Spending the northern winter in the Caribbean sounds nice for us, we’d have the security blanket of our mothballed homes to return to, flick a few switches and on come all the amenities that we just can’t do without. Just down the road some more returnees are going through a similar process, albeit at a much more basic level; where to live and, more importantly, where to raise their family. The Piping Plovers came back, well the vanguard did, and I hope they get fewer worries this year. Unfortunately the cycle of ignorance regarding beaches and people will run again and some of the plovers won’t do as well as they should.
The plovers have some support, friends even, but not enough and the general public simply does not understand why they can’t walk the dog, picnic or even Geocache in a Piping Plover (or tern) breeding area. It is lack of understanding rather than malice but the end result is the same, a disturbed or even failed breeding season.
We might do better if there were big new signs, placed annually on each beach entrance stating “The Piping Plovers are back, all dogs on a leash, no vehicles on the beach, please stay out of zoned sections until…” and a date. Blunt and in need of back-up via hard-hitting penalties for transgressors true, the trouble is that the rest of society’s problems rate higher than the problems of a small bird and there is no money, nor apparent will by any level of Government to tackle the issues at present. For now we’ll have to rely on the good will of the populace in general and hope that the ignoranti give the beaches a miss this year.
That being said, they are back and these two posed nicely on Daniel’s Head Beach on March-30th. Unbeknown to us, another birder had seen one there on March-28th, I should have looked harder.
The tagged bird (E6) has been reported.
After seeing the plovers, Sandra and I headed out and about around the Blanche Peninsula. Our last two visits were birdless and, frankly, a waste of time but, if you don’t go you don’t find. On the way out we called into West Head, Newellton just to see whether there was goo coming out of the pipes attracting gulls (calm down). No goo but this moulting Common Loon sat still. I find the way the bill colours up interesting, it is almost as if it is being plated with sections of black steel.
On the way down Blanche it was not so inspiring. Would this be another 16km of ruts and bumps with nothing to show? At the very end we parked up in the rugged parking lot and came across a bunch of waxwings flycatching for insects. The light was behind them and even scoping didn’t reveal too much detail. Most were Bohemian with just four Cedars, the former a welcome find after being sparse in our area all winter. I waded a stream to get better light and managed a few images before the whole lot went seeking insects new. We had 40 Bohemians on the final count, now fingers crossed they head to Cape Sable Island where they would be even more welcome.
Speaking of Cape Sable Island, as I said in the last post I’m at the editing stage, well Sandra is, she’s the literate one. In researching the birds of CSI I have a total of 384 species that I’ll be including in a systematic list as part of the FREE guide. That is quite a total and it reflects well the importance of the location for birds.
It’s been a while since I posted a gull photo or two but I know most of you are avid larophiles and just love to look at pretty gulls. These images were from a recent trip to Meteghan in Digby County, NS, I may have mentioned the star Kamchatka Gull in a previous post. Well I also managed to snap a few of the other gulls around, not too many photos, comments made where applicable.
Interesting dark eyed Kumlien’s Gull.
Standard 2nd-cycle Kumlien’s Gull
Three Kumlien’s Gulls (Iceland but I’m sure you know that). The 1st-cycle is a lump of a bird.
A dinky looking adult Kumlien’s Gull, a female perhaps.
A regular adult Kumlien’s Gull.
A nearly Thayer’s Gull wing pattern, the dark and well-marked end of Kumlien’s.
Yes, it’s true, there are no gulls in this post. I had five applicants for a certificate of lunacy for the last post so I included it at the end for you to print off yourself. If you use a 3D printer it becomes a straight-jacket!
March is ambling out now, not a great month for movement on the CSI year list front though. The highlight was a White-breasted Nuthatch, don’t laugh, or perhaps it was the American Woodcock that gave less than stellar as it passed over the house, it was a Nova Scotia tick too so perhaps it shaded it.
Merlins have been a bit scarce this winter, in fact I suspect that we have had only two in the area since December of last year. On a windy and wet day this one hid behind a rock (unsuccessfully) on Daniel’s Head (who was Daniel by the way?).
Ducks have been slow to build in number and variety, unless you include Black Ducks that is. We have a couple of elusive Gadwall still and a pair of Northern Pintail have been 20m from the road just before the bend on Daniel’s Head for a week or so, here is the male.
Brants continue to arrive and their noisy gatherings late afternoon are fun to watch. I have yet to get what I’d consider good shots of them but sooner or later they will be obtained by the new lens.
We did a trip to The Cape a few days ago, it has many names, Cape Sable, Cape Island, Cape Light but I have resolved, after due consultation, to stick with The Cape. It was cool with easterly winds and the bird life fairly limited. This Snowy Owl, not the regular clean white male that commutes between Baccaro and occasionally CSI, but a different bird. We rather surprised it and it flew off out to see before heading for Ratcliffe at the west end of The Cape.
I missed three Harlequins that passed while I was walking the marsh looking for woodcocks and snipe but I did get the camera on Savannah Sparrows, the Ipswich type that have wintered in small numbers, now we are seeing fresh birds on their way north.
So there we are, no gulls at all, not one but… Next time I have some nice photos of dark-eyed Kumlien’s Gulls for you to enjoy and a possible hybrid too. Don’t worry, I’ll be sure to repost the certificate!
One last word, I expect to have the FREE e-guide to Birding Cape Sable Island published in the next couple of weeks. I just have a couple of loose ends to tie up and then it is yours, if you want it.
Until Swarovski add the much anticipated DNA remote sensor to their excellent range of binoculars, we’ll just have to continue to do things in the field ‘old school’. Not that DNA is of any use when it comes to birds, species yes, but not when morphology is more important for identification. Having the correct divergence of DNA gives a bird the hard currency of birding, the tick. Unfortunately it also means that distinctive forms that are readily identifiable in the field become ‘just a’ (fill in the blanks). So when Redpolls get lumped and the dollar hungry industries tear into their breeding grounds for gas, oil or other developments, it won’t matter, plenty of Redpolls out there, just ask the Song Sparrow form that used to breed in Florida, oh you can’t, it’s gone.
The point I’m clumsily making is that we should accord subspecies the same status as species, or risk losing them.
That cheery preamble is a stage setter because I’m writing about a sub-species, a form, a type of and, even worse, a gull. We have a truly great bird here in Nova Scotia at the moment, truly rare in North America, actually pretty cool to look at too so why the inertia from the birding public? True, it is stuck out in Digby County, a long way from the big city but, they do have paved roads, electricity, gas stations and coffee (The Sip Café, 19 Meteghan Conn, Meteghan, NS B0W 2J0) and a Tim’s, if you like that sort of thing. There are actually lots of birds there to look at as well, another seven species of gull for example, how full is your plate now eh?
I tend to write these things up a little differently so here goes. In January 1993 I saw a gull that I eventually thought might be a Kamchatka. I looked at many skins in the British Museum at Tring. I bought every book that illustrated presumed Kamchatka Gulls, even ones in Japanese which I still have yet to read! I also looked hard at Common Gulls. I’m going to use a different terminology for the three identifiable members of what was called the Mew Gull complex, it is now Mew Gull, Common Gull and Kamchatka Gull – the split starts here!
Just tidying things up a bit before we crack on. Mew Gull is predominantly a west coast bird in North America. Common Gull is essentially a European bird but one that is found regularly on the east coast of North America. Mew has been found in the same area but is distinctive enough to identify and so data exists to know which has occurred and where. I am unsure whether Common Gull has occurred on the west coast, I’d be surprised. At the eastern end of the Common Gulls range there is a big hole filled by another version, at present not really that easy to identify in the field. They are calling it Russian Common Gull, poor name, must try harder. We are going to ignore it here because it has no part to play in the story of the Meteghan Kamchatka Gull, none at all.
The Kamchatka Gull was found by Clarence Stevens Jnr who correctly identified it as a Mew Gull as, within our DNA driven system, it is. Joan Comeau photographed it and put the photos on Facebook but no alarm bells rang because of two things. One, it was a good photo, close and clear and without context. Two it was too close to give an impression of bulk and colouration. I saw it a couple of days later. It was on the ocean in a strong onshore wind and sitting in a glare patch with hundreds of other gulls. I could see the Mew in it but that was all as colour definition was not possible and my eyes declined to play under the conditions.
