Saturday, January 14, 2012

Coot-Coot Put-put

One way to trip up beginning birders is to stand them in front of a bunch of waterfowl and ask them to name all of the ducks they see. This is the embarrassing - but memorable - way that many of us are introduced to our little grey American Coots (Fulica americana), birds that really belong to the rail family.
American Coot
power stroke (right)
and forward stroke (left)
(c) John Ashley
Right foot forward stroke (left) & power stroke (right)

Coots are “duck-like,” but they don’t have webbed feet and are not ducks. By contrast, all members of the rail family (Virginia Rail, Sora, Coot, etc.) have long, separated toes. But Coots take it one step further. Both sides of each toe have a fleshy, folding flap that makes swimming somewhat more efficient.

During each power stroke, the Coot’s toe flaps fold out and significantly increase the amount of surface area that’s pushing against the water, propelling the bird forward. During the forward strokes, the toes and flaps fold together, greatly reducing the resistance as the foot moves forward through the water, repositioning for another power stroke.

Because of all this toe-flapping motion, Coots put-put forward while swimming. This is glaringly different from the graceful swimming motion of real ducks - but Coots don’t seem to care.

Other indignities don’t seem to bother the Coots, either. One older bird book refers to Coots as “aquatic pigeons,” proclaiming them to be among the “least graceful” of all the marsh birds. But while Coots might appear to be ungraceful, they are the most common and widespread of all the rails - and clever to boot.

When researchers experimentally raised and lowered the air temperature between 50F to 104F, Coots were able to maintain a steady body temperature by moving in and out of the water with their radiator-like lobed toes. And even featherless humans can recognize the Coots' communication repertoire of at least 14 different body postures (not to mention their grating calls). The little Coots are also agile enough to pirate plant foods from the beaks of bigger dabbling and diving ducks.

Along those lines, when some good-hearted, beginning birders once discovered a Coot dragging tangled fishing line on one foot, they were unable to capture it with the combination of a long-handled fishing net, soothing “Here Coot-Coot” calls, and pieces of stale bread that any old Mallard would have fallen for. No, it wasn’t until they brought out the homemade peanut butter cookies that the Coot finally submitted to capture (and detangling).

So at the very least, non-duck Coots have good taste.