Tuesday, November 25, 2008

It feels like Iceland too

I spent about 45 minutes in NW gales at Tiscornia this morning.  When a common loon crash-landed amidst the gull flock (setting them all to flight) I should have known that there wasn't going to be much movement.  It was actually banded green over silver on the left leg and soon flopped back into the surf.  It was really too windy to get much use out of the scope and I headed south.

After not seeing a whole lot at the landfill (though there were loads of gulls), I headed on to 3 Oaks where Tim found a California gull yesterday (for an interesting challenge click on Tim's bird pics under Michigan links and age the bird, it's not a common one).  Today there were glaucous gulls and a lesser black-backed as well as this quite white-headed bird:

I first picked it up facing straight towards me and it stood out as its head was virtually unstreaked, contrasting from the herring gulls.  With closer study you could note pinker legs, a dainty bill and a slightly darker (but still yellow) eye than the Herrings.  The eye might briefly make a person think Thayer's, but they are more heavily hooded than a Herring generally.  I waited for it to turn broadside to see how much gray it would show (Kumlien's Iceland gulls are quite variable in this regard), and it eventually revealed neat charcoal patterning to the leading edge of the wing fading to white on the trailing edge.

Here's a comparison of another Kumlien's Iceland gull from February 07 which showed more extensive, and blacker, wingtips than today's bird.  Today was the earliest I've ever had an Iceland gull.

Saturday, November 22, 2008

A tribute to the Buckeyes

As we speak Ohio State is finishing up a beat-down of historic proportions on one of my alma maters, Michigan which I guess I will acknowledge with the above photo.  I don't think I would have named my school after a butterfly, but if it works for you OSU-fan, so be it.    The pic is from some time last fall when Tim and I were trying to kick up sharp-tails. 

Earlier in the week I took this pic of a winter plumaged horned grebe in the St Joseph harbor.  I'm finishing a string of night shifts tonight so hopefully will be able to do some actual birding this upcoming week if Thanksgiving preparations and November blizzards would stop interfering...

Thursday, November 13, 2008

1000 miles

Today I hit one of my goals for my Bigby year and somewhere along the way to Tiscornia beach this morning biked mile #1000.  A flyby juvie glaucous gull put me at 227 (other recent additions are cackling goose yesterday close to home - unfortunately found during 45 degree rain so no pics and faithful readers are spared another goose post, and a few purple finches about the yard).  I had somewhat hoped to get to 1200 miles, averaging 100 miles per month, but given that bicycling during the winter months here is dangerous, if not impossible, I don't think that's a goal I'm going to push for.  At this point my goal is to reach 230 which I may be able to accomplish with just 2 (or maybe 3) more rides.  Lesser black-backed gull should start roosting on Lake Chapin in a few weeks (I should probably check that it's not already there) which is about a 20 mile round trip.  Long-tailed duck and Lapland longspur should be at Tiscornia on any given December north winds day.  There's also the chance that I could run into a snow goose or shrike close to home and duck back out after them (that's what happened with the cacklers, and I attempted it with a golden eagle less than a mile from the house that crossed the road and perched in a snag as I drove home a week or so ago, but that had flown by the time I returned 10 minutes later on the bike).  I could also theoretically get motivated to go for long-eared owl should one be teed up in the Sarett pines, but at 30 miles round trip, I don't know if that will happen.  I actually toyed with the idea of trying the 65 mile trip for Franklin's gull down at 3 Oaks, but if there's one thing I've learned chasing birds, it's that gulls are not reliably re-found.  Fortunately I slept through the 4:30 am alarm I'd set this morning.

Today's pics are from the berry trees in the cul-de-sac in front of the house.  Waxwings and robins were swarming, but not being very cooperative about holding still:

Friday, November 7, 2008

Black skimmers

Today I continued my ongoing efforts in multiple states through multiple times of year to dig up any variety of saltmarsh sparrow. I added Back Bay NWR to that list of places where I couldn't find a sharp-tailed or seaside sparrow. I pished up swampies, marsh wrens, got rises from sora and (appropriately) Virginia rail, but found no candidate ammodramids.

Today's pics were taken yesterday and show some moult in black skimmers. I assume that this first bird is a bird that has nearly completed the moult out of juvie plumage and into adult winter:

This is an adult in the process of moulting into winter plumage, you can see there are still retained brownish-black feathers in the wings. The bird is only starting to form the white nape that's the hallmark of winter plumage.

