Sunday, January 24, 2010

The hunted

I ended last year with 296 birds on my Berrien Life list putting me almost certainly on pace to hit 300 this year, at least a year earlier than I had expected after the impressive number of rarities which turned up last year.

Here's Number 1 on the list: ruffed grouse This is the first bird pic I ever took with the current camera I use, a bird that appeared under the feeders of my childhood home in Midland Co Christmas morning sometime early last decade. Per the current Berrien checklist it's the only "regularly occuring" species I'm missing, though is a rare breeder. "Regular" birds are defined as being seen in 9 out of 10 years (1995-2005). As I look back in the Field Notes, though, I see it was missed in 2005 and 2007, so the next time Jon revises the checklist, the grouse is going to get bumped out of regular...

Next are the "casual appearing" holes in the list, this being defined as 4 or more records, again, in the 10 year period of 1995-2005. There's 36 species in that category of which I've seen 29.

Missing are (in semi-phylogenetic order):

White pelican (photo from Ding Darling in Sanibel Fl) It feels like these get stealthed through the newspaper by a fisherman in the rivermouth every May, unreported until too late on the listserv. Looking back at the Field Notes, it looks like 3 Apr records and 2 from May in the last decade, usually from one of the big inland lakes (Chapin or less commonly Paw Paw).

Snowy egret (one of at least 2 I saw in Washtenaw)
I count 4 records in the last decade, 3 from May and one from April, clearly this bird will probably teeter between casual and accidental depending on what 10 year span you choose. None of the records have been while I've lived in the county.

Upland Sandpiper (photo from Muskegon - I saw 2 in Allegan that day too)
I looked hard for one of these last April in the South County without success. As I look back through the Field Notes, I see one from April, one from May, 3 from July, 1 or 2 from August, and one record from September. Clearly I need to move my target period. I wonder if the birds overfly us on the last legs of their migration northward whereas on the southbound migration they're just getting started and probably not going that far.
Western Kingbird is one of my state bugaboos, this one's probably from Colorado.
I see 3 records in the last 10 years or so, 2 from May and one from August, so this is another one that walks the line between casual and accidental. If memory serves me, Kip still needs Western Kingbird too.

Yellow-headed Blackbird (a crappy photo from Pte Mouillee):
This bird has had an odd distribution in the county with 5 records in 2003, 5 records in 2005, and I think 2 or maybe 3 in the rest of the decade. May is the most common month.

The other 2 birds currently listed as casual that I need are Sabine's Gull (would be a lifer) and Goshawk (which is quite get-able if a person can hit the hawkwatch dune with a good SE wind in March or NE wind in late October/early November).
There's a few others that are currently rated accidental on the checklist but will probably get down-graded to casual with the next revision that I need. This group would likely include Trumpeter Swan and Little Blue Heron (Lil Blue along with Black-backed Woodpecker are probably the "easiest" Michigan birds missing from my state list).

I'm going to try to apply myself to find the grouse drumming next month on sunny February days and add it to my owling nights as well. Hopefully my schedule will permit me to hit the dunes on the right day for a goshawk. As for what 300 will be, we shall see...

Thursday, January 21, 2010

Putting in the time

One of my goals every year is to get to Tiscornia 100 times, a number I've never come close to reaching sadly. My spreadsheets suggest that I find a review bird there every 40 visits or so, though obviously during the fall months with a lot of bird turnover (and the concentrating effect of the lakeshore's angle) that number is more favorable. In winter the odds are considerably less favorable, but I try to make token visits to try to stay on pace (maybe a more concerted effort would net a king eider, Barrow's goldeneye, or ivory gull after a decade or so). The last few times I've been there, presumably the same female-type Black Scoter has been in with the Greater Scaup flock, the same female-type Lesser Scaup has been in with a few goldeneye, and the same 2 Horned Grebes have been in the channel.

Today the winds changed and pushed much of the ice farther out into the lake and more birds were present. The greater scaup flock had about doubled and the scoters had changed. I walked out the south pier hoping for good photo light, but by the time I got to the end the sun was lost for good behind the clouds.
There's a couple adult males with bright white sides, but most are first-winter male Greater Scaup, a plumage aspect that Sibley doesn't illustrate though that is attempted in the Nat'l Geo. These birds are undergoing what Pyle terms the pre-formative moult which runs from about September through March. This moult, present in some species of birds, replaces hastily grown juvenile feathers and frequently transitions birds into a more adult-like appearance. It only occurs in first fall/winter birds. Most of the birds have managed medium gray backs though still with some dark retained juvenile scapulars along the rear edge of the back. The white side panels are still blotched with darker juvenile feathers as well.

