Elusive Marsh Bird Callback Survey

Summer intern Molly Mullen paddles up the Bantam River at dawn

White Memorial Conservation Center is conducting a callback survey for elusive marsh birds as part of a nation-wide project coordinated by USGS and the US Fish and Wildlife Service.   We are looking for black, sora, Virginia, clapper and king rails, as well as the American and least bitterns and the pied billed grebe.  The survey has two routes, one walking and driving to different points, and one taking a canoe down the Bantam River.  For each survey, several points along the routes are selected, and at those points we play recordings of different marsh bird calls, separated by periods of silence.  The survey must begin at first light, half an hour before dawn.  This time of year, males are setting up territory and defending it against rivals.  By playing a call, we’re announcing ourselves and possibly challenging the boundaries of established birds.
            Hopefully, they will rise to the challenge and call back.  Odds are that several of the species on the CD would not even be present at a freshwater marsh so far inland, but even the rails we can expect to find here, like the Virginia rail or the sora rail, are difficult to find.  We may not ever actually see them, and even hearing them is unusual.  They’re cryptically colored in earth tones, not very big, and extremely shy.  It’s hard to tell whether or not a species is in trouble if you never see them.  Recent data shows a decline in populations of many marsh birds, making it all the more important to keep an eye on their populations.  These birds can act as indicators; we learn about how the marsh is functioning as habitat based on what birds are choosing to use it.  So far, we have detected Virginia rails at two locations, and a sora rail at one.

No comments: