The Birds, The Bees and The Butterflies

Yesterday I was very lucky to be able to spend a full day at Knepp Estate in Sussex, one of my most favourite sites to visit. We arrived early, at 6am, for some bird ringing to start off the day.

Yesterday we were using a new bird ringing site on the estate, after success at the A Focus on Nature event recently when several Lesser Whitethroats were caught, a bird I have only ringed once before. None were seen let alone caught yesterday, which is very odd. Perhaps they have started to migrate already, however it is still quite early for the Sylvia warblers to be on the move. Maybe they just moved to a new part of the estate.

We did catch many other warblers, however, the bulk of which were Chiffchaffs with 12 caught. One Chiffchaff showed very unusual moult: most of its coverts had just come out of pin. The pin of a feather is where the feather develops before coming out of pin and growing into a full feather. What makes the moult of this Chiffchaff strange is that usually moult is more gradual than the moult this Chiffchaff has shown:

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The highlight of my ringing morning was catching my first Sedge Warbler. This was a very peculiar catch! That is because although there are a number of waterbodies at Knepp, no Sedge Warblers breed here. This individual was a juvenile, which explains it. At this time of year, juveniles are dispersing, leaving the sites where they hatched and grew up. Soon we might even be able to catch adults as they stream south to winter in Africa.

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Soon after the ringing we had to leave to a different area of the estate for a bee field trip which I was very excited about. It was organised by the Amateur Entomologists’ Society (AES). I attended a similar one at Knepp last year which focused on grasshoppers and crickets.

When the field trip got going we were surprised at small numbers of bees that we were finding. Knepp Estate is a great habitat for bees with many different flowers which cater for the different tongue-lengths of bees. For instance, long-tongued bees such as the Garden Bumblebee (Bombus hortorum) are able to feed on Foxgloves and similar plants whereas short-tongued bees like the smaller solitary bees can only feed on flat flowers such as mayweeds and daisies. There are also lots of great nesting habitats for bees, such as fence posts, old lightning-stricken trees and farmyard walls. So why were the bee numbers so low?

The two most likely reasons are due to the weather. On the day it was very cloudy and dull, poor weather for bees to be out and about as they need to warm up in the sun before they can fly. Also, it has been a very poor season as a whole for them. June was a very wet and cold month, severely hindering the opportunities where bees could go out and collect pollen and nectar.

Despite the lack of bees, invertebrates of many other orders were well-represented and we spent time recording and marvelling at those as well between looking for and at bees. One thing that we all noticed were the incredible abundance of Cinnabar moth caterpillars. Their foodplant is Ragwort, and there are thousands and thousands of them at Knepp. In fact, it is the most abundant plant by quite a long way and most plants seemed to have several caterpillars devouring their foliage. Many plants were completely devoured apart from their stem and we found instances where a group of caterpillars had munched their way through one ragwort plant and had moved to another.

When it became particularly cloudy and there were no bees in sight, I became especially interested in finding grasshoppers following the field trip last year. Ralph Hobbs led the event last year and was here again this year and together we found quite a few. We noticed that on the inside side of the ‘thigh’ of the back leg of the Lesser Marsh Grasshoppers we caught there was a dark mark that we also found on Field Grasshoppers. Meadow Grasshoppers are the main confusion species for the Lesser Marsh Grasshopper and they seem to lack the dark mark on the leg. Ralph and I reckon that we have found a new identification feature to separate these two similar species, however more specimens will have to be caught and looked at before we can say that the dark mark is a completely reliable separation feature.

We stopped for lunch at a good site, it seemed. After I had finished my lunch I went exploring in the general area and there were lots of interesting creatures to be found. There were a large number of marsh flies (Dolipechidae) on and by a large muddy puddle, the species is easily recognised by the white tips to the smokey wings. These white tips are especially prominent in the males, which use them to display to the females. It is quite entertaining to watch, especially when a female rejects a male!

