Friday, 29 March 2013

Cuba 2: more endemics

A close encounter with the wary and retiring Blue-headed Quail-Dove, one of four quail-dove species we saw in a single morning at Zapata Swamp.
No less beautiful was this Grey-fronted Quail-Dove, seemingly an even shyer species than its congeners. This endemic was formerly lumped with Hispaniola's White-fronted Quail-Dove as Grey-headed Quail-Dove.
A Bare-legged Owl, one of two seen during the trip, plays peek-a-boo from the safety of its daytime roost. This endemic is the sole member of the genus Gymnoglaux.
Rather easier to find was Cuban Pygmy Owl, a diurnal and vocal species with plenty of attitude. Its presence often triggered mobbing behaviour in other birds in the vicinity, particularly warblers.
Cuban Black Hawk was split from Common Black Hawk by the American Ornithologists' Union in 2007 mainly because of morphological and vocal differences. The species seems to prey heavily on crabs.
The toughest endemic bird species we saw, Gundlach's Hawk is widely distributed in Cuba but rare. BirdLife International estimates the total population at just 270 mature individuals, hence its classification as Endangered.

Monday, 25 March 2013

Cuba 1: endemic birds

Cuban Trogon: the national bird, purportedly reflecting the red, blue and white colours of the country's flag.
It was a long time in the planning, but the preparation paid off and this month’s trip to Cuba proved to be a resounding success. Eight of us went with the primary aim of seeing the country’s endemic birds, and we were not disappointed: of 25 endemic species (according to Clements taxonomy), our 11-day jaunt netted good views of 23 and logged another as heard only. The only complete absentee, as with virtually every tour to Cuba, was the mythical and apparently nocturnal, swamp-dwelling Zapata Rail – almost unknown to locals, never mind visitors. Of course, there was much more to the tour than endemics, and the provisional group list is 174 species, including many regional specialities and numerous migrants. 

There are two subspecies of Cuban Green Woodpecker in the country: this is the widespread nominate percussus.
Rather more elusive was Fernandina's Flicker, a beautifully marked endemic which we rarely saw well.
I organised the tour through the excellent services of Andy Mitchell (no relation) and Havantour. Logistics in the country were faultless from start to finish, with the excellent Erik Garcia as our Cuban escort and assorted local bird guides at several sites. The only hitch was for two of our crew who flew via Amsterdam and missed their connection because of snow when leaving the UK; after an unexpected detour via Panama they arrived a day and a half late. The crew in full: myself, Dr Leo Batten, Neil Bowman, Trevor Ford, Gerard Gorman, Pete Lowman, Andrew Self and Dave Watson. Commiserations to Roy Beddard, who for unavoidable reasons had to pull out on this occasion – hopefully next time.

Zapata Sparrows of the subspecies varonai on Cayo Coco, off Cuba's north coast.
Some of the country's unique species, like Cuban Gnatcatcher, more closely resemble widespread counterparts elsewhere in the region. The crescent behind the eye distinguishes this species from Blue-grey Gnatcatcher.
For now, here are a few of Cuba’s endemic birds – the real specialities that every visiting birder wants to seek out. Some are tougher to find than others, but 11 days proved sufficient time to get virtually all of them on this occasion.

Male Bee Hummingbird - the smallest bird species in the world, but the biggest target for many visiting birders.

Thursday, 14 March 2013

Field guide revolution

An exclusive preview from the forthcoming Crossley ID Guide: Britain and Ireland, showing the huge potential that digital manipulation offers in selecting and combining a wide range of photographic images into montage plates.
Digital technology has unquestionably revolutionised birding – the very fact that you’re reading this on a blog is ample evidence of that. From journal-keeping to bird sightings, it has impacted on many areas that nowadays we take for granted – a far cry from birding’s back-to-nature origins as an outdoor activity borne of fieldcraft.

Of course, we wouldn’t have it any other way. The advantages are there for all to see. And now even traditional industries like book publishing are being transformed – not just behind the scenes through the application of cutting-edge technology, but now in the very make-up of the identification guides which are key tools of our trade.

Perhaps there’s no better example of this than the Crossley ID Guides. When the first in the series, the Crossley ID Guide: Eastern Birds, was published, it’s fair to say it divided opinion. Undeniably innovative with its photo-composite panoramic plates of birds in habitats, it was probably also a shock to the system for those who grew up with plates of painted figures aligned in rows opposite summary ID texts. Both approaches are valid, but with the potential of digital image manipulation almost unlimited, it’s clear which formula has more latitude.

From the imminent new Crossley ID Guide: Raptors.
The latest Crossley ID Guide, published by Princeton University Press, will aim to win over any who still remain sceptical. Raptors covers an ever-popular family, and though dealing with North American species it will have resonance with birders in Britain and Ireland too – even for those who haven’t yet enjoyed birding on the other side of the pond, a sprinkling of species including American Kestrel, Northern Harrier and Bald Eagle are known here as mega-vagrants, and of course Rough-legged Buzzard enjoys a Holarctic distribution, even if its chocolate-brown dark morph is undeniably Nearctic.

