Mid-March Moth Madness

After a snowy delay, last weekend it seemed like spring had finally sprung and temperatures rose into double figures. Looking at the forecast for this weekend and into next week however, it looks like the wintry weather will return once again which is very odd for this time of year. I’m usually a fan of a bit of snow, but only at the appropriate times of year. So I decided to write this blog post to try and keep my spring feeling going for as long as possible, before the snow showers begin to move in from the east again.

Saturday night was the first time I have put my moth trap out this year. In previous years I have been a little more keen, with very little reward and sometimes even null counts at this early stage in spring, so I decided to hold it off until now. And with the Beast from the East only about a week gone, my hopes were not particularly high. Although I was in for a surprise.

Most of the time, I just leave my trap out for the whole night and check it in the morning. However, on the off-chance of something notable (or anything at all!) being in there, I decided to look down from my bedroom window just an hour or so after switching on the light. To my surprise I saw what seemed to be an Oak Beauty already within the trap, so I rushed down to check if there was much else about.

To my immense surprise, there were at least 20 moths flying around the trap and on the nearby house wall. Most were March Moths as well as several more Oak Beauties, along with a couple of Tortricodes alternella and a Common Quaker. Already we had recorded around twice as many moths as I usually get in an early-spring night!

I was more than keen to check the trap the following morning. Unsurprisingly, there were moths everywhere, with the final tally being 55! I would be happy with that in May or September, let alone the first half of March! I will run through a few of the stand out highlights:

Small Brindled Beauty

This was the rarest moth that I caught last night, and the second time I’ve caught this species, the previous occasion being early March last year. It is most common in southern England, becoming rarer further north although classified as ‘local’ – found in less than 300 sites nationally. The females of this species are one of many winter and spring species that are apterous – lacking wings. The females of many of these apterous species seem completely unlike most moths to me, although I’m yet to find one myself.

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Small Brindled Beauty

Dotted Border

This species is unique among the early spring moths as it is one of the few Geometrid moths out at this time of year. In my experience it is usually the Noctuids (such as the Clouded Drabs, Hebrew Characters and the Quaker species) that are the most commonly trapped, although the most abundant species caught during this night were the 18 Oak Beauties which is a slightly unusual Geometrid species. The Geometrids can be distinguished by the way they hold their wings; most Geometrids hold their wings out to the side whereas most Noctuids fold their wings over their abdomen.

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Dotted Border

This species can usually be identified by the row of dots running along the bottom of the wing which you can see in the photo above. However, it is a variable species throughout its distribution and there are forms which are very dark making the row of dots (the dotted border) very hard to see.

Clouded Drab

This species is quite common especially where its foodplant Oak is plentiful although, despite its name, it is can be really nicely patterned. It is another species that is really variable, with many colour forms. We caught three, one of them in particularly was particularly good-looking, with its pattern enhanced by the flash on my camera.

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Clouded Drab

Hopefully the upcoming cold snap will be the last of the winter, and spring will be allowed to continue unabated. I look forward to moth trapping further once it warms up again, hopefully we’ll continue with some good numbers!

Final Tally

  • Common Quaker 3
  • March Moth 9
  • Oak Beauty 18
  • Hebrew Character 4
  • Tortricodes alternella 2
  • Small Brindled Beauty 1
  • Dotted Border 5
  • Clouded Drab 3
  • Small Quaker 8
  • Chestnut 1
  • Brindled Pug 1

 

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Crosswise

This morning, for the second time this week, I was standing on a well-trodden track on the Surrey-Berkshire border looking up at a couple of pine trees. This track crossed a plain of moor-grass and heather interspersed with small clumps of pines, known as Wishmoor Bottom. Since late November a flock of Parrot Crossbills has resided here, part of a national influx of this rare species.

The influx started with a large flock found on the Norfolk-Suffolk border, at Santon Downham. The numbers there peaked at an incredible 42 on one day, which is possibly the highest number ever recorded in the UK. Wishmoor Bottom was then the second site to host the Parrots, with slightly lower numbers remaining around a constant maximum of 16. The Derbyshire-South Yorkshire border was the next county boundary to be treated to Parrot Crossbills, with the forest around Howden Reservoir holding about a dozen. Most recently, 3 turned up at Broxbourne Woods in Hertfordshire (just inside the London boundary!) a few days ago.

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The Parrot Crossbills’ favoured tree in the drizzle

Influxes such as this one we are currently experiencing – I wouldn’t be surprised if further flocks are found – are mainly caused by a dearth of food in the species’ usual ranges. The Hawfinch invasion that’s in the news at the moment is most likely caused by a lack of beechmast and other tree nuts in continental Europe, with the crossbill invasion probably due to a poor crop of pine cones in Scandinavia.