Surrounding the lunch site there were many willows (Salix sp.) and some large Oaks. This is great habitat for Purple Emperors, so we kept our eyes peeled.  I had already seen a couple a few weeks ago (blog post here) but I wouldn’t mind seeing another! Amazingly, I didn’t have to wait very long, I was kneeling down looking at a large Toad that had somehow found itself beneath a tight stone when I heard ‘Purple Emperor, just landed! Purple Emperor, just landed!’ coming from down the track. Of course I leapt up and ran towards where the exclamations were coming from. Some of attendees of the field trip were looking confused as our leader, Josh Nelson, tried to point out the magnificent butterfly to them. It was surprising how difficult such a large and impressive butterfly was to spot! The reason was because it was side on to us all, therefore we could only see a sliver of black and white against the oak leaves behind it. I must admit that it did take me a while to find it but once I did I was attempting to show others the butterfly which proved to be a very difficult task, although they all got onto it eventually. There it remained for a while before a ‘Purple Hairstreak’ (definitely not our leader Josh!), flushed it from the oak leaf it was sitting on. We were able to get our best views then however, as it fluttered over the nearby sloe bush and out of sight.

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See if you can spot the Purple Emperor!

So, when everyone was ready we decided to leave the area to see if we could find some bees, although that didn’t really go to plan. We actually only walked approximately 5 metres before we stopped again! This time we heard the calls ‘Purple Hairstreak, landed! Purple Hairstreak, landed!’. Once again, I rushed towards where a group of people were leaning over peering at something on the track. There, on the bare dirt, was a beautiful female Purple Hairstreak, with patches of stunning iridescent purple on the wings. This was easily the best view of a Purple Hairstreak I have ever had. Before I have only seen these small butterflies up at the tops of hedgerows or flying several metres above the ground. So what was this Purple Hairstreak doing on the ground, exposed and with its eyecatching wings open for all to see? It was as if it was saying ‘come eat me, I’m tasty’! Closer inspection revealed that she was indeed pregnant, and appeared to be very weak because of that. After obtaining some quick photographs we managed to get the hairstreak onto someone’s hand and Ralph poured some of his (non-alchoholic!) elderflower cordial onto his fingers. To our delight, the butterfly’s proboscis came out and it started to feed on the cordial! It soon gained energy and we placed it on part of a nearby oak tree which would catch the morning sun and where it would hopefully lay its eggs. Below are some of the photos I managed to take of this beautiful butterfly.

 

Soon we did move on, however, and now that we had our eyes in, we began to spot some more bees and other wildlife. One of the richest habitats of Knepp Estate is the grassland which is peppered with some scrub. On the sandy track through the grassland there is plenty of mayweed, a flower that is similar yet much larger than daisies. There were a few small dark bees, although however much we tried we were unable to catch any to identify them. The track was also riddled with some small circular holes, which were the nests of these small black solitary bees. Eventually, eagle-eyed Josh spotted one on the ground by its nest and swiftly potted it so that he can identify it back home.

The nests in the sandy soil gave us another idea for why there were few bees about. Perhaps the unnatural number of cows, pigs and deer on the estate were constantly trampling on these nests and destroying them. That might be one downside to the rewilding project, although it is restoring habitats to what they were like in prehistoric times, so perhaps bee numbers were this low millenia ago?

Our final stop before heading back to the car park was the outflow of mill pond. The edges of the outflow were rich in aquatic and water-associated flora such as Purple Loosestife, Yellow Loosestrife and Water-plantain. Josh told us that there was a bee that has specialised to exploit Yellow Loosestrife. Unsurprisingly it is called the Yellow Loosestrife Bee (Macropis europae) and it collects the oils from the Yellow Loosestrife flowers to water proof its nest. This allows it to nest in very wet places where other bees are unable to nest. Just as Josh was saying this, Ralph called ‘is this the bee?’. Josh potted it, had a look at it and confirmed that it was the bee! Amazing! This bee is easily identified by its distinctive black and white hind legs.

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Well, there wasn’t a huge number of bees at Knepp that day, although I really enjoyed talking to other naturalists as well as recording other wildlife that I came across. I can’t wait to visit Knepp Estate again!

The Emperor of Knepp

My Pan-species List is going along quite nicely and I think I will comfortably reach 2000 species by the end of the summer holidays, which is my target. However, I haven’t added another new butterfly species for a very long time. So on Tuesday, that is what I set out to do.