When Alix and Ronnie d’Entremont saw it a few days later, Ronnie had a more distant photo and clang went the alarm bells. When the photos attracted further comments on Facebook, clang, clang and I made plans to go back as soon as circumstance allowed, which was two days later.
Sandra and I went to Meteghan on March 14th and I saw the gull easily through the naked eye at 100m, which is odd as my eyes are almost always fully dressed by Swarovski when birding. In the excitement I wandered out onto the beach and began to make myself unobtrusive and unthreatening. Unfortunately, gulls that would normally take bread from your hands don’t go for this when on a beach and often fly, taking every other gull with them. The Kamchatka Gull was often the first up but I persevered, spending some time ill-dressed and stood in water, taking wing shots for they are one of the keys to confirmation. After a short break at the aforementioned Sip Café, we went back and I did it all over again. Now I’m going to start showing you photos of the birds, of Mew Gulls and of Common Gulls too, enjoy.
From our point of view, even though it is not as relevant as might be suggested, I’m starting with Mew Gull. There are big gulls and there are little gulls. Think of Great Black-backed through Herring Gulls as a 100% gull. Think of Bonaparte’s as a 25% gull, then Mew Gulls, Common Gulls and Kamchatka Gulls should all sit around the 50% mark. California and Lesser Black-backed would be 75% gulls if you were wondering. That gives you a sort of size baseline for the subject matter here.
The putative name for Mew Gull when split is Short-billed Gull but, it is only being called that in relation to Common Gull so why not stick with the distinctive Mew Gull?
These are all non-controversially Mew Gulls with an immature and then adults. Note how slim they look, how small featured and that bill, short or what?
This one is included to show the wing pattern. It is distinctive but we don’t need to debate it here too much.
You can see that there are structural similarities between all three 50% gulls, just as there are if you include Ring-billed in the mix, we won’t, but I’m just making the point that they are all from the same evolutionary divergence so will share similarities.
The ‘dove-like’ head of a Mew Gull shows well here, as does the concave nature of the shape from wing-tip to head. This feature is included in the excellent new paper on the complex that Alix mentions. I don’t want to get too technical so I won’t fully reference it.
This immature shows the nice, rounded head shape and gives an idea of proportion. It is a slight gull but still a 50% job.
Common Gull is just that, very common in most of northern Europe. I have seen tens of thousands, they don’t vary much in mantle colour and none come anywhere near to the mantle colour of the Kamchatka Gull, of which there will be many photos soon. I’m going to stick with adult Common Gulls and gratefully acknowledge the use of photographs taken by Darren Matthews (below), they help enormously to depict the species.
This one beautifully captures the flying bird. You can see that it is heavier than Mew Gull and the wing pattern differs. The mantle is also lighter.
Two Common Gulls nicely posing, showing their underwings.
This one is one of mine from Europe. Note the shape and the horizontal carriage, I’ll come back to that feature later.
Note the broken white eye ring here, it seems more obvious than that found on the Kamchatka Gull, better defined by the duskiness of the face.
This one is a Common Gull from Lower Sackville, NS. And, on structure, you could perhaps debate it but, the wing pattern is Common Gull and again note the horizontal carriage. Look also at the relative bill structure, colouration and markings.
Now here are the Kamchatka Gull shots, lots of them!
There two are in direct comparison to a Ring-billed Gull. Common Gull would be slightly darker than Ring-billed, the Kamchatka is as dark as the graellsii race of Lesser Black-backed Gull. Look also at the stance. The carriage is more angled back, the bird is more deep-chested than Mew and bull-necked.
These shots show the typical standing posture of the Kamchatka Gull. The last two show that the eye is not actually black but dark.
When the waves came along the posture altered slightly, presumably to keep dry.
The wing pattern is important and this sequence shows under and upper wings.
In flight the bird looks bulky, the body appears to hang beneath the wings giving it a hump-backed appearance.
The last few shots show the bird actively feeding rather than flying away. The distance was a bit greater, these are the more recent shots obtained after a 5+ hour search.
If you got to this point, copy IMAGLLNT into an email, send it to me and I’ll send you a certificate of endurance. I wouldn’t show it anybody though because it might confirm that you are nuts about gulls and you might not want that out there.
One sparrow does not a summer make, or something similar. Actually its spring and a Swallow (species unspecified) but who’s counting?
Following the screech-rattle and growl of the newly arriving Common Grackles, there has been a feeling of change around Cape Sable Island recently. The Atlantic Brant numbers are climbing steadily and areas around The Hawk are awash with them. The first few Fox Sparrows are also tricking in, or at least I presume they are new arrivals, they’ve been pretty scarce over the winter, there had been at least two, perhaps three commuting around CSI but only being seen irregularly. I had one in the yard 3/19 and two together, 3/20 so it is likely that they are new in, especially as others around Nova Scotia are finding them too.
Back in the UK, it used to be that, for me, four species denoted the start of spring migration; Chiffchaff, Blackcap, Northern Wheatear and Bank Swallow (Sand Martin). The lines for the first two are now rather blurred by increasing numbers wintering in the UK and Northern Europe, the latter two are of more interest to us in Nova Scotia (not that a Blackcap would be ignored, no siree!).
It is not surprising that Northern Wheatears don’t have the same harbinger of spring status in North America as they do in the UK, their migration route to Northern Canadian breeding grounds is somewhat more complicated and they are considerably rarer south of their breeding range, Bank Swallow however is a puzzler. Normally the first hirundine of spring here would be Tree Swallow, followed by Barn Swallow with Bank Swallow (and Cliff) lagging a bit behind. At exactly this time of year at inland sites in the UK, I’d expect to be seeing the first Bank Swallows, here odd ones might make it in April but early May is the more regular time, why?
Barn Swallows on both sides of the Atlantic seem to have largely similar breeding and wintering latitudes (see the map link below) and Nova Scotia is significantly further south than say my old patch at Colwick Park, Nottingham. I find the difference quite intriguing. No doubt mean temperature and food sources are the definitive reason although, given that the beach flies are on the wing even during periods of snow, a lack of food would not seem to be the whole issue, nor should the temperatures, at least in the southern part of Nova Scotia.
I would also speculate that, perhaps, the Bank Swallows that breed in the north (here) are the ones that winter the furthest south, performing a ‘leapfrog’ migration that is found in some other species and thereby taking the longest to complete their migration. I did do a web search and checked my own reference library but came up with nothing concrete, fascinating.
Out of interest, the average March temperature range in Nottingham, UK (my obvious point of reference) is 3°C to 9°C whereas in southern Nova Scotia (Tusket) the figure is -3°C to 6°C. Perhaps this is the primary issue that keeps Bank Swallows from arriving earlier, having said that, Maine has a warmer mean for March but still enjoys the same general arrival period as Nova Scotia.
While spring creeps in, no doubt to be curtailed slightly by a run of predicted nor’easters, winter continues to slip out the back door but leaving a smattering of Glaucous Gulls in its wake. While Meteghan has had a good selection of Glaucs recently, followed by a few at Lower West Pubnico this winter, CSI has not done so well for them. Odd ones have been seen but none have been too consistent. Bucking that trend slightly, I’ve seen the same second-cycle around Daniel’s Head on each of the last four visits. I got the shot below recently, it was c80m away so is not perfect but the new lens did an admirable job. On 3/20, there were two Glaucous Gulls at Daniel’s Head, both 2cy, but no Iceland Gulls, an interesting shift in species dynamics but for no discernable reason.
Speaking of Meteghan, I recently ‘got’ my Kamchatka Gull there, years after thinking that I’d had one in the UK (see previous post ‘Off Island, from Feb-4th). I then downgraded it, perhaps not the right term, to being a Russian Common Gull (poor name, Putin’s Gull perhaps?) but even that is open to speculation, either way it wasn’t ‘normal’. I’ll do a post about the Kamchatka Gull later, warning, it might make your brain seep gently out of your ears but each to their own I think.
Finally, a few more new lens exercise shots, just light jogs, I’ve not really taken it for a sprint yet.
