disappearing birds?

I recently wrote about the morning silence in the marsh now that the Red-winged Blackbirds were gone. A couple of readers were seriously concerned by what they took to be a report of the apparent disappearance of this common bird, thinking that it might be a part of the Sixth Extinction currently in progress. I didn't intend to give that impression. Red-wings (and their close relatives, Common Grackles) are still common breeders around here and the Red-wings in particular had a very successful breeding season, as evidenced by the numbers of young birds that turned up this summer. The adult male Red-wings are strong defenders of territory, preferring the edges of wetlands but also upland meadows. They mark their territories with their characteristic trills and also by flashing their colorful shoulder patches and they will attack intruders -- including at times, humans -- by diving at them noisily with their sharp beaks as a threat. Females will also sometimes drive off other females but it is common for several females to establish themselves in a single male's territory; apparently the attraction is the territory itself rather than the handsome male! Since each nest has 2 to 3 eggs, the result is a lot of young fledging out of nests that are situated in a good territory!

In mid- to late summer, the males gradually abandon their territories -- I have often noted how they get less and less aggressive -- and the birds, young and old, start to form large flocks, often with other blackbirds. These flocks tend to gather at designated roosting sites, often in stands of phragmites at the edge of a marsh. Shortly after sunrise, these flocks disperse in groups of a dozen or more in search of good feeding areas and they will tend to return to their roosting area at sunset. In past years, there has been a fall or winter roost in the dense reeds at the edge of our marsh but that doesn't seem to be happening this year -- at least, not yet. It's possible that the memory of last winter's cold has already sent many of the birds further south to look for more congenial roosting or feeding areas. It's still early though, so we'll see what happens.

Frank Quevedo, the SOFO director, similarly mentioned to me that he hadn't been seeing any American Robins since their breeding season came to an end. The explanation is actually similar. Robins, young and old, also cluster into feeding flocks at this time of year and, as their Latin name (Turdus migratorius) suggests, tend to move south as the weather gets colder. At the moment we have small flocks of Robins, some of them with the spotted breasts of young birds; they are feeding on the profusion of berries -- Pokeweed, Poison Ivy, Tupelo -- that marks the end of summer in these parts. 

Eric Salzman