Dunlin

Head to any coastal mudflats in the winter, and you are likely to see a whole host of wading birds, including Dunlin (Calidris alpina), Turnstone (Arenaria interpres), Sanderling (Calidris alba) and Knot (Calidris canutus). Dunlins are the most common of these winter waders and often feed in flocks, so where there's one, there's usually a whole lot more somewhere nearby!

Dunlins are small wading birds that have a slightly decurved black bill, black legs and a short primary projection. Their wingspans range between 33-40cm and they weight around 49g. As with most waders, Dunlins moult between their two plumages, a brighter, more colourful one for the breeding season, when they need to look their best, and a fairly dull, grey-brown one for the winter, when looks aren't so important. Using a combination of sight and touch, they feed on a variety of invertebrates, including insects, molluscs and oligochaete worms.

© https://adventuresinmothland.wordpress.com/2013/05/28/evil-scud/
Dunlin (Calidris alpina) in breeding plumage.

There are currently 10 subspecies of Dunlin that are officially recognised, however the taxonomy surrounding this species is very complex and often changing. Of the 10 official subspecies, 3 have been recorded in Britain: schinzii, alpina and arctica. The schinzii subspecies of Dunlin breed in the UK, with around 9,600 breeding pairs and winter in west Africa, while the arctica subspecies are birds that breed in Greenland and pass through the UK in autumn in small numbers. The C. a. alpina subspecies breeds across Siberia, all the way to northern Scandinavia and account for pretty much all of the Dunlins that winter in the UK.

At the end of February, the UK was struck by the 'Beast from the East', or as most of Northern Europe calls it, winter. This resulted in about a week of sub-zero temperatures and heavy snow here in East Anglia. The freezing conditions and snow cover caused many problems for wildlife, with many reports of dead birds across the country and East Anglian region. Waders were particularly vulnerable as they rely on being able to probe muddy areas to find food, however since the conditions caused widespread freezing, they weren't able to access their usual food resources for a prolonged period of time, leading to starvation.

Bowthorpe Marsh looking like a frozen wasteland

During the cold spell, some of my Ecology course mates and I tried to venture out as often as we could to do some proper winter birding. On 3rd March all our lectures were cancelled, so we made the most of it and spent all day out birding around Earlham, Colney, Bowthorpe and Threescore. During our travels we came across a pair of Lapwings, including this unfortunate individual, which had a large ball of ice stuck to its tail, preventing it from flying. We dutifully broke up the ice ball and then warmed it up for a few minutes, before releasing it to join its mate on the river. It was very bizarre to see, but I suppose it may have roosted on the edge of an unfrozen puddle, which froze overnight or something... I guess we'll never know.

Lapwing (Vanellus vanellus) with a large ball of ice attached to its tail.
Anyway, back to the topic of this post, the Dunlin. A few days prior to the Lapwing encounter, a few of us had headed out birding along the River Yare when we spotted a Dunlin at the water's edge. Dunlins are a decent bird for the UEA recording area, especially when they're on the deck like this one. It was nice to see, even if it did look a bit sorry for itself in the freezing conditions. Before we carried on our walk, someone made a joke about the Magpies that were loitering around... so to skip to the end, as we returned from our wanderings later that day, we decided to head back along the Yare to see if the Dunlin was still moping about. It was.

Dunlin (Calidris alpina) looking a bit sorry for itself, shortly
before it got taken by a Magpie.
However, a few seconds after we arrived, a Kestrel appeared out of nowhere and swooped down at the Dunlin, but didn't try to catch it. Unfortunately, a Magpie must have clocked what happened and made a beeline straight for the Dunlin, picking it up with very little struggle and carrying it off into the woods, where the commotion of many other Magpies could be heard. A sad end to a nice day's birding, although perhaps a fairly swift death from a Magpie's bill was a kinder end than potential starvation for the Dunlin...

A few days later, once the snow had melted and the ground had (mostly) thawed, another Dunlin rocked up on Earlham Marsh, where we enjoyed nice views of this more perky looking bird and the other UEA birders managed to see it as well.

Dunlin (Calidris alpina) looking a lot less moribund!

Further reading that may be of interest:

Holly Leaf-miner

Leaf mines are mainly caused by species of Lepidoptera (moths), Diptera (flies), Hymenoptera (sawflies, bees, wasps & ants), and a few Coleoptera (beetles), whose larvae feed within the leaves of plants. As the larvae feed and grow, they move throughout the leaves, creating mines. The mines created by these species are often very distinctive and, coupled with the fact that leaf-mining species tend to be restricted to a certain range of host plants, it is often possible to identify mines to an individual species.

The first step in working out a miner's identity is correctly identifying the host plant. Doing this normally narrows down the possibilities quite a bit and then you can identify which type of insect (order) the miner is from:
  • Lepidoptera normally make full depth galleries or blotches with single lines of frass (droppings).
  • Diptera mines are either lower- or upper-surface (or a mix of both), their larvae are maggots and they characteristically make twin trails of frass.
  • Hymenoptera mines are blotches rather than galleries and characteristically have extensive amounts of dark frass (compared to diptera mines). The larvae of Hymenoptera also have visible legs.

Phytomyza ilicis is a species of fly (diptera) whose larvae mine the leaves of Holly (Ilex aquifolium). P. ilicis is incredibly common and is the only species to mine Holly in Britain, making it very easy to spot and identify! It is abundant on the UEA campus, with P. ilicis mines visible on just about every Holly bush you come across.

Phytomyza ilicis leaf mine on holly

Snowdrops

The appearance of Snowdrops (Galanthus nivalis) in January is one of the first signs that Spring is just around the corner.

Snowdrops are a perennial flower in the Alliaceae family, alongside the garlics and daffodils. They can grow up to 25cm tall and are found in a range of habitats, including damp woodlands, hedge banks, churchyards. Although many people think of Snowdrops as a native wildflower, it is now believed that they were in fact introduced to Britain in the early sixteenth century.

Snowdrops are pretty neat little things and have a surprising range of uses too, including agricultural and medicinal applications...

Snowdrop lectin (carbohydrate-binding proteins) is an effective insecticide against species of Coleoptera (beetles), Lepidoptera (butterflies and moths) and Hemiptera (true bugs), and some research has suggested that introducing Snowdrop lectin to genetically-modified crops may increase the resistance of GM crops to insect pests. Snowdrop lectin is also being investigated due to its potential activity against HIV.

Galanthamine is an alkaloid found in Snowdrops which has been approved for use in a number of countries for assisting with the management of Alzheimer's disease, as well as being used in the treatment of traumatic injuries to the nervous system.

These delightful little plants are fairly numerous around the UEA campus, and are especially abundant underneath the conifers near the Sainsbury Centre.

Some of the Snowdrops (Galanthus nivalis) near the UEA Sainsbury Centre