Dead stuff Quiz answers

13 12 2011

A flurry of guesses came in on this quiz; thank you everyone! This kind of class participation warms my blogging heart. Here’s what I think on the 3 specimens:

Non-breeding Horned Grebe with head still attached. Very like our Bird A.

Pied-billed Grebe's bill is the same overall length, but with a much deeper base.

Alternate view of Specimen C showing overall size and white "bib" fur.

Specimen A: Everyone knew this was a grebe (the lobed feet being the give-away). But to get to species, we must examine the severed head lying near the left side of the carcass. Specimen A shows a black crown with a sharply demarcated white cheek. The bill appears slender. These characteristics mark it as a non-breeding Horned Grebe. The other possibility based on size would be the Pied-billed Grebe. While that species has a bill of almost identical length as the Horned Grebe, the Pied-billed’s is much deeper, giving it a short, chunky appearance. The Pied-billed’s face is generally a brown or gray wash, with no clear black crown.

Specimen B is a diminutive character, diminished even more by the loss of most of its flesh to a predator. What remains is sufficient to make the i.d. though. The black upperwing with white trailing edge to the secondaries mark it as an alcid. (Other candidates like the Bufflehead would have a wider white band, known as a speculum, on the wings). Within the alcids, only the dovekie is this small, with a foot barely wider than a human thumb.

Specimen C: A mammalian interloper in our quiz. I confess to very little knowledge of mammal i.d., so here’s my thought process. You are free to argue with me!

First things first: this is a member of the weasel family, showing the pointed head and carnivorous teeth of that group. The striped skunk will be the most familiar weasel to many of you readers, but several species of weasel are quite common here in New England. Specimen C is brownish overall, with darker fur over the rump and tail. In the additional photo shown here, a white bib of fur is evident between the forelegs. This coloration is consistent with the fisher, the second largest member of the weasel family around here (the river otter being largest). The size of Specimen C could be estimated in the original photo by the presence of the index card (presumed to be 5″ in length). Based on that, Specimen C is quite large–about 30″ including the tail. That puts the animal solidly in the fisher range. The American mink, the other candidate here, would be substantially smaller, maxing out at 20″, tail included. The mink would show a darker, more uniform color to the fur (which is partly why its pelt is so prized).

Perhaps the most interesting thing about Specimen C is the location where Dennis found it. Fishers have been expanding their range in New England, but their presence was not confirmed on Cape Cod until 2006. Now, Dennis has found one at the very tip of the Cape in Provincetown. Fisher were once thought to rely on unbroken forest canopies for survival, but sightings are on the rise in more open habitats, including suburban backyards. It appears that fisher may be more flexible and adaptable than once thought. That’s good news for them, and for all of us who admire these dauntless and fierce predators.



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