Finches crave salt. To satisfy this, mixed flocks of hundreds of them will alight on salted winter roads and feast. There is, of course, a problem with this: traffic. Indeed, some truckers refer to them as grill birds, owing to their propensity to be collected by the grills of passing vehicles.
It turns out that highway traffic is not the only thing that collects finch carcasses.
This is a view into the midst of perhaps a hundred finches on the highway. Both Pine Siskins, and Cassin’s Finches are seen here as they land, feed, and take off.
The problem, of course, is traffic. The birds try to lift off. While many escape, only to return, not all make it. There is a corpse in the lower left.
As the finches feed, ravens assemble and watch for roadkill. When it is spotted, they sweep down and carry off the corpses. This raven has a male Cassin’s Finch.
This one is packing a female Cassin’s Finch. As the raven flew off, it collided with a male Cassin’s Finch trying to escape the mayhem. (I interviewed one of the ravens about this. It prevaricated: “We have a contract with Highways to keep the roads clear of bird carcasses — yum yum.”)