After a long drizzly walk from the car park to what appear to be the crossbills’ favoured trees, we waited patiently for about an hour to see if the crossbills would show up. In that time a few other birders joined us; then we received a message through Rare Bird Alert that there were 16 Parrot Crossbills present on-site, right where we were standing. There were no other birders in sight!

“Someone must be having a laugh,” one birder said; we probably would have found it more humorous if we had by then actually seen the birds.

We were just about to split up to search the other clumps of trees spread out across the Bottom when my mum and I spotted a small group of birds fly towards us and alight in the tree directly in front of us. Most dived right into the needles of the pine, although one remained perched in clear view for a few seconds, enough for us to identify it as a Common Crossbill. That was good news, at the other sites where Parrot Crossbills have been present, they sometimes form mixed flocks with Commons.

Once the crossbills within the tree had surveyed their surroundings to make sure there was no danger, they set to work extracting the seeds from inside the pine cones. This made them more visible, and we were able to see that there were indeed Parrot Crossbills within the flock! Over the next hour I was able to watch them incredibly well. Although crossbills have a habit of staying firmly out of site within the dense branches, during the time we watched them there was always at least one on show.

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The above photos show the red-colouration of male crossbills, the females being a paler green colour. They also show the fascinating bill, with the lower mandible curving upwards on one side of the bill and the upper mandible curving downwards on the other side. It is unclear what determines the side on which each mandible curves, although the numbers of birds with mandibles curving each way seems to be equal. A crossbill feeds on the seeds within the cones by inserting its crossed bill between the scales and opening them and extracting the seed inside with its tongue.

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A female tackling a cone

Crossbills are by no means showy birds, so it was a real Christmas treat to be able to see this flock so well. Fingers crossed the influx continues and more flocks are found, possibly even closer to home!

Lover of a lonely mountain (or London reservoir!)

When I awoke on the morning of the 25th November, I had no idea that American Horned Larks existed. So just before breakfast, when I checked the notifications on my phone and saw “Horned Lark still present 8am” I thought that the perilous auto-correct had struck once more. However, once I looked into it in more detail, I realised that this wasn’t just the product of a birder with cold and numb fingers.

I have to say that Staines Reservoirs is not the most inspiring birding location, which is probably why my parents have been unwilling to drive me there before. It is comprised of a North and a South basin, with a central kilometre-long monotonous causeway separating the two. Yet when I was dropped off at one end on the chilly November morning, I was quite eager to get to the other.

The news was negative when I first arrived at the far western end of the causeway, where most of the visiting birders seemed to be clustered. I began to scan the cold concrete apron on both sides of the causeway, to no avail after about 10 minutes. The resident Pied Wagtails were constantly distracting me with their calls.

It wasn’t long until negative turned to positive however. Alerted by a call that sounded almost fluty, I spotted a quite chunky small bird fly low over the causeway. The careful rush of the birders closest to where the bird had landed confirmed my suspicion that the bird had returned. For the next 30 minutes or so, the assembled birders had brilliant views of the the American Horned Lark on the northern side of the causeway, often venturing within 10 feet.

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The photos I was pleased  to have taken of quite a mobile bird show the features that separate this American Horned Lark from the more regular Shore Lark. Shore Larks are winter visitors to the UK, with usually around a hundred overwintering on the East coast. As their name suggests they are mainly restricted to the coast, so even a normal Shore Lark would have been a brilliant record for London/Surrey.

Eremophila alpestris is the species that Shore Larks and American Horned Larks belong to. Although some authorities split them into separate species, most recognise them as only subspecies. The species is actually split up into a massive forty-two subspecies by some authorities, which is what makes Horned Larks so confusing. The regular Horned Larks found in the UK (Shore Larks) belong to the subspecies flava. And although this particular Horned Lark is named as ‘American Horned Lark’, around twenty-one of these 42 subspecies are found in USA and Canada. This particular bird is considered to be either:

  • alpestris – the nominate subspecies, found along Eastern Canada and Eastern USA.
  • hoyti – found in Northern Canada, wintering in Northern USA.
  • praticola – sometimes lumped together with alpestris, found in South-eastern Canada, North-eastern and East-central USA.

Luckily, and unsurprisingly for a bird with so many subspecies, there are noticeable differences between the British flava and the American subspecies listed above. The main ones are:

  • The extent of the yellow on the face is much less than in flava (as the name suggests, flava translating as yellow, golden), with a completely white ‘eyebrow’.
  • The flanks and overall colouration are much more russet than the pale-brown colouration of flava.
  • More obvious breast streaking than flava.

So although at the moment there is little doubt that the Horned Lark at Staines during the last week of November was of an American origin, the challenge of identifying it to subspecies still remains. Luckily however, if the Horned Lark Eremophila alpestris is split into different species, it is likely that all the American subspecies will remain as E. alpestris and the British subspecies will become E. flava.

