Wandering wool-carder?

One of Britain's most spectacular bees (in my opinion at least) is not a bumblebee, but the wool-carder bee Anthidium manicatum, one of the Megachilinae which includes the leaf-cutters. So, when I saw one basking on a Geranium leaf during a welcome burst of sunshine a few days ago (it then moved onto common bird's-foot trefoil Lotus corniculatus), I had to take a photo - however, when I looked more closely, it was almost, but not quite, as I expected.

The wool-carder bee Anthidium manicatum

At first glance, it looks much like any other individual of this species, however the yellow markings are far more strongly developed than is usual for a British specimen - they are usually spots to the sides of the abdomen with some in the midline and partially joined to form weak bands on the rear segments as shown in many books including Baldock (2008). A clearly striped individual like this is more like a continental European specimen - indeed, an experienced hymenopterist from BWARS remarked that he had never seen an individual like this in Britain. So, is this just an aberrant specimen, or - and I shall speculate a little - might something else be happening?

In Britain, A. manicatum is only locally common in the south, especially SE England, and becomes scarcer as you look further north. Until 1993 it was scarce even in the SE, after which it began to expand its range (Edwards, 1997) and become common is some southern locations. This suggests that temperature is a key factor in its distribution and to me indicates that this is one of many invertebrate species expanding it range as a result of climate change. Its common name of 'wool-carder' referes to its habit of shaving the hairs from downy plant leaves (such as Stachys) in order to line its nest - possibly a behavioural adaptation to provide insulation due to a requirement for high temperatures.

Considering the colour pattern, this specimen (like those in continental Europe) clearly seem to display wasp-mimicry, while typical British specimens do not, or at least only weakly. This would be a clear defensive adaptation, so why do British specimens tend not to show it? One possibility is that the relatively dark colouration permits more rapid warming when basking  - certainly this individual was also vibrating its wings at intervals, a typical insect behaviour used to warm the flight muscles. If, further south in Europe, this aid to warming is outweighed by the benefits from defensive mimicry, then the clearer stripes might be an advantage. This leads me to consider three possibilities:

1. This is an aberrant individual with no further significance.
2. It is a vagrant continental individual.
3. It is a British individual and increased temperatures are selecting for stronger stripes.

Of these, #3 is the most interesting but also the most speculative and there is no way of knowing from a single sighting. However, I intend to watch closely - males are highly territorial (and may kill other bees) so might use the garden regularly - and would be interested to hear from anyone else who has seen a specimen like this in Britain.

Anthidium manicatum basking on common bird's-foot trefoil Lotus corniculatus

References

Baldock, D.W. (2008). Bees of Surrey. Surrey Wildlife Trust, Woking.
Edwards, R. (ed.) (1997). Provisional Atlas of the Aculeate Hymenoptera of Britain and Ireland. Part 1. BWARS/BRC, Huntingdon.

Red-breasted Goose in Hampshire: twice in one day

Yesterday, I took a trip to the area around Hook-with-Warsash Nature Reserve in Hampshire (southern England). This was mainly because, on a sunny day between bands of cloud and rain, I fancied a day out nature-watching - however I was also drawn by the reported presence of a Red-breasted Goose (Branta ruficollis), a rarity in Britain and not a species I'd seen before...

It's a sub-Arctic breeder (the Taymyr, Gydan and Yamal pennisulas of northern Russia), and usually migrates to eastern Europe (especially Bulgaria, also Romania and Ukraine, including the Black Sea coast), well away from here. However, occasional individuals do follow Brent Geese (Branta bernicla) - which breed in similar areas such as the Taymyr - further west and appear as rare vagrants. Interestingly, as they have no direct defense against predators such as the Arctic Fox (Alopex lagopus or Vulpes lagopus), Red-breasted Geese nest near birds of prey, especially Peregrine Falcons (Falco peregrinus). This means that the birds of prey protect the geese, while the geese can alert the birds of prey (who also suffer fox-predation of nests) to the presence of foxes. However, with land-use changes in eastern Europe affecting their few wintering sites and the ongoing effects of climate change on Arctic and sub-Arctic species and habitats, the Red-Breasted Goose, with a population estimated at somewhere around 38,500 globally are now classified as Endangered on the 2007 IUCN Red List.

So, there's a rare British vagrant species, endangered globally, just along the coast. What else could I do but have a look? It would be rude not to... The next decision was where to look. The area where it was reported covers a few miles of coast, as well as plenty of potential feeding fields slightly inland. A strategy was needed. Handily, two winters ago, me and a colleague did a goose and wader survey in exactly this area and so have a pretty good idea of where geese go at high tide, especially the Brent Geese which our target bird would most likely be with. So, we met up and headed for Chilling Cliffs just by the Solent Breezes caravan park. It's not where most reports were from, but it was a place we knew wildfowl used... and as we arrived there was a small group of 11 geese just offshore; 10 Brents and our Red-breasted Goose - result! Sometimes you just get lucky (helped with a little local knowledge) - a and although it's usually younger birds that get lost and migrate the wrong way, this one did have a full red cheek/head patch (some young birds do).

Result! Red-breasted Goose near Chilling Cliffs.

Our timing was lucky though as, about 5 minutes later, the small flock flew off - and we couldn't help but notice how similar the two species are in flight, once the patterns can't be seen - the same size, shape and movement, effectively the same 'jizz'. Still, we'd spent a whole winter tracking and recording goose movements in that area... so, via a brief (and unsuccessful) side-trip to see a Firecrest (Regulus ignicapillus) also reported locally, we headed to Hook-with-Warsash with its mix of coastal habitats, saltmarshes and fields. We started off looking at some arable fields where the winter wheat is popular with grazing geese. Nothing there. We then tried the saltmarshes - plenty of interesting species with about 12 species of waders using the high-tide roosts (including a close view of a 100-strong roost of Golden Plover, Pluvialis apricaria) - and headed along the coast until, about 3 hours after our initial sighting, we looked into a grassy field and there they were; about 150 Brents plus our vagrant Red-breast. never having seen one before, it was interesting to see that the books are right - despite the colourful pattern, it tended to blend in with the Brents and could be difficult to pick out, especially if seen from the rear when just a few stripes differentiate it.

A Brent Goose for comparison

Part of the Golden Plover roost

And so, a very successful bird-watching day, and a clear indication of the value of local knowledge - you can't guarantee wildlife, but you can improve your luck a bit. If you're out looking for this bird, the sites are (1) Chilling Cliffs - follow the path from the car park on the hairpin bend on Chilling Lane, and (2) Hook-with-Warsash - the field running parallel to, and on the seaward side of, Hook Park Lane near Cowes Lane. The map here should help.

Lastly, if you are interested in the topics of wildfowl and bird migration, you might like the following which should be quite affordable in paperback (both from the Collins 'New Naturalist' series):

• Cabot, D. (2009). Wildfowl.
• Newton, I. (2010). Bird Migration.

Enjoy!