Sat watching the rain running down the window panes, heavy blatter by the Rain Gods scale (see Hitchhikers Guide to the Galaxy triology, book four I think), I started to look through my shorebird photos from Nova Scotia, all taken in 2015. I do this from time to time so that I can make a mental note of what I’d like to have a better photo of, a mental note that I then lose along with shopping instructions and turning off the heater in the bathroom after a shower.
After perusal, I thought to stick them here, and why not, when those virtually unbirdable wet days come along we have to amuse ourselves somehow. Then, I thought, why not expand it to include all the shorebirds you’ve seen and photographed in North America, so I did and here it is. This post is obviously more for those who just like to enjoy photos and I know I don’t cater enough for that audience these, not everyone wants tertials, gonydeal expansion and cloca pecking.
Northern Lapwing – didn’t say they were all good photos!
Greater Yellowlegs – Lesser Yellowlegs. Two for one
So, there we are, lots of nice, well mostly nice photos. I might do gulls next!
After what has been a different week! Sandra and went out in the fine March sunshine to check a few spots and to try out the new lens in better conditions. There weren’t that many birds about, it is the switch-point where winter birds are slipping away before summer birds have packed their vacation bags.
In a post before the last, (the one about the hybrid calidris that you probably didn’t quite get to the end of, no more comments?) I revealed to the world that Sandra had bought me a nice, shiny new lens. For the technical minded it is the EF 100-400mm f/4.5-5.6L IS 11 USM and I’m rather liking it. Subject matter was scarce but it auto-focusses much faster than the old lens and the image is sharper with greater depth of field. I can’t wait to wave it at a vagrant warbler or sparrow.
This Turkey Vulture was not happy to pose and flew as soon as we pulled up. The rapid focus got some sort of a shot. The test of the focusing ability will be form a moving boat or as that distant South Polar Skua bombs past Baccaro in a rainstorm.
This Bald Eagle was some way off but the detail is pretty good. I find Bald Eagles hard to photograph, losing detail in the dark coloration, I much prefer photographing sparrows and warblers.
Parking lot gulls are ideal for photography practice. This Ring-billed Gull came up quite well. The head shots show a nice depth of field plus detail.
This Herring Gull is in breeding plumage although the bill will probably colour up a bit more.
This drake Greater Scaup was a nice subject to shoot a few shots of. It was about 35 feet away with the sun behind me. The vermiculation on the back are a particularly good test of the detail that the lens is capable of.
This Black-capped Chickadee was slightly back-lit and so the eye gets lost in the black plumage a bit and it slightly washed out. I need to work on how to counter this problem and perhaps try a bit more post-shooting manipulation to get a more pleasing result.
So I can pronounce myself happy with the lens so far. My shutter release finger is itching to try it on a few more colorful subjects, bring it on spring!
While birding on Cape Sable, CSI on Sept-16th 2015, Ronnie d’Entremont and I were photographing shorebirds when I saw a very rusty looking Dunlin (Calidris alpina) type. The bird was amongst a mix of roosting Semipalmated (Calidris pusilla) and Least Sandpipers (Calidris minutilla), nearby were several White-rumped Sandpipers (Calidris fuscicollis). The Dunlin was in a plumage unfamiliar to me and I thought it perhaps a juvenile, based on a quick reference to the Sibley app at the time, a Dunlin plumage rarely seen away from the breeding grounds, apparently.
A few photos of the bird were taken, but they were just part of a larger batch of shorebirds and not critically re-examined during processing. After posting the photos on my blog, Ontario birder Alan Wormington left a comment suggesting that the bird was in fact likely to be a hybrid between Dunlin and White-rumped Sandpiper. You will see from the reference list that Alan has experience of this hybrid combination.
I immediately looked at the photos again but with a more critical eye. It was clear that the bird was in worn plumage with noticeable bleaching of the coverts and some worn scapulars, not something that should be associated with a juvenile Dunlin and more indicative of our bird being an adult. A web trawl revealed further instances of presumed hybridisation between Dunlin and White-rumped Sandpiper and so I thought it worth writing up the Cape Sable bird and inviting comments.