A nice article to sum up the proposed splits of Eremophila alpestris can be found here: http://birdingfrontiers.com/2014/02/06/horned-lark-not-one-but-six-species/

Oh, and if you were wondering about the title of this blog post, Eremophila alpestris roughly translates from Latin to ‘lover of a lonely mountain’ – a reference to the breeding habitat of most of the subspecies!

References
https://www.hbw.com/species/horned-lark-eremophila-alpestris
https://en.wikipedia.org/wiki/Horned_lark#
http://birdingfrontiers.com/2014/02/06/horned-lark-not-one-but-six-species/
http://www.xeno-canto.org/species/Eremophila-alpestris

Moth Night 2017

The nights of 12th, 13th and 14th October were moth night 2017. You may think that dates so late in the season may not be great for moths, however there is still a surprising amount of diversity on the wing, including scarce migrants.

I put my MV light trap out on the Friday night, and I too was actually quite sceptical about catching many moths. Although my garden regularly attracts upwards of 200 moths a night during the summer months, it is far less reliable in the autumn and winter compared to other sites, for an unknown reason. However, I was in for a pleasant surprise.

Checking the trap at 7am, I could instantly see that it was much busier than I was expecting. The wall of the house near the trap was carpeted with Red-green Carpet moths, one of the most attractive Geometrid moths (the carpets, pugs and waves). There was a Snout moth on the white sheet beneath the trap, a Black Rustic in a gap between the patio tiles, and within the trap itself was my number one target: a Merveille du Jour.

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This was the first Black Rustic I have ever caught, which is overdue as they’re not an uncommon autumn species.

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This Red-line Quaker, named after the red line at the end of the forewings which is more obvious in real life, was a nice addition to the catch. Its cousin the Yellow-line Quaker is less commonly attracted to light and is best found by searching Ivy flowers after dark.

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This rather dull-looking moth is a November Moth. There are two species of November Moths that are very similar and can only be separated by dissection, the November Moth and the Pale November Moth. Therefore most people record them as ‘November Moth aggregate’.

Whoever named the Merveille du Jour (translated from French as Marvel of the Day) was not over-exaggerating. This species is often regarded as the holy grail of autumn moth-trapping; its exquisitely detailed markings and colouration are hard to resist. I’ve only caught one previously, so I was ecstatic about this!

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Another highlight was a Barred Sallow moth, one of those species where you can easily tell what it is supposed to be camouflaged as. It has patches of russety-brown and warm yellow, that perfectly match the colours of autumn Birch leaves. It’s certainly an effective disguise, which must have taken millennia to perfect.

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To finish off this blog post, I will leave you with a video of the Merveille du Jour. In the video, you can see that it is vibrating its wings. As moths are nocturnal, they cannot get direct energy from the sun (although they do get indirect energy from the plants that they eat), so they have to shiver (like humans do) to warm up their flight muscles. I used a lower shutter speed for this video, which appears to slow the vibrations down and they are shown as a ripple through the wings.

If you are viewing the email version of this blog post, the video may not show, so I would recommend visiting the site directly to watch it.

 

Don’t worry – all moths were released unharmed!

Moth #300

After my recent trip to Portland Bird Observatory in Dorset, I added a fair few nice moth species such as the rare Scarce Bordered Straw. Then, following a couple of new additions from my garden light trap, my moth life list was left on 299. I was very close to a big number!

To be honest, I wasn’t expecting my 300th species until I next put out the light trap which would be in another few weeks. However, it was much sooner than that and very unexpected! My mum let me know that she had found a large moth on the wall, my first thought was ‘probably just another Large Yellow Underwing’ as they are very common at this time of year.

Although when I saw it I was quite surprised! It was indeed very large but definitely not a Large Yellow Underwing as I had expected. The abdomen was projecting beyond the wings, which were sandy-brown with black dots and markings. I was able to get it in a pot and with the help of my Concise Guide it was identified as a Bulrush Wainscot, Nonagria typhae.

It is widespread in the British Isles, but usually only encountered in suitable habitat. For the Bulrush Wainscot, this is reedbeds and marshy areas. We don’t live in a marshy area (or a reedbed!) however we do have some in our local nature reserve, Hedgecourt. The larvae of the Bulrush Wainscot feed inside Bulrush (Typha) stems which has only recently started to really colonise Hedgecourt and is greatly outnumbered by Common Reed (Phragmites australis). The very helpful website UK Moths also says that this species can sometimes wander quite far away from suitable habitats, so we can’t be certain that my moth came from Hedgecourt.

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The Bulrush Wainscot that I found inside my house.

Every species is bringing me closer to my Pan-species Listing target of 2000 by the end of the year. I need just over 200 more species to reach this tough target, so every species counts!

