The fall in fall migration
by Greg Mayer
For many bird watchers, the fall migration is the most exciting time of the year, as passage migrants, the arrival of winter visitors, and breeding birds in juvenile plumages, add to the diversity of forms, colors, and species that can be observed. For the birds, unfortunately, the fall migration is a time of high mortality, which is increased by the presence of human structures and lighting across the landscape. Many birds fly into buildings, cell towers, and other structures, and fall, dead or stunned, to the ground. Here’s a stunned bird I found with my vertebrate zoology class yesterday morning at 8 AM in front of a building. Note the closed eye and the drooping wing.
Fall warblers can be hard to identify, so much so that many bird field guides come with a section entitled “Confusing Fall Warblers“, or something similar. I will leave it to readers as an exercise, to identify this one. The following photo might help, as it shows more of the ventral coloration.
I picked him up, and moved him away from the door to the top of a rock (elevated so as not to get stepped on, and perhaps slightly harder for a passing cat or other predator to find).
After class was over, at 9:30 AM, I checked and he was gone. He may have recovered sufficiently to fly away. My understanding, though, is that birds that fly off have often sustained sufficient injury to their heads that they succumb a few days later.