Hybridisation amongst calidrids
There is some recorded history of calidrid hybridisation. During research I made reference to three mainstream sources: The Shorebird Guide, O’Brien M, Crossley R and Karlson K. (Houghton Mifflin, 2006); Shorebirds of North America, The Photographic Guide, Paulson D. (Princeton, 2005); Shorebirds of North America, Europe and Asia, a Photographic Guide, Chandler R. (Princeton, 2009).
I also read the available notes on Dunlin x White-rumped Sandpipers as listed in the references at the end.
Dunlin as a starting point
Dunlin is a familiar shorebird to birders in North America and our subspecies in eastern North America is C. a.hudsonia. The presence of C. a. arctica might also be expected to occur in the east although it would be classed as a rare vagrant. In the west, the subspecies C. a. pacifica is to be expected and is suggested to be sufficiently morphologically different as to be readily identifiable in the field. In Nova Scotia, Dunlin are scarce in spring but common as a migrant in autumn and, around Cape Sable Island at least, some winter in small numbers in most years (McLaren, 2011).
Breeding ranges of Dunlin races
Calidris a. arctica, northeast Greenland.
C. a. schinzii, southeast Greenland, Iceland, the British Isles, Scandinavia & the Baltic.
C. a. alpina, northern Europe and northwest Siberia.
C. a. centralis, north-central and northeast Siberia.
C. a. sakhalina, eastern Russia to the Chukchi Peninsula.
C. a. kistchinski, around the Sea of Okhotsk to Kuril Islands and Kamchatka.
C. a. actites, breeds on Sakhalin.
C. a. arcticola, breeds from northwest Alaska to northwest Canada.
C. a. pacifica, breeds in western and southern Alaska.
C. a. hudsonia, breeds in central Canada.
Below is a map showing the distribution in N. America of Dunlin, followed by a map of the breeding range of White-rumped Sandpiper, both maps reproduced with the kind permission of Terry Sohl.
One of the Dunlin races, C. a. hudsonia, shares a breeding range with White-rumped Sandpiper, both species occupying the same wet tundra habitat and therefore presumably competing at some level for the same summer territories.
Dunlin of the subspecies C. a. hudsonia/pacifica in juvenile plumage are illustrated in field guides as very rusty in appearance and are described in Chandler as having a ‘rather rufous-toned head and breast with a brownish crown. Upperparts darkish brown with rusty-fringes, often with a pale mantle-V; breast and belly strongly streaked or spotted, remainder of underparts white’. He adds that only the European races migrate south in juvenile plumage, ours and other races have a body moult on or near their breeding grounds.
This information is generally reproduced across field guides and accords with my thinking that our rusty bird was in a juvenile plumage. In the field, had I paid critical attention to the coverts and noticed that wear there would not be a feature of a juvenile, I might have concentrated more on getting better photo documentation, including waiting for wing flexing and trying to better document back and rump pattern.
To establish a Dunlin baseline image, here are a selection of photos, some from the same period and location:
This adult (possibly 1st summer) Dunlin taken September-1st is in moult but still retains the black belly and many abraded feathers of summer plumage. Once the moult is complete it will look like this:
Here is another example of Dunlin in winter plumage, taken October-31st elsewhere.
The image below is of a moulting adult Dunlin, take on the same day that the hybrid was observed:
The pictorial reference below, taken on Cape Sable on September-1st 2015 shows another Dunlin, this one is a typical juvenile. Note the pale edged scapulars in moult to winter grey; pale edged juvenile scapulars are a typical trait shared by many juvenile shorebirds. A month later this bird should look quite different.
Having established what a Dunlin looks like in adult summer, winter and late-juvenile plumage, here is the putative hybrid. Of the images taken, these are the best. You can see straight away that the coverts are adult and in moult. The scapulars are still clean and fairly fresh looking. They have elements of White-rumped Sandpiper about their shape but also, and I’m not seriously suggesting an alternative candidate, of breeding Rock Sandpiper.