It’s Popping Hot

Some people find plants boring. However, they are very clever. How can a plant be clever? Through evolution, plants have developed many fascinating ways to survive and thrive.

The key to a plant’s success is largely in the seed dispersal technique. Without a way to disperse seeds, plants would not be able to colonise new suitable habitat and spread. Therefore plants have learnt to be ingenious in their methods of ensuring the future of generations to come.

Yesterday afternoon I was walking through my local farm when I heard a few pops coming from the vegetation beside the path. At first I thought they were the calls of a grasshopper or a cricket, but definitely not a species I had heard before. I stopped and waited to see if I could hear anymore. I did, and this time I thought they sounded like click beetles, but why would so many be clicking at the same time? I was puzzled by this strange sound until, accompanied by a pop, I saw a quick movement out of the corner of my eye. I looked closer to where the movement had come from but I couldn’t see anything that I thought could have made the sound, just a patch of vetch. Then I realised that the sound was coming from the vetch itself!

Vetches are plants related to peas, they have pods like peas although usually much smaller. The pods begin green, the same colour as the leaves, and then as they mature they turn darker until they are brown. Plants in the pea family often have pods that pop, which is advantageous to the plant as it is a great method of seed dispersal. This method ensures the seed is enough distance away from the parent plant to prevent overcrowding.

Before I witnessed the popping of the seed pods yesterday I had no idea how it actually worked. How did the pods pop? I have done a bit of research and what I found out was fascinating. On hot days like yesterday the seed pods dry out, aided by the dark colour of the mature pods in some species which absorb heat. During the drying process forces build up inside the pod until it reaches a point when the pod explodes. In most pods there are two lines of weakness running along the pod, and it is here where the tensions which are set up in the wall of the pod cause the pod to explode. Similar to when a pulled spring is let back, the two halves of the pod curl back at lightning speed which flicks the seeds out of the pod!

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These two pods are still green and have not dried enough to pop.

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Two seed pods which are ready to pop! They have dried in the hot weather and turned brown.

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Two freshly-popped seed pods, showing the two halves of the pod

 

Golden Robber

Diptera, the true flies, are not one of the most glamorous groups I must admit. However, they are one of my favourites because of the sheer diversity of shapes, sizes and colours. I recently added my 100th fly species to my Pan-species List, a figure I have been working towards for quite a while now. The fly species that I am writing about today was my 103rd.

Yesterday I went on another Hedgecourt Invertebrate Survey trip to try to add more species to my list. There was lots about and only about 10 metres into the reserve I was distracted by the many invertebrates I was recording. These included a White-legged Damselfly and a snipefly (Rhagio tringarius) that voluntarily flew into my net. I was so distracted that at first I didn’t notice a medium sized black fly that had landed on my hand. Annoyingly it was on my right hand, my camera hand, so I found it difficult to take a photo. Then I realised that it was strangely placid, and I coaxed it onto my left hand where I was able to photograph it.

The fly had its wings folded back, which made it look like a Bibio. However, when I blew the wings apart and off from the abdomen it clearly wasn’t a Bibio. It had a long abdomen with a ring of golden hairs between each tergite (segment). To identify it I posted the photo on the identification forum on the Dipterists Forum website. The Dipterists Forum is a society set up for the study of flies. The Dipterists Forum run regular field meetings, such as the current one in Canterbury, curate Diptera-related Wiki pages and a whole host of online forums and run recording schemes for different fly groups. I received an identification for my fly very quickly: it was the Golden-haired Robberfly.

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Before I saw this one, I hadn’t seen a robberfly for a surprisingly long time although they are very interesting insects. They belong to the family Asilidae, with about 5000 species worldwide. The alternative name ‘assassin fly’ is very appropriate as they are very effective hunters that tackle difficult prey like wasps and occasionally even dragonflies. They are very fast flying, allowing them to outpace most of their prey. They are also patient, sitting on a sunny plant or log waiting for suitable prey to fly past. Even robberfly larvae are formidable predators, feeding on other insect larvae and eggs beneath the soil.

This robberfly wasn’t the only interesting invertebrate I found on my survey trip. I also found two caterpillars that I have been wanting to see for a long time: Mullein Moth caterpillars. They are very impressive and, as the name suggests, they usually feed on Mullein. However, some other plants are sometimes also fed on. I found mine in a habitat I really wouldn’t expect to see them in. I have never seen Mullein growing in Hedgecourt at all… let alone a wet reedbed! Still, there they were, a pair of them. They were large, well grown, and stunningly coloured.

If they weren’t feeding on Mullein, then what were they feeding on? Water Figwort has been recorded at Hedgecourt, and is apparently a known foodplant. Unfortunately at the time I didn’t note down what they were feeding on but I will look to see if there is any Water Figwort where the caterpillars were feeding the next time I visit.

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