Following not far behind Raptors will be another Crossley ID Guide later in the year, and one which birders in Britain and Ireland will certainly be taking a keen interest in (left). Check the Birdwatch magazine website tomorrow for more news on that launch.


Monday, 4 March 2013

Unsolved mystery

Unidentified gull, Rainham, Greater London, 1 March 2013. Note the mid-grey upperpart tone, red orbital ring,
pink feet and pattern of black in the wing-tip extending to P5.
After the practical side of gulling, today it was time for the theory. A week ago I had arranged to visit the Natural History Museum collection at Tring, mainly to look at skins of Vega Gull Larus (smithsonianus) vegae. By extraordinary coincidence, however, three days beforehand I found an adult-type large gull at my regular larid patch of Rainham, Greater London, which showed several features suggestive of that taxon. Common sense dictates it is far more likely to be something other than a species never before recorded in Europe. But what?

The same gull showing the underwing pattern, with its show-through grey 'shadow' a good indication of the visibly darker grey upperwing than argenteus European Herring Gull (ruled out by wing-tip pattern and orbital ring colour).
In short, the answer is I don't yet know. Vega Gull should be possible to prove if seen well and documented with decent photos. But there are many unknowns to factor into the equation – especially hybrids. A key problem to me could be the far more likely option of European Herring L argentatus x Lesser Black-backed Gull L fuscus, and eliminating such a combination would surely be essential in ever confirming an adult Vega Gull in Europe.

The only shot I was able to grab of the bird on the ground, immediately on discovery and just as it was about to take off. In this over-exposed image the legs look paler and less strongly pink than they did in life. The white tertial crescent looks relatively broad here.
As can be seen from these photos, the Rainham gull showed a combination of darker grey upperparts, black on the six outer primaries, mirrors on P9 and P10, pinkish legs and red orbital ring, all potentially invoking thoughts of vegae. But are some (or even all) of these characters also theoretically possible in a hybrid or back-cross? It's difficult to say for sure as many reported European Herring x LBBG hybrids are merely identified as such on plumage traits, rather than being of known parentage. On photos of typical Vega Gulls, the legs appear more strongly pink (light raspberry perhaps). According to some of the literature and what I noted on skins at Tring, if there is a mirror on P9, it is more usually either on the inner web or spread across both webs, whereas on the Rainham bird it is on the outer web (at least on the right wing). And for Vega, perhaps the trailing edge of the secondaries should show a broader white margin? I'm not yet clear on that.

This shot gives a slightly clearer view of what's going on with the white mirrors on P9 and P10. Note also the faint dark mark near the bill tip, possibly indicating residual immaturity.
Intriguingly, however, the bird hasn’t finished growing its outermost primary – something that any likely parent species should have long done by the beginning of March. As has already been pointed out to me by one gull expert, the fact that it is still growing P10 at this time of year could be an indication of origin in the far north, as gulls from Arctic areas moult later than those further south. Vega Gull certainly has a later moult than European Herring Gull, and the Rainham bird's primaries with broad, well-preserved white tips again fit. The literature suggests that white sub-terminal markings in the mid primaries (P5-P7) might often form a so-called 'string of pearls', rather like Slaty-backed Gull L schistisagus, but on examining this feature on 21 skins from eastern Asia labelled as vegae at Tring, almost 40 per cent actually showed very narrow white crescents or even fainter borders very close to those of the Rainham bird (see below). On the downside, however, perhaps P8 in the Rainham bird is too extensively blackish in these photos compared to Vega.

Adult Vega Gull wing-tip lacking the white sub-terminal spots - the so-called 'string of pearls' - on P5-P7, instead having the faintest white borders separating the grey tongues from black tips. Almost 40 per cent of 21 vegae skins in the Tring collection had a pattern broadly similar to this. Photo: Dominic Mitchell © Natural History Museum.
Adult Vega Gull wing-tip showing much more obvious white tongue-tips on P5-P7. This was the commoner of the two vegae patterns in the Tring collection, though several skins were intermediate in this respect.
Photo: Dominic Mitchell © Natural History Museum.
What I'd like to establish next is if hybrids ever show such a similar pattern of white in the mid-primaries, and also the extent and pattern of black on P5-P7 (again more variable than I expected on the vegae skins at Tring). To that end, I'm very keen to obtain photos of European Herring x LBBG hybrids, ideally showing the open wing-tip pattern, and especially if their parentage is known. Please leave a comment here or contact me directly if you can help; equally, if you can provide informed comment from experience on this bird that one larid aficionado has already said "could well be a Vega", I'd like to hear.

* Thanks to those who have already commented privately and in person, and to Hein van Grouw at the Natural History Museum, Tring.


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