The male in the foreground here, though, is a bit behind with a mainly brown side panel and only a narrow line of gray scapulars starting to come through.
Did you notice the Lesser Scaup in the rear of this cluster?

Here's the Lesser cropped more tightly from the above photos
Note the coarser vermiculations of the back, the difference in crown peak placement, the thinner head, and more restricted black at the tip of the bill.

Finally poor shots of some of the other divers that have been around (I really could have used the sunlight).

Monday, January 11, 2010

"arbitrary standards"

that are now up to me! (insert evil mwa-ha-ha-ha laugh here).

With the turn of the year, Ross's Goose has completed its 3 year "probation period," maintaining regular occurance in the state and is now off the review list, transferring the headaches of what is and isn't a Ross's goose from the committee to the NAB and MBNH compilers.

Here's a review of my experiences with Ross's-type birds in Michigan.

First the "best" Ross's I've seen, a bird I found in Washtenaw in November of 2002 or so. It has a vertical bill base and the most blue wartiness to the bill of any I've encountered. It was accepted by a 6-1 vote.

Next are 3 birds from Paw Paw Lake in March of 2006. The first pic shows what I took to be the female of the pair, the smaller of the 2 adults. It has a little more black along the tomia, what I would term a vertical or irregularly vertical bill base and some blue to the bill base.

Next the slightly larger of the adults, I assume the male, whose bill is not quite as vertical.

The first winter/first spring bird (with a little duskiness to the lore and some duskiness in the wing not visible in this pic) does have a more convex outward bill base, though I believe this is more allowable in first year birds (though I haven't yet come by a couple papers that apparently discuss this based on their title)...

These birds were accepted 7-0, 7-0, and 6-1 (my assumption is that the 6-1 bird was the "male" though that's purely a guess - though if the assumption that this was a family group is correct then it's not possible for only one to have been a hybrid).

Now we move onto even shakier footing.

I submitted this bird from March of 09 as a Ross's. It went to a 2nd round of voting with the committee, based on the context from the meeting minutes (from July 09) probably entering with a 4-3 vote. The bill isn't quite as vertical as the first bird, though the bill is certainly much smaller than probably all but the first winter bird of the previous trio. The reported discussion of the bird by the committee ended with this gem of a statement: "All agreed that the distinction between hybrids and pure birds is a murky issue, with some birds hovering around what are certainly arbitrary standards for acceptance."

But, the committee's headaches didn't stop there, they continued with the flock Tim found from the same day:

Birds 6, 9, 10, 11, and 14 were apparently accepted on the first round of voting. The birds were really too distant to get solid pics and Tim and I never collated our pics to figure out which numbers some of the sub-group pics corresponded to. Ironically in the field I thought number 10 seemed a little bigger than the others, I thought all the others were within the limits of what most Ross's-types in Michigan look like. Apparently after the ensuing discussion (where some members were no longer sure they supported some of the original birds), the minutes reveal that the committee took a break.

Finally, here's a bird from Washtenaw that's a clear hybrid (there were 2 like this at a Galien farm pond in Berrien last spring) with an evenly convex outward bill base, though still with some blueness to the bill base.