Knepp Estate near West Grinstead is one of the best places in Sussex to see the elusive Purple Emperor butterfly. Purple Emperors spend most of their time in the canopy of large Oak trees and there are many huge trees at Knepp, which also makes the estate good for saproxylic beetles. Saproxylic beetles are beetles that depend on dead or dying wood. Also, due to Knepp being part of a rewilding project, there is lots of dung about. Rewilding is where you take a location and try to restore it to the state that it was in many centuries ago. This involves using substitutes for wild boar (Tamworth pigs), aurochs (long-horn cattle) and other animals. Dung is good for Purple Emperor butterflies because they can harvest moisture and nutrition from it.

Apparently, to entice Purple Emperor butterflies down from the canopy, you need a banana and some fish paste. On Tuesday we chose fish paste, and we spread some on a slice of bread. After we had walked down a nice track to get to the Purple Emperor hotspot in the centre of the estate, we climbed up onto a tree platform and I unwrapped my fish paste bread. It wasn’t long before the flies began to arrive, but Purple Emperors were no where to be seen.

The weather conditions were far from ideal for the Purple Emperors. It was dull and very windy, there was no sun to warm them up and at the tops of the trees even these very large butterflies would have difficulty flying. However, we kept searching, walking along rides where we hoped the butterflies would show. We were just about to head home when the sun miraculously came out from behind the clouds. It immediately warmed up but we didn’t think it would last for long. We carried on walking down the ride when I nearly stepped on a long black thing. To my surprise it exploded from the ground just beneath my looming foot and flew towards the hedge on the side of the ride. I had nearly stood on a Purple Emperor! I hadn’t noticed it because its wings were closed making it look like a black twig from above. It wasn’t the best of views, but I had seen a Purple Emperor!

Sooner than I thought, it came back and landed on the track, where it probed the ground with its proboscis. It was picking up minerals from the dirt that it wouldn’t be able to get in the oak canopy. As it spends most of its time in the trees, it doesn’t feed on flowers which is very interesting. Instead, it most commonly feeds on the honeydew that is excreted by aphids and also sometimes on sap. Another interesting point about the Purple Emperor is that they are sexually dimorphic, which means that the males are different to the females. The males are much more beautiful and have a brilliant purple sheen when the wings are at a certain angle to the sun. However, the female is larger, dull brown and never has the purple sheen of the male.

While the butterfly on the ground was picking up minerals, I spotted a second butterfly flying around at head height. However, it was too wary to come down and retreated back to the canopy. The male on the ground was also flighty, but I did manage to get a few photos from a distance:

So, that is my 33rd butterfly species. Which butterfly will be next on my list?

Hedgecourt Invertebrate Survey: Part 1

I am very lucky to live within walking distance of a great Surrey Wildlife Trust reserve in South Surrey near the Surrey-Sussex border. Hedgecourt Nature Reserve is quite a small reserve, but it contains a mix of habitats. It is situated on the edge of Hedgecourt Lake, so that you can get a good view of the open water and the river that feeds into it runs through the nature reserve, creating a few stony streams too. There is a lot of marshland on the reserve, some open and some with tree cover. The woodland near to the lake is almost always flooded, especially so after rain when the lake level rises. This creates a fantastic habitat and I keep saying that it resembles the Florida Everglades in some places. I keep expecting to see a snapping turtle rise up from the murky water! There is also lots of dry woodland – interspersed with many small ponds – which attracts birds such as Nightingales.

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It is usually much wetter than this!

This year I have been given permission to conduct a relaxed invertebrate survey of the reserve. The wardens were very happy to have a free survey take place, they haven’t had one in quite a few years. My target number of species is 1000 by the end of the year but I’ll have to work quite hard to get to that figure! On my Pan-species list I barely have 1300 species, and that includes fungi, birds, mammals and plants!

So far this year I have made a few visits, mainly mopping up the common species before I get weighed down by the bizarre beetles and fantastic flies! Most were in the first winter period (January – March).

