Mystery Bird: Pied-billed Grebe, Podilymbus podiceps

tags: Pied-billed Grebe, Podilymbus podiceps, birds, mystery bird, bird ID quiz

Please name at least one field mark that supports your identification.

Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:

It's always a good idea to figure out just what parts of the bird you're seeing; it isn't always obvious. This chunky, lax-plumaged waterbird is in profile, with its aft end to the right and its breast at the left; the long neck is stretching over the back, the head busily engaged in some maintenance behavior or other. That great mass of greenish-gray rising over the back is a foot, raised to let the poor bird get to whatever itch it's scratching.

There isn't much of a tail -- an important character in itself -- so let's look at the foot. First glances to the contrary, the toes aren't webbed but rather lobed, each separate toe furnished with discrete flaps. I can't offhand recall how many families of birds around the world have developed this feature, but in North America it occurs in sungrebes, grebes, coots, and phalaropes. This bird's taillessness and its poorly textured plumage, along with the position of the feet clear back on the body, point us towards the grebes.

It isn't entirely clear how much of the head we're seeing, but the neck and whatever might be visible of the face is very plain, quite unlike the stark patterns shown by most grebes. The full breast and muscular neck point away from the spindly-looking grebes of the genus Podiceps, and the uniform color eliminate the "swan grebes" of the genus Aechmophorus. Least Grebe is also much more gracile, and its body plumage usually suggests an odd silvery-tinged bluish-gray rather than the mud brown of this quiz bird.

There's nothing here that doesn't fit Pied-billed Grebe, the best-known and second most abundant podicipedid in North America. But let's introduce an elegiac wrench into the works. Until a couple of decades ago, there was another Podilymbus grebe in North America, the Atitlan Grebe of Guatemala. Also known as the Giant Pied-billed Grebe, this extinct species was very like its smaller relative in appearance, so similar, in fact, that the identification of the birds involved in the final sightings is unclear and so the precise date of the larger species' extinction unknown. Probabilities aside, the warm brown of our quiz bird's plumage is unlike the colder gray typical of Atitlan Grebe, and we can rule that species out. Alas.

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