The Lyons Share

I've just got back from my monthly visit to the Ken Hill Estate where I am carrying out a series of baseline surveys before they restore some 400 ha to a more natural state. Wow, what a place. On Sunday I recorded the most invertebrates in a day's work I have ever recorded. Currently at least 275 species and with all the specimens collected it will be over 300. It was the bugs that stole the show though. Above is the nationally rare and Critically Endangered Breckland Leatherbug Arenocoris waltlii. I found two of these during the timed counts on a sandy arable field covered in Common Stork's-bill. You can see the 2nd segment of the antennae expands towards the tip and it lacks the white 'v' on the pronotum of the closely related Arenocoris fallenii. Tristan Bantock was telling me that this species is expanding its range but this record is likely to be the most northern record in the country.

After the count was finished I really felt like I needed to cover this area in some more detail so went back for an hour and it really paid off!

Here is the nationally scarce Slender-horned Leatherbug Ceraleptus lividus.

And the very hairy and fairly common Denticulate Leatherbug Coriomeris denticulatus.

I found a Rhombic Leatherbug Syromastus rhombeus too! As I was photographing this, I saw in the view finder that it ran in front of another bug. Which turned out to be the species closely related to the Breckland Leatherbug mentioned above...

...here is the nationally scarce Fallen's Leatherbug Arenocoris fallenii. Both a pale/contrastingly marked one and a browner one closer to the Breckland Leatherbug above. In both individuals though you can see the second segment to the antennae is parallel sided towards the tip and there is a white 'v' of tubercles on the pronotum.

But it didn't stop there! This is what I assume is an early instar Alydus calcaratus nymph (also nationally scarce). An amazing ant mimic.

Other nationally scarce species associated with Common Stork's-bill were Megalonotus praetextus.

And Hypera dauci. It really is just like the Brecks. There was a Woodlark singing nearby too (that refused to show itself during the bird survey). Oh and another Heath Shieldbug Legnotus picipes was there which I picked up last month on a different part of the site!

And to show how sandy it is, the nationally scarce Zelotes electus was also present. This spider is usually found on sand dunes and also the Brecks (see the BAS page above). Oh and I also hit 250 spiders for the year!

Here is that amazing bank and associated fields. With extensive grazing, it's highly likely that this already rich habitat will greatly expand. The continued presence and expansion of these kind of swards in the south could therefore act as a measure of success of the restoration.

Elsewhere in the woods there was also some excitement, with Dendroxena quadrimaculata (nationally scarce b) just sitting on a bramble leaf. This silphid is unusual in that it specialises in hunting caterpillars. It's only about the fith record I have made of this species.

And the striking deadwood cranefly Ctenophora pectinicornis. This nationally scarce species was beaten from recently fallen deadwood.

And how is it that I have seen a third of the UK's beetles but not this before?! Despite seemingly spending half my life beating oak. It's clearly not common in Sussex. The Oak Leaf-roller.

Just looking through the list, it might be the most shieldbugs, squashbugs, leatherbugs and allies that I have ever recorded in one day. Here is the full list in no particular order, 19 in all.

Bishop's-mitre Shieldbug

Slender-horned Leatherbug (NS)

Heath Shieldbug (NS)

Dock Bug

Juniper Shieldbug

Birch Shieldbug

Sloe Bug

Cinnamon Bug

Breckland Leatherbug (NR)

Fallen's Leatherbug (NS)

Rhombic Leatherbug

Denticulate Leatherbug

Small Grass Shieldbug

Green Shieldbug

Rhopalus subrufus

Stictopleurus abutilon

Alydus calcaratus (NS)

Parent Bug

Gorse Shieldbug

Now for some plants. I found a few Wild Service Tree saplings in the woods.

The Vulnerable Prickly Poppy on the sandy field to the south.

And the Near Threatened Hoary Cinquefoil on the Plain.

The bird survey was wrapped up and the highlights included Turtle Doves, Cuckoos, Whimbrel, Woodlark and much more. Wow, if May was this good, I cannot wait until the June visit! The vegetation surveys will start then too rather than just casual observations of plants.

