Dead (____) Quiz answers

25 07 2014

My thanks to Capt. Eagle Eyes, the sole respondent on this quiz! Let us begin. Bird A, no one had any guesses on. At first, I felt the same and hung my head in despair. Then I realized that the foot was quite visible and might be of some aid. Sure enough, the long foot and very flattened, blade like tarsus leapt out at me on closer inspection. This told me I was looking at a loon. This impression was reinforced when I looked at the white belly and breast, white underwing, but with a little glimpse of some pale flecked upper wing feathers. So, a loon. Which kind? For that, I had to rely mainly on the reported wing chord, which was small and set the this bird solidly in the Red-throated Loon range. I feel fairly confident about this one.

Bird B, how about this one? The Captain suggested scaup, and I see his point (I am merely assuming, Captain, that you are male); this bird has a dark head, dark over the breast and a fairly standard looking duckish bill that could easily make it a scaup. However, the case is complicated by decomposition. This bird is falling apart, and, looking closely, we can see that the keratin sheath has fallen off the upper bill, exposing the bone underneath. The outline of the bill (completely vertical at the base where the beak meets the feathers) and the shape of the missing sheath piece makes me suspect that this bird is a Black Scoter. The missing piece was likely the yellow knob that males develop, which would be consistent with this bird’s gradual acquisition of adult male black feathers over the breast. My guess, therefore, is that this is a subadult male. Since we are on the subject of adolescent male Black Scoters, I want to share with you this rather striking photo of a bird found by Gil Grant in North Carolina last month:

Black Scoter male showing very prominent wearing of belly feathers. (Photo by G. Grant).

Black Scoter male showing very prominent wearing of belly feathers. (Photo by G. Grant).

This bird gives us a glimpse into the process of acquiring adult male plumage. The bill has turned quite yellow, but has not entirely become the raised knob seen in full adult males. The belly is almost entirely white. This phenomenon occurs as the bird grows in strong, new, black feathers over the back and breast first, while the older, weaker, belly feathers persist for longer and tend to rub and break. This bird may have been stranded on the beach for a time before dying, and the abrasion of sand and rocks may have accelerated the wear of those feathers, exposing more of the white bases and underlying down.

Another view of the new, black feathers coming in over the back, and the yellow bill base. (Photo by G. Grant).

Another view of the new, black feathers coming in over the back, and the yellow bill base. (Photo by G. Grant).

For Bird C, the Captain suggested Surf Scoter, and I do think this is a scoter. I am trying not to be biased by the fact that we have had such a high number of Black Scoters turning up on southeast beaches this year, but I still think this may be yet another one. Not a lot to go on here, as the carcass is quite degraded, but we do have a clean skull to go on. When I am faced with nothing but bones, I like to refer to Wouter’s Skull Site. Take a look at the Black Scoter skull page. Call me crazy, but it reminds me strongly of Bird C. I also looked at Surf Scoter, and Common Eider and White-winged Scoter, but I’m sticking with my original thought on this one.

Now, we come to Extra Credit. I don’t know much of anything about non-seabird beach cast remains, but that has never stopped me from holding forth before. Looking at this bone, I noted the little peg-like projections along the long edge, and I began to suspect we had a mandible here. It looks like a marine mammal to me, and the Captain thought bottlenose dolphin, which was right along the lines I was thinking. The only problem seemed to be size. This bone is only about 4 inches long. When I started looking into it, it also seemed that the teeth of a bottlenose are quite long and slender, not peg-like as in our specimen. What else could it be? Not a seal–they have a very dog-like tooth pattern–not these regular little pegs. Could it be some kind of small porpoise? I know there are people with lots of expertise in these sorts of things who would readily identify this thing. Where are those people? Am I wrong about the length of a bottlenose’s jaw? About the tooth shape? Is Captain Eagle Eyes right? I don’t know. And it’s a beautiful day and my children are agitating downstairs with increasing ferocity, so I must leave you there, dear readers. Until next time, when I may, perchance, have learned more about that Extra Credit bone.

About these ads

Actions

Information

3 responses

28 07 2014
capteagleeyes

My name is James Taft, my moniker is Capt Eagle Eyes.

Date: Fri, 25 Jul 2014 14:43:10 +0000 To: j.taft3@hotmail.com

29 07 2014
scourc01

Pleased to make your acquaintance! It is an excellent moniker, Mr. Taft.

4 08 2014
Wouter van Gestel

Sorry for being late, due to a family holiday in a cabin without laptop, tablet or smartphone, but I know that mistery bone in the last picture. It is a fish bone, more precisely the first bone of the leading edge of the pectoral fin of a pretty large fish. I cant tell you the species, but it’s probably a fish over 1 m long, maybe a cod.

Wouter

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




Follow

Get every new post delivered to your Inbox.

Join 59 other followers

%d bloggers like this: