Tracking scoter mortalities

26 06 2014

In mid-June, our favorite duck hunter, Jack Renfrew, wrote to tell us that his son had seen about 50 dead Black Scoters on the rocks near Woods Hole, Massachusetts. This past week, we received an email passed along by Rick Keup down in South Carolina letting us know that the state wildlife authorities were looking into scoter die-offs on their shores as well. Their agency managed to get a few carcasses and have shipped them to the National Wildlife Health Center in Wisconsin for diagnostics. Hopefully, we’ll have some answers for you soon, but as we’ve learned time and again in such cases, there may be no clear answers in the end.

In the meantime, we’re left wondering. Is this scoter phenomenon the same in the north versus the south? Is there a difference in age or sex between the northern and southern birds? In body condition? In a whole host of other factors?

Because I am a nerd, my birthday present last year was this informative but not very flashy volume:
IMG_5803

In it, I have learned that Black Scoters tend to venture farther south in the winter than our other scoter species, with substantial numbers (up to 30,000 birds) found as far south as Georgia. There are reports of the birds even in Florida in eBird, though the species is comparatively rare there. The heart of their wintering terrain runs from Maine to Virginia, in any case, so South Carolina is certainly pretty far south for them. As for timing, the species breeds here in the East on lakes from Ontario to Labrador, and they mass for that northward migration in the St. Lawrence starting in mid-April. By mid-May, most of the birds have traveled to and are headed onward from the St. Lawrence. By the end of June, few birds would be expected to remain down south, and eBird records tend to reflect that:

Screen Shot 2014-06-26 at 11.56.38 AM

The Nisbet et al text reports that “very few (usually <10 together) oversummer in the main wintering areas off the eastern United States." Any birds still remaining in the southern states at this point in the year, then, may well be abnormal. But are these birds starving? Sick? Ill-equipped to make the migration or to attempt breeding? There has been some chatter along these lines amongst the birders and wildlife pros contemplating the problem, and factors like this winter's harsh weather and its impacts on sea ducks have been bandied about. Nathan Dias, who birds the southeastern coast, wrote,
"This is the second summer in a row that numbers of Black Scoters over-summered in SC. Some have been lethargic and spent a lot of time on the beach, while others have looked healthy and hale all summer long. John Cox, Chris Snook, I and other CRBO folks saw them in multiple locations in Cape Romain NWR last year (Key Inlet, Marsh Island, north Bulls Island) and down at Kiawah and Sullivan's Island as well. But there are definitely more of them this summer – they are all over the SC coast."

Whether we're looking at a couple aberrant years, or a new normal remains to be seen.

As we learn more, I will be certain to share it along, my dear readers.

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Curiosities in Maine

23 06 2014
Ralph Eldridge, lighthouse keeper at Machias Seal Island, took this photo of the rarity.

Ralph Eldridge, lighthouse keeper at Machias Seal Island, took this photo of the rarity.

This is not unusual since Maine is full of curiosities generally, but this time, both are bird related. The first is the story of a Tufted Puffin turning up on Machias Seal Island last week. “Yes, yes,” say the uninitiated, “a puffin in Maine. This is <yawn> big news.” But those puffins we have up on the rocks off the coast are Atlantic Puffins. This Tufted variety is a Pacific bird, and the last time one was spotted anywhere on the Atlantic side of North America was in the 1830s. There was a sighting in Sweden in the late 1990s, and another in Britain in 2009. Given the long lifespans of these birds, there has been speculation that that was the same individual.

The bird seen in Maine this month has been hanging around with its Atlantic cousins. How it got here is a mystery, but we do know that to make the journey from the Pacific over to Maine would require that the bird remain near open water to feed. It could not have traveled across the continental land mass. That leaves the possibilities that it flew along the coast of South America, rounded Cape Horn and then came all the way up to Maine, or that it potentially crossed via  a Northwest Passage through the Arctic. If this is the case, scientists speculate that we may see more Pacific interlopers as those paths remain ice free more of the year due to unremitting climate change. The cascade of consequences from our activities continues to surprise.

The second curiosity is a dead bird found by Doug Hitchcox on Ogunquit Beach earlier this month. Here’s the message he posted to the Maine birds list regarding the find:

 

“Hey everyone:

After summarizing our spring rarities in my last email, I thought the best
birds were past us, I was wrong. (By the way, I did forget that Kristen
Lindquist had a White-eyed Vireo on Monhegan Island, Lincoln Co. on 17 May.)
While surveying for plovers along Ogunquit Beach on Tuesday (6/10), I found
a dead pterodroma petrel that I believe is a Herald (Trindade) Petrel.

I know I’ll never hear the end of it, but I do not have the specimen. After
finding this bird, I took a few photos and saved the lat/long of where the
bird was (43.255417, -70.59175) so I could finish my survey. Later in the
day, Robby Lambert and I returned to recover the bird but could not find it.
I can’t thank Robby enough for the help as we looked all over the beach with
flashlights, finally giving up a little before midnight. I, and others, have
been back in the days since, searching to no avail. The lesson here: if you
find a dead rare bird on the beach, just carry it around with you for the
rest of the day.

I look forward to hearing from some pros, or someone with more pterodroma
experience than I, but here are a few of my thoughts on the identification,
starting with a photo:”

Photo by D. Hitchcox

Photo by D. Hitchcox

What do you think, Seanetters? I know it’s not something we’re accustomed to seeing, but we do have a unique skill set for identifying dead birds, no?





Dead Bird Quiz answers

17 06 2014

First off, the easy one. All respondents (and there were many this time, thanks!) pegged this one as a Sooty Shearwater. For the i.d., I registered two things–clearly a tubenose beak, and the underparts (belly and breast) are all gray. This latter characteristic sets it apart from the other shearwaters, as they have either entirely white underparts, or mostly white (Greater Shearwaters have variable smudging on the belly). The mini tubenoses, like storm petrels, may also have dark underparts, but those guys are tiny and not like our Bird B.

Bird A didn’t seem to stump many people either, despite the lack of a head. For me, what I looked at first was the broad body, looking almost wider at the back end than through the breast; legs set far back on the body; and short, but broad wings. These things together say “diving duck” to me, and the options are typically scoters or eiders (and they’re pretty uncommon so far south). Mergansers would usually have a slimmer body overall, and the feet look too dark for them anyway. So, scoters. White-winged can be ruled out since our Bird A lacks the eponymous speculum. That leaves us with Surf Scoter and Black Scoter. This is a call I have to make often, and it’s not always easy when the head is missing. Wing chord is not a lot of help, since both fall in the 20-25cm range. There is a little trick that is sometimes useful when the outermost primaries can be seen clearly: in Black Scoters, the outermost primary is shorter and narrower than the next two, while in Surf Scoters, it’s longer. This can be subtle though, and when one is working from a photo, it may not be a helpful point at all. I do find the feet to be sometimes helpful, and Black Scoters have darker feet than Surf Scoters, even when young. Male Surf Scoters tend to acquire their reddish feet rather early, in my experience, and Bird B’s feet, by contrast, are very dark.

Mary Wright cited one of my favorite sources for making these calls: Peter Pyle’s Identification Guide to North American Birds, Vol. II. Mary pulled out these characteristics as being decisive in this case:

“Bird A: Black Scoter, second-year male. Species indicated by shape, size, and primaries that are paler on the underside. SECOND-YEAR because: dark upperparts and breast “contrasting distinctly with pale brownish abdomen, the latter wearing to whitish by May-Sept” (Peter Pyle, Identification Guide to North American Birds, Part II, pp 138-139); older birds have dark brown abdomen. Second-year MALE because: “upperparts and breast brown, increasingly mixed with blackish feathering … in Dec-Sept” (ibid); in SY females, brown upperparts and breast are “increasingly mixed with darker brown feathers in Nov-May” (ibid).”

Adult female (left) and adult male Black Scoters. Note that neither one has a pale belly like our Bird A. (photo by Kurt Hasselman)

Adult female (left) and adult male Black Scoters. Note that neither one has a pale belly like our Bird A. (photo by Kurt Hasselman)

Wouter wrote that it appeared to be a very faded female Black Scoter to him, and that raises a good point. That very pale brown color to the wings and back–is that real, or an artifact of time and weathering? Indeed, looking at the feet, they are contracted and dried out, almost mummified, indicating that this bird has been dead a good long time. We do see plumage bleach with time, so identifications must be made with a nod toward that phenomenon. But what IS clear from these photos is that the feathers replacing the old brown ones are coming in black (this is best seen over the back). That, as Mary points out, makes this a male, as in a female, those new feathers would be growing in brown instead.

This has been a good one for me to puzzle through, pondering each characteristic in turn. It’s impressive how far along one can get with a headless bird, no?

And now, I must go back to trying to finesse my pack for an end-of-school backpacking adventure with my sons. And they can’t carry much, so smart packing is going to be key here.

I leave you with something else Mary Wright shared with me, and which I, in turn, am sure you’ll want a look at. Some strange nest fellows these…

Peregrine rearing unexpected chicks





Dead Bird Quiz: sand-caked in the Carolinas edition

13 06 2014

We’re coming into the summer season now, when we routinely see far fewer bird carcasses turning up on the beaches. But fewer doesn’t mean none, and this week, I am able to bring you two birds for the quiz. The first, found by the Lori Porwoll in South Carolina this month, is headless and looks like it’s seen several miles of bad road.  The second, found my Gil Grant this month in North Carolina, is in somewhat better shape. What say you, Seanetters?

Bird A (photo by L. Porwoll)

Bird A (photo by L. Porwoll)

Bird A, ventral surface

Bird A, ventral surface

Bird B (photo by G. Grant)

Bird B (photo by G. Grant)





Return from Appledore, and other news

9 06 2014

Thank you for your forbearance over the past few weeks as my blog posts have grown few and far between. I have come back from gull banding now, and the week’s weather out there turned gorgeous in the latter half, so we were working through most of the daylight and often doing data entry well past. If you are not already a reader of the Gulls of Appledore blog, please take a look for more on what we were up to, and about the larger gull ecology study of which we were but a small part.

Now, I am back on the mainland, clean, and with supplies reorganized. I was also caught up in a flurry of job interviews which concluded in an offer made and accepted. Come fall, I will be teaching full time at Northern Essex Community College in Massachusetts!

Never fear though, Seanetters; it is my intention to continue on with this program that I love so much, and with all of you volunteers whom I hold so dear. It’s only a matter of finding some more funding to keep us going. Should you know of any grants or other potential funding sources, let me know; I will be turning at least part of my attention to ferreting out such monies. For now, I leave you with these two mementoes of my week in the field with some excellent students who worked hard, maintained good humor, and were surprised at how much they’d learned by the end. I can’t ask for better than that. First, our formal portrait. And second, this can’t miss video of why we enter the colonies either helmeted or bearing big sticks to divert attention from our vulnerable skulls: Sean vs. Herring Gull

Gull team, May 2014: From left: Bill Clark, Sean Jeffery, Sarah Courchesne (me!), Sarah Chieng, Carly Emes, Kristen W (whom we poached from another research project, which is why I only know her last initial.)

Gull team, May 2014: From left: Bill Clark, Sean Jeffery, Sarah Courchesne (me!), Sarah Chieng, Carly Emes, Kristen W (whom we poached from another research project, which is why I only know her last initial.)