Saturday, September 2, 2017

Rock Wrens

This morning, on my regular birding walk at South Platte Park, I encountered a rock wren, foraging on a spillway.  While these small songbirds are common in canyons and on rock outcrops and boulder fields of the Front Range foothills and mountains, I rarely see them down on the Piedmont.

Found throughout western North America, from southern Canada to Mexico and from the High Plains to the West Coast Ranges, rock wrens are identified by their pale gray coloration (except for a light, rusty wash on their lower abdomen), a long, thin bill, a barred tail and short legs.  Almost always found on rocky slopes or boulder fields, they hunt for insects and spiders, bobbing over the rocks, searching the crevices with their bill or springing into the air to snare their prey.  As one might expect, these vocal birds place their nest within rock crevices, using dried vegetation, sticks and bark chips to build a shallow cup; of interest, they also construct a "patio" of pebbles at the entrance to the crevice.

Come autumn, rock wrens depart the northern half of their summer range (including Colorado), heading for the Central Valley of California, the Desert Southwest or Mexico.  I suspect this morning's visitor at South Platte Park was beginning that biannual trek.