This bird is still in breeding plumage with a completely black nape. I'm a little surprised that it has glossy black feathers with the fully black nape since the previous bird moulting out of breeding plumage had a lot of faded feathers in the wing. In the field my assumption was that it had completed the moult, not realizing that winter birds have white napes. I think this is a female, I also didn't realize until I later cracked open Sibley, that females are smaller with less hefty bills. I remembered seeing one smaller all black-backed bird in the group, I think this is it. Perhaps there's some difference in the sexes in the moult timing or maybe differences in how fast the feathers wear depending on parental duties.

random final Virginia Beach thoughts and pics

Here's Hazelnut at the Virginia Zoo with what I assume is a black swan. Unlike most of the zoo's denizens, this one did not qualify as "big and strong."

Cormorants in front of the sunrise:

This photo is dedicated to the stalwart souls/freakshows at Whitefish who keep track of the puny little freighters that pass through the straights. This, I believe, is the USS Eisenhower (based on the 69 on the bridge), a Nimitz-class aircraft carrier. Another 20% or so of the ship's stern extends out of the photo. I tried to get flight pics of the F/A-18's that were flying around (as well as some F-16's - though I didn't think F-16's were based on carriers), but the flat gray coloration just makes them disappear immediately into the blue sky if you take your eyes off them for a second to try to line up the scope. I'm told the Virginia Beach/Norfolk area has the greatest concentration of naval bases anywhere, or something like that. Some days there was a constant din of fighter jets on exercises (mostly the crappy weather/misty/foggy days). Apparently a lot of the beaches around here are owned by the military without public access or significant development.

Finally a view of a habitat you don't often see in Berrien, a cyprus swamp from First Landings State Park. It inspired me to bang out some double-knocks on the boardwalk. A bird quickly flew by and I heard a loud "kent" call. While I did see a blue jay about, I took the experience as undeniable proof of the continued existence of ivory-billeds. Oh and the cormorant sunrise photo obviously has first state record red-faced, pelagic, and Brandt's cormorants in with the flock.

the holy graelsii

Like I said last post, it's not a birding trip ... but I did get out for 2 hours this morning to First Landings State Park to (successfully) look for my lifer brown-headed nuthatch. And though it's not a birding trip, I did manage about 60 images on the beach during naptime (hooray nappytime). I focused mainly on the lesser black-backed gulls (L. fuscus graelsii) since we don't get them in great numbers in Michigan, finding multiple individuals of most of the age groups.

First is a juvie. Both of the first two pics are of the same bird. In the lighting of the first pic it has the cold dark brown typical of the plumage, in the low evening sun of the second it takes on more Herring gull warmer medium tones. ID points include the very long primaries (which I cut off on the first pic), the very neatly marked wings (especially of the greater coverts), and the cold dark gray tertials with narrow white edging:

I'm not entirely sure of the age of this bird. I think it's acquiring 2nd winter plumage given the (scant) gray coming into the back and scapulars, but it still has the juvie pattern (though very faded and blurred) of the coverts. I think (though I don't have the literature with me to be for sure) that this species probably moults its wing coverts as it acquires 2nd summer plumage as the 2nd winter typically has solidly medium brown wing coverts. I think this bird probably skipped that step. The tertials have the charcoal gray feathers with bright white marbling at the edge typical of 2nd winter plumage for lesser black-backed's though:

Here's a more typical individual acquiring 2nd winter plumage with charcoal gray feathers making their way into the mantle and coverts. Its eye is lightening (the previous bird's was dark). It too sports the brightly marbled tertial edges:

Moving along, we have the 3rd winter bird. It has nearly acquired the adult look to the back and wings, has a bright eye, but has the very dirty bill typical of this age group in this species. This one's legs are still fleshy-pink. Note this bird is also moulting its primaries and so appears short-winged:

Finally we come to the adult winter type birds. They have a quite variable amount of head streaking. Both of these 2 are middle of the road. The first bird's primaries are probably missing at least 2 feathers as they're very short:

I think lesser black-backed is probably my favorite gull of the medium and dark backed group (it'd probably be Iceland amongst the whitewings and Little for the hooded group (though I reserve the right to change those picks should I ever see an ivory or Sabine's gull. Not sure where Ross's would fit in...)

Thursday, November 6, 2008

They don't look like they're laughing to me...

