Interim Report #59: American Coot

“I come from haunts of coot and hern / I make a sudden sally / And sparkle out among the fern / To bicker down a valley.” – Alfred Lord Tennyson, “The Brook.”

Easily the most familiar member of the family Rallidae, the American Coot is a common sight in Massachusetts during the fall migration, when rafts of birds numbering in the hundreds can sometimes be seen feeding together.  As a breeding species, however, this species is primarily western and southern in distribution.  Its history in Massachusetts is a rather short one, and it may be the case that the final chapters are being written even as I type.

As the most aquatic of all our rails, American Coots require significant expanses of open water as well as emergent vegetation in their breeding grounds.  They prefer to breed in wetlands that stay wet year-round, since much of their diet is composed of underwater plants and algae.  The prairie pothole region of the American Midwest supports a huge number of the nation’s breeding coots, but they are also regular breeders in the southeastern states.  For a long time, Massachusetts was beyond the northern fringe of the American Coot’s breeding range, and there are very few records of any coots breeding in the Bay State until the 1960s.  Range expansion during the late 60s saw the first few breeding records in Massachusetts, and some of those birds (or their descendants) were still present during Atlas 1.

A modest showing, to say the least.  Parker River and Great Meadows National Wildlife Refuges were the only places in the state that showed signs of breeding American Coot during Atlas 1.  Still, Atlas 1 happened relatively early in the colonization process for American Coot.  The conditions in Massachusetts aren’t necessarily ideal; late spring can be so cold and wet that nests will fail even in good habitat.  Since their nests can be as well-hidden as any rails, this makes I difficult to know whether or not they are breeding, as the presence of chicks is by far the easiest way to confirm American Coot.  Still, these birds have had enough time to establish a stable breeding population in Massachusetts if they intended to do so.  Did they intend to do so?  The image speaks for itself.

Massachusetts remains on the fringe of the American Coot’s breeding range, so it’s not surprising that only one possible record has yet been reported for Atlas 2.  Many of Massachusetts’ permanent wetlands have been degraded by invasive loosestrife (which seriously reduces their usefulness to coots) and shrunk by development.  Coots will use temporary wetlands only in very wet years, and following a wet breeding season, the population typically experiences a significant boom.  Think of the southeastern United States as a big bucket of water with a bunch of American Coots floating on top.  When it rains a great deal, the bucket fills up and eventually spills some of the coots over the side.  I acknowledge that it isn’t a perfect analogy, but these “spillover birds” are the ones that we occasionally find breeding in Massachusetts.  Coots show little evidence of site fidelity or philopatry, so there’s no strong reason for coots that used to breed in Massachusetts to return here unless a population boom forces them to travel to the edge of their breeding range.  The few remaining large wetlands with robust emergent vegetation can probably expect to see the occasional pair of nesting coots in the future, but the establishment of a large, stable population of breeding American Coots does not seem likely to me in the future.

All historic information in the text comes from Mass Audubon's Breeding Bird Atlas 1 or the Cornell Lab of Ornithology's "Birds of North America" site (bna.birds.cornell.edu/bna) unless otherwise stated.

Photo credit: Mike Baird.  Licensed under the Creative Commons Attribution 2.0 License.

Comments

[Kirstyn Hallahan]

I live in Hanson, MA (Plymouth County) & have been watching one of these birds for a few months. I live on a river (which is behind my house , has a small current & grows lily pads..great for fishing) which leads out to one of the Twin Lakes of Monponsett. I have been tying to figure out what he was. I have ducks, swan, geese & blue herons back there as well. I have also been seeing a brown water bird, similar to a female mallard but with a mohawk on its head. Haven't been able to identify this one yet.

[Matt Kamm]

Thanks for the comment, Kirstyn! American Coots always pass through in large numbers during the fall, but seeing them in winter is rarer. During mild years such as this one, your neck of the woods is often the best place to see them in areas where the water remains unfrozen.

Your other visitor with the funky 'do may be a female Hooded Merganser (http://commons.wikimedia.org/wiki/File:Kappens%C3%A4ger_weiblich_0505052_wikiausschnitt.jpg) Like coots, they can be hard to find in the winter, but some of them turn up around the southeast coast every year.