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.”)
Drama on the highways! Thanks for bringing more interesting info to our screens, Alistair.
Helen
Pollyanna here: Could salt not be generously spread a safe distance from highways, in key areas??
The realists might say, “Transfer of energy, finch to corvid”. Fat lumbering clever Ravens.
There. Anyone feel better about those dead and dying little finches who will not be nesting in the spring?
Pollyanna signing out, reaching sadly for a tissue ….
But oh, what stunning images. Macrocosm/microcosm: I’m reminded of the great frontline war photographers, capturing the tragedies that haunt the viewer for a very long time.
It’s unfortunate salt is used on highways not only because of terrestrial wildlife mortality – also moose, deer etc., but because of the harm it causes in mineralizing aquatic ecosystems in run-off, jeopardizing all manner of aquatic life and ultimately reducing biodiversity.
Where would finches normally get salt if no road salt?
Great photo in pictures again! I didn’t know this about Finches! I have never noticed this in my area!
Awesome action shots, Alistair! I’m a newcomer to your blog and am loving every post! Very pleased to be able to tag along on your Kootenay Lake adventures!
I believe that the finches are harvesting sand granules and not salt. The amount of salt needed in most birds diets are nearly Zero. Grit for gizzard function is however a major problem in snow-covered environments.
Bill, it may be that this is not a case of either one or the other. In some past postings, I have stressed grit. Yet, this time I rechecked a number of authoritative sites (such as Cornell’s) and learned that these finches crave salt whether on roads or salt licks. Alas, only a few sites even mentioned grit. So, why do these finches alight in large numbers on dangerous winter roads? It is unclear, but I am beginning to lean primarily towards salt.