We're in Virginia Beach to visit my in-laws who just had a beautiful little (red-headed!) baby. And while this isn't a birding trip, I did bring along the scope, camera, bins (oh and hip waders, hopefully more on that tomorrow or the next day).

After driving through the night there wasn't time for much other than some visiting in the morning, an afternoon nap, and more visiting in the evening, but I did hit the gull flock behind the hotel (there were also brown pelicans and gannets well out).

Predictably laughing gulls were well-represented, showing all of the plumage types for this time of year, first off a first winter bird with a fresh gray mantle and retained (worn) juvie wing feathers:

I haven't entirely made up my mind on the ages of some of these birds (it's hard without bill, eye, or primary color differences that can make it easier in the big white-headed species). The two with their heads in their mantles are first winters, I'm not certain if the dark lead bird in the foreground is an advanced first winter, or more likely a 2nd winter that's still in the process of moulting the wing feathers:

Here's a similar bird on the left (also probably a bird attaining 2nd winter plumage) with a bird that's pretty much full 2nd winter on the right:

Finally we have the adult winter-type birds:
There were also good numbers of both black-backed gulls though relatively few herring gulls, hopefully I can manage some decent ranges of them as well. Tomorrow I'm hoping to try to track down brown-headed nuthatch and depending on how much time that takes, may try to hunt for sharp-tailed and seaside sparrows with the waders if I can find some habitat. (Are there alligators in Virginia???)

Tuesday, November 4, 2008

I vote for parvipes

I've been putting a lot of thought (yeah, yeah, entirely too much) into these ridiculous small geese.  I had hoped today to find a snowy owl that's been reported close to home, though is not pinned down to any one location over about a 8-10 square mile area it's been reported from.  I didn't find the owl.  What I did find was more small geese!  Clearly the fates were with me in that they're from the group that has been causing me problems: small plain birds the same color as Canadas without bright scapular edging.

I spent a lot of time in the last blog discussing whether small runty interior Canada geese (the common migratory form in Michigan) could be part of the cause for confusion.  The small birds, however, are all about the same size.  Unless dwarf geese are common in that subspecies for some genetic reason, if the small birds are small because of poor habitat where they're fledged, then there should be a range of sizes which there isn't.  Though I maintain that the support that David Sibley gives based on his interpretation of the data for runty interiors being unlikely to cause confusion with hutchinsii  Cacklers isn't entirely valid, it seems unlikely that he would write something that doesn't jive with his experience (which obviously is quite valid).  Therefore, if these birds aren't all small interior Canadas, and they aren't hutchinsii Cacklers that means they're something else.

The Michigan Bird Records Committee 2005 report (viewable here) discusses the specimen record in Michigan.  The University of Michigan Museum of Zoology has specimens of several hutchinsii Cacklers ... and one "assigned to the subspecies taveneri."  Tavener's Cackling Goose is a bird of the Arctic coast of Alaska and winters in the Northwestern U.S.  It is also the subspecies of cackling goose closest to the parvipes Lesser Canada goose, and some authorities apparently consider them difficult, if not impossible to separate.  I think this would lead me to suspect that a 4th white-cheeked goose occurs in Michigan, the parvipes Lesser Canada Goose.

I did some google searches and came up with a couple of enlightening webpages from birders in the western U.S. in the expected wintering range of parvipes Lesser Canadas.  This excellent one from Denny Granstrand in Washington has nice photos of most of the Cackling goose subspecies as well as the western Canada goose subspecies with notes on ID.  Harry Krueger's from Idaho further details ID of parvipes Canadas and hutchinsii Cacklers.  The biggest general difference they describe is that hutchinsii Cacklers have very square heads with very vertical foreheads (think more like a Barrow's Goldeneye) whereas parvipes Canadas have rounder heads whose foreheads slope more evenly into the bill (think more like a canvasback).  If you pull out your big Sibley, you'll find this illustrated as well (although again not field marked).

Here's my two geese from today.  You see a forehead that slopes into the bill (admittedly somewhat accentuated by the positioning):

The next 2 photographs show 2 things, first the effect that the birds in the background of a digi-scoped (or any shot taken with a big lens) will appear relatively larger.  The small goose in the first photo is not dwarfed by the nearby presumed interior like it is in the second.  To me the patterning in the scapulars seems to change somewhat with the lighting, appearing slightly more prominent in the sidelit sun but slightly less prominent in the shade:

Finally another view of the scapulars in direct sun showing little edging to them (note that the interior it's with has a weak white crescent at the base of the neck, something they don't often show - though don't make that mark a priority of study in the field if you have limited time to view an individual, almost everyone agrees it's a variable feature in all populations)
The bottom line, is that I think that parvipes lesser Canada occurs in Michigan, and accounts for a lot of the small brown white-cheeked geese seen in late October and early November.  It seems that the shape of the forehead provides a lot of the sense of a bill's relative "stubbiness," so add vertical forehead for cacklers to the vertical bill base for Ross's goose for things to study in small geese.

