August 31, 2012
What's that Bird of Prey Eating?
We've had another visitor at the pond. Since it's a bird, Kimball was kind enough to write this week's post!
"Cooper’s Hawks, Accipiter cooperii, such as this adult, have frequently been recorded by Sam Easterson’s “camera traps” as they drink and bathe at the Natural History Museum’s North Campus pond. These hawks are among the most conspicuous vertebrate predators in urban Los Angeles – a significant turn of events given that this species was on the National Audubon Society’s “Blue List” as recently as the 1970s. The “Blue List” – a sort of early warning list of potential endangerment – included species “suffering population declines or range diminution in all or parts of their range.” Cooper’s Hawk populations have rebounded spectacularly in part because of reductions in the use of certain pesticides, but also because they are now rarely persecuted as the pest their nickname “chicken hawk” alludes to.
But the increasing population of Cooper’s Hawks in our region is not without ecological consequences. These hawks, and other species in the genus Accipiter, are bird-eaters – they catch songbirds, doves, and many other kinds of birds by ambushing them with short flights over and through vegetation. We don’t know the extent to which declines in populations of some urban bird species (such as the introduced Spotted Dove, which is now virtually gone from southern California, or the Inca Dove, whose population in the Tucson, Arizona region has plummeted) can be attributed by increased predation pressures by Cooper’s Hawks. Careful observations by scientists and citizens – and Sam’s technological wizardry – may help us better understand the role of predators such as the Cooper’s Hawk in regulating populations of their prey species."Thanks Kimball! Finally, here's some footage Sam's trap captured of the hawk taking a bath in the pond!