they move away to their summer breeding sites but we will keep a few pairs so they will be visible all summer.

Our last migrant bird to arrive came in the form of a pair of spotted flycatchers, who have taken up residence in East Wood, using the clearings to hunt for insects from high perches in the poplars. Many of you will have heard of the sporadic reports we have had of golden orioles in West Wood- and to clarify, we are still waiting on a confirmed report. As far as we know, no-one has an image, video or sound recording of an oriole taken on the reserve this Spring, and none of our volunteers nor staff have seen or heard any. It is possible that we have had single birds passing through very quickly, as we have had four or five separate reports, but we just can't verify them. We do have a very melodic blackcap singing in West Wood which might make things confusing at times, and female orioles do have a resemblance to green woodpeckers which has caused confusion in the past for us here. It is now getting a bit late for further records. If we do get any confirmed sightings, we will update our blog and social media pages straightaway.

As you walk around the reserve, keep an eye out for marsh harriers flying low over the reedbeds and passing prey to each other- seeing a male giving caught food to a female in mid-air is a frequent sight at the moment. The harrier chicks will be growing fast and males are kept on their toes (or wingtips?!) trying to catch as much food as possible. You should also hear several reed warblers, Cetti's warblers and reed buntings. Sedge warblers are here in very good numbers as usual, but very quiet at the moment, likely because they are busy raising their first broods of chicks. Each summer both reed and sedge warblers will attempt multiple broods- sometimes three or even four- and so the singing of the males of each species follow cycles of quiet periods followed by singing as males try to reinforce their territories and perhaps attract another female if the initial pairing didn't work out. As sedge warblers tend to arrive about a week to ten days earlier than reed warblers in Spring, these cycles are offset so often when the sedge warblers first go quiet, the reed warblers are quite vocal, and then the reverse, all summer long. Our grasshopper warblers have now gone quiet and it seems as if the single Savi's warbler singing part way to Botany Bay has also settled down to breed- he wasn't singing for long before he went incognito! As with the other warbler species though, we can expect the grasshoppers and our Savi's to sing again briefly between broods, so do listen out for them when you visit. Here's a recording sent in to us by a visitor if you'd like to listen. Savi's warblers have a higher, faster 'whirr' than a grasshopper warbler which often sounds like it's coming from a man-made generator, to my ears anyway!

Video credit: Dan March, recorded on 23 May 2021.

Back at the Visitor Centre, our moth trap catch is increasing in number and variety and we thought we'd take full advantage of this warm weather last weekend- on the evening of 29 May we caught:

In terms of reserve news, the work parties have now finished their wonderful painting and cleaning jobs for the summer ahead- all of our benches have had a spruce up and a lick of paint, and this week they are working on fencing repairs on Cowles Drove and strimming jobs around viewpoints and the dipping pond to try and get it ready for service. I also hope tomorrow to give the Breckland plant raised bed a bit of a rejuvenation... watch this space! By the weekend it should be looking much better than it does now. It also gives me an excuse to sit in the sun for a bit!

With best wishes for a happy week ahead,

Heidi Jones
Visitor Experience Officer, RSPB Lakenheath Fen

p.s. Here’s a quick reminder of the facilities we have on offer for visitors at the moment:

Car park and trails open daily, from dawn until dusk. We have a small path closure south of Trial Wood, but this does not affect a visitors’ ability to do the long circular trail to Joist Fen through the reserve and back via the riverbank).

Toilets (including an accessible one) available from 09:00 to 17:00 in the week, 09:00 to 16:30 at the weekend and bank holidays.

Outdoor, COVID-secure ‘Meet & Greet’ at the Visitor Centre from 09:00 to 17:00 in the week, 09:00 to 16:30 at the weekend and bank holidays.

Takeaway refreshments, pin badges, greetings cards and local wildlife prints available to browse and buy from our Visitor Centre available 09:00 to 17:00 in the week, 09:00 to 16:30 at the weekend and bank holidays.

Binocular hire and disabled parking facility (at New Fen) subject to availability on the day but on offer from 09:00 to 17:00 in the week, 09:00 to 16:30 at the weekend and bank holidays.