Saturday, November 1, 2008

What's a cackling goose?

I think I'm as confused as I've ever been, and have come to the conclusion that I have no idea where to draw the line in the sand between Cackling and some Canada geese.  

The wonderfully mud-clear nomenclature is ironically representative of the problem.  "Cackling goose" used to refer to a subspecies of Canada goose found in coastal Alaska, a small very dark bird that formerly went by the trinomial Branta canadensis minima.  The form of small goose that migrates through Michigan, the "Richardson's goose," went by the trinomial of Branta canadensis hutchinsii (nice that the bird is named after 2 different people).  Now several of the small subspecies of white-cheeked geese are lumped as Cackling Goose with the scientific name Branta hutchinsii - a full species now goes by the former common name of one of the subspecific forms and the former scientific name of a different subspecific form (and includes a couple others as well).

In Michigan 3 forms of white-cheeked geese occur (to my knowledge):  the non-migratory and introduced "Giant" Canada (maxima subspecies), the migratory "Interior" Canada (interior subspecies), and the "Richardson's" Cackling (hutchinsii subspecies).  A problem comes in that runty "Interior" Canadas are known to occur.  Size is a good screening test to look for candidate cacklers, but is not all a person can go on.  A proportionately small bill is said to be strong support for cackling, but there are other plumage differences (grayer plumage, especially of the breast, in "Richardson's" hutchinsii Cackling as compared to Canada, with more brightly edged scapulars in the "Richardson's" as well).  The scapular edging brightness is shown in the illustration (though not "fieldmarked") in the big Sibley, but is explicitly described in Sibley's web article as a good mark for "Richardsons" Cacklers.

I started my dilemma with some birds recently photographed in Ann Arbor; photos by Laurent Fournier can be viewed here.  There's a large Canada, and 2 smaller white-cheeked geese, one obviously a size bigger than the smallest, but still much smaller than the largest.  To my eyes there are small plumage differences between the smaller birds and the Canada:  their breasts are slightly grayer and there is the suggestion of a white collar at the base of the neck.  To my eyes there is no difference in the edging of the scapulars.  I have always called birds like these runty Canadas.  Contrast those birds with another small Ann Arbor goose viewable through the umichbirders Grovestreet.com web album here photographed by Lyle Hamilton at Avis farms. This bird has quite brightly edged scapulars and an even more prominent collar at the base of the neck, though appears very similar in tone and color to the surrounding Canadas in similar postures.

 This is a bird I photographed on Ford Lake in Ann Arbor in mid-March a few years ago.  I labeled it a runty Canada.  It follows the pattern of the first photo, a smaller bird with a slightly browner breast, but scapulars essentially identical to the surrounding large Canadas.  It does have a collar at the base of the neck, unlike most Canadas.  It was slightly larger than an even smaller bird that was also present that I labeled a cackler (though that I didn't manage great photos of).  The bill is smaller than those of the surrounding birds, but is it small enough?

This is a very similar bird I photographed at the LMC ponds here in Berrien Co in mid-October 2 years ago.  Again, a bird with a brown-gray breast making a whitish collar visible at the base of the neck, a small though not stubby bill, and the same brown color of the back with little edging of the scapulars:

Compare that with these birds in similar lighting from last October, small geese that are much grayer overall with brightly edged scapulars, birds that I'm confident are cackling geese.

The final 2 pics are also from the LMC ponds from last December of 2 cackling geese that show all the differences, small size, short bills, grayer plumage, and brightly edged scapulars (note that the lead bird is more brightly edged than the trail bird)

So what to do with the small brown birds that lack the bright scapular edging?  I think that Lyle's Avis Farms photograph of a Cackler does show that not all Cackling geese in all lighting conditions are as silvery-gray as easier ones.  I don't know, however, that it convinces me that all the brown birds without bright scapular edgings are Cacklers.  