However, I have made one April visit so far this year. The walk through the reserve started off well. I had just passed the entrance sign when two Brimstone butterflies flew past across the marsh. A Buff-tailed Bumblebee clumsily flew in front of me and a Peacock butterfly erupted from the path ahead. There is a patch of new iris shoots coming out in the first marsh and I noticed small dark things on them when I walked past. At first I thought they were just holes in the leaves but on closer inspection I saw they were very small beetles. I tried to get one in the pot but it vanished – characteristic of a flea-beetle. One moment it’s there, the next: Whoosh!

When I got home I searched ‘flea beetle on iris’ on Google. Lots of results came up, almost all resembling my beetle. Guess what it was called? The Iris Flea-beetle (Aphthona nonstriata)!

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This mating pair was more reluctant to hop away.

Just 10 metres further up the path the open marsh turned into the woodland marsh. I bent down to have a look at a large ground beetle that was scuttling across the path when another one, smaller, caught my eye. A third species, which I recognised as one I found the other day: Asaphidion flavipes, also ran out from under a clump of moss. This site is great for beetles, I thought! I ran through the first two beetles at home and the first I didn’t find too hard to identify. It was quite distinctive and it turned out to be Elaphrus cupreus. I’m glad we found this species as it is found in very wet habitats so the wooded marshland at Hedgecourt is perfect for it.

The second one was a bit trickier as it was small and there weren’t really any distinctive markings. I spent a quite a while puzzling over this beetle with The Carabidae (Ground beetles) of Britain and Ireland (Luff, 2007) open on my lap. Eventually, using a combination of appendage colour and pronotum shape, I narrowed it down to Bembidion properans. This is interesting as this species is usually found in drier areas, the complete opposite of this section of the path at Hedgecourt.

My favourite part of the reserve is along the river that runs into the lake. The vegetation has recently been cut beside the river, presumably to let new vegetation grow through. The sun was shining directly on this open patch and there was lots of insect activity. Some Lady’s Smock (Cardamine pratensis) was already poking through and on one flower I only just spotted a resting Orange-Tip Butterfly. My first of the year!

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There were also lots of flies taking advantage of the warm weather. Three hoverflies were noted – the very common Eristalis pertinax and Helophilus pendulus and the very-common-but-new-to-me Platycheirus albimanus (White-footed Hoverfly). I also saw a Bee-Fly hovering above the cut vegetation, I have seen many this year.

A bit further along the path, I walked out onto the boardwalk to see what was out on the open water of the lake. I was glad to see three Common Terns loafing about on the buoys, showing no interest in breeding. Maybe they had just arrived and were catching their breath! They were sadly the only migrants I saw besides 3 male Blackcaps and a Chiffchaff.

We walked back along the path and turned onto the boardwalk leading into the sheltered reedbed. I was hoping to see an early Reed Warbler, but I did see another Peacock and a Comma butterfly on the boardwalk. They were absorbing up the sun before it goes away again!

There are several old trees by the edge of the lake where the bark is peeling off. I looked under one of these pieces of bark and I found both Common Shiny and Common Striped Woodlouse. I haven’t really looked at Woodlice in great detail before so the Common Striped was a new species to me. It is good to get them both on the year list as I’ll certainly be more busy in the warmer months.

So, I’m currently on 42 species for the year. Only 958 left to go before I reach my target! Hopefully I can find some of Hedgecourt’s specialities before the year ends.

 

Ardingly: A Butterfly Haven?

Since Thursday the 13th of March, I have been seeing quite a lot of butterflies at Ardingly. The first butterfly I saw there was a Red Admiral, flying across the Headmaster’s Field towards a tree full of blossoms. The blossoms are why I think the butterflies go to Ardingly, every twig has at least one flower on it. I also saw a Small Tortoiseshell resting and feeding on a branch, one of two Small Tortoiseshells I have seen there. The second one I saw was trapped inside the chapel. The other butterflies I’ve seen at Ardingly have been 2 Clouded Yellows and 1 Brimstone. The reason I think Ardingly is a butterfly haven is because I have only seen 3 butterflies outside of Ardingly this year, a Clouded Yellow in our next door neighbour’s front garden and a Skipper sp and a Clouded Yellow in our back garden.