Friday, 31 December 2010

2010: Year of the Auk?

As the year draws to a close, we are preparing for an Edinburgh Hogmanay celebration to see in the New Year. For me, 2010 has been year of the auk with a couple of trips on the Pacific from Monterey and San Francisco more than doubling my tally of auks, as well as seeing the usual suspects off the Scottish coastline. The auk highlights of the year were Tufted Puffin, Cassin's Auklet and Pigeon Guillemot (among others) at the Farallon Islands, California, and a great passage of Little Auks at Barns Ness in early November.

Of course, tonight is the night that birders all over the world will be toasting birds just like these...

Should auld auk-uaintance be forgot, and never brought to mind?
Should auld auk-uaintance be forgot, and auld lang syne?

For auld lang syne, my dear, for auld lang syne, we’ll tak a cup o’ kindness yet, for auld lang syne.
All the best for 2011.

Sunday, 26 December 2010

Feather de-pigmentation in Hooded Crow

Birded at Bull Island, Dublin, yesterday lunchtime in astonishingly picturesque weather conditions. Not sure there has been such a complete carpet of snow here in late December for many years. As always, the birds were excellent with plenty of Pale-bellied Brent Geese and Pintail along with the usual selection of waders and wildfowl - such an excellent city birding site.

One of the highlights for me, after recent posts, was a Hooded Crow showing feather de-pigmentation! Plenty of other species in this shot to give a flavour of the diversity at this site.

Here are a few more shots taken at the Bull Island causeway.

 Meadow Pipit finding little in the snow - it was foraging on thistle heads instead.

Belfast and Dublin

Saturday, 25 December 2010

Not a good day for turkeys

Saw these amazing birds on the road to the Lawrence Hall of Science in Berkeley in April. Feeling a little sorry for them now as we are about to tuck in to one. All the best to you all and season's greetings.

Are these Californian birds on my list? See for the full background to whether the CA turkeys are tickable. Personally, I thought that any bird large enough to cause me to take evasive action on a hairpin bend is worth seeing, truly wild or not...

Friday, 24 December 2010

Black-headed Gull variation

I took a few photos of Black-headed Gulls at Stranraer, Dumfries and Galloway. Most were cracking adult birds and they looked stunning.

The bird below is a second winter (2CY), judging from the black leading edges to primaries 9 and 8. What is unusual about this bird is that its five outer primaries are white (P6-10) along with the associated greater coverts and some of the smaller coverts as well. Normally only P7 to P10 are white. I know that some of the more eastern Black-headed Gulls can show this feature, so I wondered whether this could be a sibiricus bird. Not very likely, perhaps, but the weather at the time was well below zero... Maybe white P6 is a normal variant in ridibundus - anyone know?

(See this thread at Gull Research for comment on this bird, which suggests this is within normal but as yet undocumented variation for ridibundus)

Thursday, 23 December 2010

Calaveras Warbler: early seasonal present

It is the season for giving and receiving gifts, yet I was surprised to receive this armchair tick only yesterday. I photographed this bird in the Joshua Tree National Park in April. At the time it was a western form of the Nashville Warbler - a wood warblers 'species' with two highly separated (allopatric) breeding populations in eastern and western North America. Yesterday I read in this thread that despite the similarities in plumage between these western and eastern populations, the western birds are actually within the same clade as Virginia's Warbler, so it looks likely that these birds will be redesignated as a taxon at species level, and the name would likely be the Calaveras Warbler. In this shot the paler belly of the Calaveras Warbler is probably recognisable, certainly it seems more extensive than the bellies of the Nashville Warblers that I saw in the tree tops of the ramble in Central Park, New York, in 1996. Hmmm... must get back there for another look! Anyway, my thanks to those hard-working molecular biologists for the early present.
Another subspecies that has recently been resurrected to full specific level is the Audubon's Warbler. This spilt, from the eastern Myrtle Warbler, was officially accepted by many earlier in 2010 (for more details see Here is a shot of a male Audubon's, also at Joshua Tree, cunningly showing off its extensive white undertail and yellow throat.

For the beauty and contrast of their plumage patterns, these wood warblers have to be my favourite group of birds on the planet. Many others are of this opinion, though in fairness they probably tend to live in the Americas... I have a slight disadvantage in being based this side of the Atlantic. An interesting revision of the taxonomy of the various species of wood warblers can be found here

Wednesday, 22 December 2010

Winter conditions

The winter conditions are biting hard here in Edinburgh. A frozen pipe at the back of the house is slightly inconvenient, but nothing compared to the hardship the local wildlife must be suffering. Here are a few pictures taken today around the Pentland Hills, south of Edinburgh and near West Linton, in the Borders.

Red Fox (left) and Brown Hare (right) tracks in the snow.

Tuesday, 21 December 2010

Wing-flicking behaviour in the Blackbird

I photographed this Blackbird in a hedge at the Hermitage a couple of days ago. A smart male, like many of the birds along the burn, it seemed unconcerned by my presence, but as I fired off a couple of shots it wing-flicked.
The wing-flick, which is caught in the shot to the right, is a rapid extension of the primaries, of one wing in this case. The bird probably uttered a soft alarm type call simultaneously, but I can't remember for sure.
Now, this isn't an uncommon behaviour, but it is one that in the past I had dismissed as an indication of the bird being 'caught in two minds' - like it can't quite decide whether to flee or not. This time, though, I had a couple of images to study on the camera LCD, and the images reveal what appears to be a very deliberate and controlled behaviour - the bird is clearly moving one wing only, and does not appear to be preparing to flee. Also, the wing that is being flicked is the one that very visible from my viewpoint. The penny dropped - the wing-flick is a pursuit-deterrent signal... 