Sibley spends a good amount of time in his web article discussing bill size, going so far as to say, "Actual and proportional bill length may be the single most useful feature to study when trying to identify Canada and Cackling Geese."  He reviews data from a paper and book which I don't have access to (so can't fully analyze the original data).  However, interesting graphs are shown, demonstrating average bill size (including the standard deviation, a measure of how variable a sampled population is).  The general trend is that small birds have small bills and large birds have large bills.  Most of the subspecies groups have a standard deviation of about 5% or so, meaning an average bill size of 50mm long would vary between about 47 and about 53 mm in most birds.  However, there are 3 groups that have virtually no standard deviation (variability) amongst the sampled population: female moffiti Cacklers from the interior West, and male and female hutchinsii Cacklers.  In all groups except the moffiti Cacklers, the sampled males and females show about the same standard deviation (variability) in bill size.  It doesn't make sense then, that in a single subspecies of white-cheeked goose that there is a difference in the variability of the male bill and the female bill.  Therefore, I think we can conclude that the sample size was relatively small and that the females of that group likely do have the same variability as all other forms of white-cheeked geese.  Extending this out, it would also seem to make sense that hutchinsii Cacklers also have some variability in bill size as well.  The significance is that our migratory interior Canada geese were measured as having a bill size of about 51mm with a standard deviation of about 4mm.  That means (based on the standard deviation calculation and assuming a "normal distribution" of the data) about 2/3 of the interior Canada geese will have a bill size between 47 and 55mm.  A hutchinsii Cackling goose would seem to average a bill length of about 38mm with 2/3 having a bill size between 36 and 41mm.  How obvious in the field, therefore, is the difference between a large Cackler at 41mm and a small interior Canada at 47mm.  Even if you can easily see a 6mm difference in the field present between average birds, what of the runty Canadas that are know to occur???  An interior Canada 2 standard deviations from the mean (again assuming a "normal distribution") would have a bill length of 44mm and would comprise about 2% of females (or 1 out of 100 birds in a flock).  Now we're down to a 3mm difference.  

A critical reader (if there's any readers left at this point) could correctly point out that all those numbers do depend on whether white-cheeked goose bills vary on a "normal distribution".  Honestly, I don't know that it really matters.  What matters is that we know that runty Canada geese occur (as well documented by Julie Craves' classic online article).  They can be small birds and, at least in her photos, have a small bill as well.  It would be easy to say that those birds could fall 2 standard deviations from the mean, even if there aren't correspondingly huge-billed birds to make the data distribution truly "normal."  

Sibley, however, interprets the data differently.  In his Figure 1 on the far right side of the table is a comparison between captive-raised interior Canada geese on Akamiski Island and wild interior Canada geese on Akamiski Island.  He observes that captive raised birds are only slightly larger than the wild birds.  HOWEVER, that the paper's comparison is actually between captive-raised birds and average Akamiski birds can also be seen (the bill length of the comparison wild interior Akamiski birds are the same size as the other interior birds in the table).  The paper doesn't therefore appear to give us data on runty interior birds and so does not allow us to conclude that a runty interior Canada goose's bill would be only slightly smaller than a typical interior's.  (Of course it would help to have the actual paper to know that for sure ... perhaps I'll be writing a retraction...).

If, however, a person takes Sibley at his word that, "There is no evidence that the "runt" birds from Akimiski Island take on the short-billed proportions of smaller subspecies, and therefore should not cause confusion with Cackling Goose," then most, if not all, the birds discussed here are cackling geese... ... unless some of the borderline birds are parvipes Canada geese, the smallest Canada goose subspecies, that's much closer in size to hutchinsii Cackling geese than are the larger interiors.  Different range maps show parvipes as either slightly west of hutchinsii Cacklers or actually overlapping them somewhat, so it is conceivable that they could occur in Michigan as well.

At any rate, I haven't decided what to do with the small plain-looking birds.  I'm not convinced that I can truly say whether a bird's bill is stubby enough to be a Cackler's even if it's shorter than most of the Canada's that it's around.  One other potential issue is that most of the birds with nice brightly-edged scapulars are from November and December, most of the plainer birds are from earlier in the year.  I don't know if this implies again a different population of birds, or if possibly moult differences could be involved (though I would think that migrating waterfowl would be migrating with moult pretty much completed).  I think for me the scapulars are the best way to rule in a Cackler but can't decide if lack of bright edges rules them out (which I've typically done in the past).  At any rate, it's 4am and I think I'm finally tired enough to sleep...