ENGLISH SPARROW UPDATE
A couple of years ago I wrote about the North American introduction of English or "House" Sparrows (Passer domesticus) and a few of the ecological effects of that act. English Sparrows, especially fledglings, are far easier for predators to catch than any native bird, a fact that I believe is responsible for a number of behavioral changes I've noticed in other creatures, most notably American Kestrels (Falco sparverius). Here in Utah, kestrels living in human-altered ecosystems feed heavily on young English Sparrows in the summer, and tend in general to be much more ornithophagic than their wilderness-dwelling brethren.
I once saw a Raven (Corvus corax) fly down an English Sparrow, and imagine that could be common behavior in some situations. This morning I added another species to the list of species I've seen benefit from the little immigrants. An adult Black-billed Magpie (Pica hudsonia) caught a fledgling English Sparrow on a suburban lawn and flitted over the rooftops with its prize.
upper: AMERICAN KESTREL & ENGLISH SPARROW (2007) acrylic on illustration board 30" x 20"
lower: CRASH-BARRIER WALTZER--BLACK-BILLED MAGPIE (2005) acrylic on illustration board 30" x 22"