What to make of all this? Some birds, such as the last one, are obvious hybrids and are indeed intermediate between Ross's and Lesser Snow Geese. In my last Ross's post I mentioned how one paper (Trauger et al) and Pyle present similar measurements for hybrids and yet come to different conclusions, Trauger feeling that F1 hybrids can very much overlap "pure" Ross's and Pyle leaving a person with the feeling that they're more intermediate.
Before we get to that I think it's instructive to review the more studied Lesser Snow Goose over the last century. At the beginning of the 1900's the bird we now call the "Lesser" Snow Goose (the "Greater" subspecies breeds even higher in the arctic and winters on the east coast) was thought to be 2 species, the Blue Goose and the Snow Goose. Blue Goose wintered on the Louisiana coast and bred on Baffin Island and eastern Hudson Bay whereas Snow Geese wintered on the Texas coast and bred along western Hudson Bay. There was apparently only a narrow range of overlap in the wintering range. However, during the period of 1910-1930, rice farming exploded in Louisiana miles inland from the former wintering areas and opened up a big new foraging area attracting both color morphs. The ensuing decades found that blue-type geese steadily appeared in the western breeding areas and snow-type geese started appearing in the east. Cooke et al, 1975, describes that in smaller breeding colonies this process was accelerated, as up to 50% of the birds were born in different colonies from where they bred. The birds pair-bond for life on the wintering grounds during their 2nd winter, with females usually returning to their natal areas to breed with their mate following. (The young birds making their first trip north apparently mill about the edges of the breeding colony as non-breeders). The bottom line is that in a relatively short period of time a fairly significant change occurred across the Lesser Snow Goose population. (For more reading see Cooke et al, 1988, though it's a lot denser).
What of Ross's goose in this period? Well, a pretty tremendous population explosion occurred. One online reference suggests that the Ross's Goose population went from 2500 birds to about 1,000,000 birds over the last 60 years (though I have no idea where that figure is pulled from). We know that different populations of Snow Geese have been moving about in the last several decades. The birds pair up on the wintering grounds and Ross's Geese families are observed to be less able to stay together in a cohesive unit in the wintering grounds than Snow Geese according to Jonsson and Afton 2008. Trauger et al 1971, describes how years with late thaws leave the arctic nest sites at a premium leading Snow Geese to usurp the nests of Ross's Geese. Rather than going to the trouble of destroying the Ross's eggs and then having to remove them to a remote location to avoid attracting predators, they simply add their eggs to the nest and if Ross's goslings hatch they imprint on the Snows! Weckstein et al, 2002 also describes some degree of shared mitochondrial DNA between Lesser Snow and Ross's Geese in Louisiana.
I think it would be an interesting study to go through hunters' bags in Arkansas/Louisiana, New Mexico, and California and see what would shake out in terms of measurements of the birds and how they would compare with the studies done 30 and 40 years ago. My guess is that "Ross's Goose" in the east is a different bird now than it was a hundred years ago. As to whether the appearance of these birds in the east will stabilize or just continue to degenerate over the next decades will be interesting to see.
Cooke, F, CD MacInnes, and JP Previtt. Gene flow between breeding populations of Lesser Snow Geese. Auk 92: 493-510. 1975.
Cooke, F, DT Parkin, and RF Rockwell. Evidence of Former Allopatry of the Two Color PHases of Lesser Snow Geese (Chen caerulescens caerulescens). Auk 105: 467-479. 1988.
Jonsson JE and AD Afton. Lesser Snow Geese and Ross's Geese from mixed flocks during winter but differ in family maintenance and social status. Wilson Journal 120 (4): 725-731. 2008.
Trauger, DL, A Dzubin, and JP Ryder. White Geese Intermediate between Ross's and Lesser Snow Geese. Auk 88: 856-875. 1971.
Weckstein JD, AD Afton, RM Zink, and RT Alisauskas. Hybridization and population subdivision within and between Ross's Geese and Lesser Snow Geese: A Molecular Perspective. Condor 104(2): 432:436. 2002

Wednesday, January 6, 2010

A Long-eared's resolution

was apparently to be less bashful.

Long-eared owls can be found at times in late fall and winter with considerable searching and difficulty in the Sarett pine stand. However, a couple have been present in some of their cedar copses recently (breaking Tim's 6 year streak of not finding owls in them). We were amazed to find one 10 feet from the boardwalk essentially in the wide open this morning. I've never seen a wintering bird this exposed. It seemed to consider us to be weird deer or something as it opened its eyes halfway, but remained relaxed with its head settled low in its scapulars.
The red flecking in the right ear tuft and left breast is an artifact of either dust or snow on the scope and wasn't present in life.

Here's the bird taken without the scope, just the 4x zoom on the camera.

As a comparison, here's the 2nd most exposed I've ever seen a long-eared. This one for whatever reason had a lot more dark streaking to the underparts than others I've seen.

Tim's guess was that the bird will probably end up roosting in the pines where they have far more cover (and are infinitely more difficult to find).