A pursuit-deterrent signal is a communication between a potential prey animal and its potential predator. In doing so, the prey individual makes itself more obvious to the predator, but in doing so it communicates that the predator has been spotted, has lost the element of surprise and if it continues its pursuit is unlikely to be successful. 

Notice that this pursuit-deterrent signal also appears to be an honest signal - that is, the bird is showing off the quality of its wing feathers as well as its speed of wing movement - the very features that are going to be utilised in any escape attempt. A sharp-eyed predator would end up knowing it has been spotted and also have it rammed home that this prey is not likely to be caught. 

I am not aware of any studies of this behaviour in thrushes, but it seems that the behaviour has been studied in the Stonechat. This study found that although wing-flicking had been assumed to be a flight-intention signal, it generally did not precede flight. Instead, it was a signalling behaviour used during the establishment of territory and in the distraction of nest predators.

No doubt there are many examples of pursuit-deterrent signals out there. Here is one more, a Great Basin Fence Lizard, photographed in the Joshua Tree National Park, California, honest signalling using its push-up display. This was repeated rapidly several times to make sure that I got the message that this lizard had definitely been working out and was no push over! Notice that it emphasised the message by flashing a neon blue throat at the same time. For more honest signalling push up displays in lizards, see here.

Monday, 20 December 2010

More barred axillaries in 1CY Common Gulls

The hard weather conditions continue, so Brambling and Fieldfare were back in the garden today, and when I threw some lunchtime scraps out to the gulls a Skylark was calling as passed overhead heading coastwards.

As the gulls were close I concentrated on taking shots of first winter (1CY) Common Gulls. I was hoping to get a better idea of variation in axillary patterning. As it turned out I managed to photograph four first winters within a short period. All show some barring, varying from barring on a single feather to extensive barring. These birds were different individuals to the one in the previous related post.

Bird with extensive barring on axillaries

Two birds each with traces of barring on longest axillary (unclear on r-h bird)

 Bird with strong barring on at least a single axillary on each side

Sunday, 19 December 2010

Yet more adult Common Gull variation

With another blanket of snow appearing overnight, the Common Gulls were tempted back into the garden. While in general the gulls have not hung around for extended photo shoots, today they seemed a little more habituated, or desperate. This first photo shows some structural variation in these gulls - the left hand bird has a longer bill with a more pronounced snout than the much shorter-billed and rounder headed bird on the right. The left hand bird also had noticeably longer tibia than the other.

Another adult Common Gull in the garden today had extensive grey feathering on the upper back, nape and sides of the breast - a wannabe Soft-plumaged Petrel perhaps...
After looking back through previous days' photos, here is a similar bird from the 6th December.

Common Gull tug o' war

Cheese rind is clearly very popular...

Revisiting de-pigmentation

On a walk with the kids today, saw the same Carrion Crow showing feather de-pigmentation. It was in a group of five birds, three of which showed at least some signs of this aberration.

When I told the kids that this bird was showing signs of a probable dietary deficiency they looked at me as if I wasn't very bright and responded, "Well, feed it then...". A small handful of our nut and fruit mix later and the crows were winging off to eat or cache their new supplies.

Note that in the third photo part of the de-pigmentation resembles plumage of a Hooded-Carrion Crow hybrid, though it is likely that it is not indicative of any recent Hooded Crow ancestry in this individual but merely a symptom of the presumed dietary deficiency.

Bat-bird is back

The tail-less Common Gull flew over the garden again today with its odd bat-like flight. Seen previously here on the 8 December, I am pleased but surprised to see that it has survived at least 11 days without a tail in weather conditions that have ranged to the extreme. Maybe it is not quite such an easy target for predators as it might appear.

Although the pictures are not very clear, it does look as though the unusual flight action is putting additional strain on the integrity of the wing - the tips of the inner primaries do appear to be showing excessive signs of wear.

Adult Common Gull variation in P8 mirrors

This is a poor photo but it shows the wingtips of several adult Common Gulls. Note that of the three wing tips that are most clearly visible, all show a white mirror in primary 8 (primary 10 is the outermost primary). In this shot, one bird (facing with food) has a tiny triangular mirror in P8; the wingtip above this bird shows a larger more circular mirror; more interestingly, the wingtip of the bird with its back to the camera shows an extensive white mirror in P8. Note that on this latter feather, the mirror bleeds across the vane into the outer web and this extension appears as though it almost meets the white tip. Of course the dull light combined with movement of the wing may be exaggerating the shape of this mirror.

Having a dip at Gullane

Twitching does not really do it for me. Don't get me wrong, I like seeing rare birds and I love seeing stuff that I have never seen before. But for some illogical reason, I get more of a kick out of looking at pretty much nothing in the hope that something unexpected appears, compared to seeing something pretty rare but known to be there already. Of course, this illogical thinking meant that I drove straight past the Green-winged Teal at Aberlady Bay today. Twice.

Ironically, I was twitching at the time, although in a pretty low-key way. Darren Woodhead had reported a trumpeting Northern Bullfinch at Gullane yesterday. I have been looking for this subspecies in among the Bullfinches at the Hermitage area in Edinburgh ever since Northern Bullfinches were reported on the Northern Isles and down the East coast earlier this autumn. Having failed to find any locally, I thought I would pop along to Gullane this morning to try to see, and hear, this trumpeter. More of an aural than visual twitch really.

No luck, as it turned out, but there were plenty of birds in among the sea buckthorn, which was festooned with its outrageous berries. Fieldfares were very obvious, though shy, and three or four Woodcock added to the event, though they seemed to melt away once the first of a stream of dogs appeared.