Butcherlands. The most exciting, unpredictable and consantly changing Common Bird Census I have ever done. This is the eighth year I have carried out the four visit CBC there and it's amazing how much it's changed. Eighteen years ago this was all arable on Wealden Clay and was fenced and left to be restored to something more natural with pulse grazing by cattle currently pretty much the only management. No planting occurred and there are at least 30,000 oaks out there alone. Before looking at some of the detail though I am gonna cut right to the chase and tell you about what happened yesterday morning. First though a recap from my first visit on the 3rd April 2019. I had a Hawfinch fly over (my first since the previous winter's influx) and then surprisingly a male Dartford Warbler called repeatedly from a bramble bush. Not all that unusual to pick them up in bramble scrub away from the heaths outside of the breeding season (I've seen them in Sheepcote Valley on the edge of Brighton for example). 

Yesterday morning, the warblers were in full song. Whitethroats were EVERYWHERE. I recorded 44 singing males across the site. So when I got to the exact same area and heard Dartford Warbler calling again, I was pretty shocked. "It's holding territory!". I bungled the video last time so I got a quick video of it calling and you can see it fly from the bush to the left.

I thought I really should try and hear it singing, so I headed a few bushes away and crouched down out of view. It didn't work and the bird came towards me, scolding me from just a few metres away. I grabbed another video as it did so and it started singing a tiny bit. However what happened next was incredible. A female popped up out of the same bush! "THEY'RE HOLDING TERRITORY!". Some context here, there isn't any heather at Butcherlands, there is however hectares of low bramble scrub. This part of the site is on the edge of a sea of undulating bramble. It's also south west facing with a slightly sandy soil (more Common Bent/Cat's-ear than Heather). So it's hot, dry and with a structural component close to heather/low gorse. I never thought that this would be a thing at Butcherlands but these birds are much less fussy abroad. It may well be that this structural type and temperature envelope is rarely provided outside of the heaths in the UK.

Has anyone else encountered this in the UK before?

Yesterday morning my brain was totally fried from all the warblers. After this encounter I was doubting every Whitethroat that called, after all, if one pair of Darties could nest there, why not more? I really doubt I would have picked them up with so many Whitethroats there if I hadn't found the male three weeks ago. So many questions. So exciting!

I actually recorded over 75 singing warblers yesterday! My rule for difficult species pairs is this: if you're not sure, it's the commoner one. Think I'll call that 'Lyons' Razor'. It certainly came in handy with a few Blackcaps today. A Blackcap AND a Garden Warbler taking turns to sing from the same willow nearly made me lose my mind though.

Whitethroat - 44

Chiffchaff - 11

Garden Warbler - 8

Blackckap - 8

Lesser Whitethroat - 4

Dartford Warbler - 1

That's 76 warblers in all. Plus ten Nightingales and a Cuckoo. 

How has this changed over the last eight years though? With provisional data from yesterday's visit (this will change) the warblers look like this. A highly significant increase from linear regression. Only Chiffchaff and Blackcap came out as stable (as they are probably at capacity in the hedgerows and fields edges - for now).

And then like this if you break them down to species.

It's not all winners though. Nightingales have dipped a bit (although this trend is not significant) and Skylarks have nearly disappeared completely (a significant decline), they are still holding on this year though.

But look at the overall number of territories for all species (no suggested data here for 2019) shows a significant increase.

Species-richness of birds holding territory looks like this from 2012 to 2018 and shows no trend being about as level as it could be.

Linnet and Dunnock are two of the other species that have colonised the centre of the fields and have rocketed up significantly over the period. However the star of the show is yet to arrive. Last year FOUR Turtle Dove territories were noted and this chart shows how they have fared over the period. Wow, wasn't expecting to analyse the whole data set. Got a bit carried away there with linear regression.

I think the success of a project like this is when the site can sustain all of the species that the site has the potential to carry. So losing the red-listed Skylarks to the red-listed Linnets completely doesn't seem right to me just because we don't have an easy way of controlling the scrub. It's always early successional habitats that lose out without a constant effort to keep them open, that's why the associated species are rare. But I am also a fan of not trying to have everything everywhere all of the time. Additionally, scale is a factor here and it may not be possible to have all the successional states in 80 ha in a functional way. It shouldn't stop us trying though. How far back do you go though? After all, soon after the project started some 18 years ago (way before monitoring began) there were breeding Lapwing out there. The site would have to look very different to support them again, not something I would propose at all. You can go round and round with this. One thing is certain though, succession goes in one direction and never stops.

Over the last eight years I have recorded 73 species in the survey but this morning added another one to the list in the form of a pair of Egyptian Geese flying over. Whatever next?!