THE CORVID SHIFT

It's time to update my post from a couple of years ago about the shifting local populations of ravens and crows. Common Crows (Corvus brachyrynchus) colonized Salt Lake City just seven years ago, and Ravens (C. corax), common denizens of the deserts to Salt lake's south and west, began to nest in small numbers in the city around 1980. Over the first three years, the crow population rocketed to a few hundred birds before seeming to level off around 2005. Ravens, on the other hand, have never numbered more than a few pairs in the city itself.

I grew up in the Wasatch Mountains east of Salt Lake, and never saw a Raven in the Wasatch, north of Utah county, until last year's Blogger Bioblitz, when I watched a pair emerge from a draw to stoop at a passing goose. A thorough search of the area failed to yield anything, and I assume they failed to nest there. This past week, another pair (perhaps the same one) was observed on multiple occasions in the next canyon to the south. So far, I've been unable to locate a nest.