The overall impression of the bird is Dunlin-esc, but it lacks the sad expression. The breast, belly (as much as can be seen) and the flank markings are very well-defined. The overall colouration is too rufous, the bill is possibly too short and seems overly robust for Dunlin. The supercilium would appear to be too well-defined for Dunlin, more akin to that of an adult White-rumped Sandpiper in breeding plumage, and this is perhaps one of the major clues regarding parentage.
This second image of the putative Dunlin x White-rumped Sandpiper hybrid offers a slightly more angled view and reiterates the points already made especially the supercilium and general head pattern. The belly and flank barring is also better illustrated offering a further, strong indicator of lineage. Divining the parentage of any hybrid is a case of looking for clues that fit one or both of the suppliers of genetic material. That there are similarities to Dunlin is unquestionable but what about White-rumped Sandpiper traits?
Below is a shot of a White-rumped Sandpiper from the same location and date. This is a moulting adult, as shown by the wear to the wing coverts and vestiges of summer plumage. It might be regarded as lightly marked but the head structure, if not colouration, is interesting.
Below is a further image of another adult White-rumped Sandpiper at the same location (front bird), taken on September-1st 2015. This bird shows better defined flank markings than the previous bird, it also shows similarities with the putative hybrid calidris.
Below is another moulting adult White-rumped Sandpiper, taken in Quebec, September-5th 2009. This bird shows a different posture again, having the attenuated look we expect of White-rumped Sandpiper.
The image that really confirms the hybrid’s lineage is found in The Shorebird Guide, page 163, plate 6. This bird could almost be our hybrid except for the bill (too short) and perhaps the primary projection. The next best is the sleeping bird below (centre). Many thanks to Rick Whitman for his permission to reproduce the photo here.
More visual reference
Below is a sequence of head shots of Dunlin, including the Cape Sable putative hybrid (bottom bird) and a White-rumped Sandpiper, (middle right). The bird believed to be C. a. pacifica is centre. Note the very different facial expression of pacifica, do winter birds have the same features? If so, that feature alone would allow relatively easy field separation.
The following three images are all of C. a. schinzii and are included here to give a further example of Dunlin plumage and structure variation. There are aspects of schinzii head structure and plumage that compare favourably with the hybrid’s and, while unlikely based on range, there is no conclusive reason not to consider that schinzii may be involved. I am greatly indebted to my friend Iain H. Leach for permission to use the images, see more at his web site at: http://www.iainleachphotography.com/
Although the photo of the hybrid is limited in that certain aspects of the bird cannot be seen clearly, the essence of the individual is Dunlin, race uncertain, however, the following features are wrong for Dunlin:
The bill is rather deep based, similar structurally to White-rumped Sandpiper.
The overall colour is too extensive on the head for Dunlin but very similar to a June (breeding plumage) White-rumped Sandpiper.
The supercilium is too extensive for Dunlin, again recalling White-rumped Sandpiper in the full flush of summer plumage.
The eye is in the wrong place and the head shape not oval as in Dunlin.
The breast/flank markings are rather bold and extensive, they match a spring adult White-rumped Sandpiper.
To my eyes, the hybrid lacks the ‘sad’ expression of a Dunlin.
The scapular pattern is more suggestive of White-rumped Sandpiper than Dunlin.
The closed wing appears to project beyond the tail more than it would on Dunlin, but less than it would on White-rumped Sandpiper.
The evidence, in my opinion, indicates that this bird is a hybrid showing predominantly Dunlin structure but White-rumped Sandpiper in plumage.
That two distinct species break the biological rules and create hybrids is both interesting and confusing, not least when you are presented with an example in the field. Thankfully, we can rely on our digital friends to furnish us with the requisite images which we can then forensically dissect. If hybridisation is more widespread than we understand, will it be more readily found thanks to digital photography? Have we got our own, eastern North American, Cox’s Sandpiper?
And finally, just to continue on a hybrid shorebird theme, a sort through my own Dunlin reference photos included this doc-shot of an individual at Baie du Febvre, Quebec, in September 2013. It was present while a Sharp-tailed Sandpiper enthralled us and so got completely ignored. To me this bird has the characteristics of a Pectoral Sandpiper x White-rumped Sandpiper although that bill is very straight. Comments are welcome.