Friday, June 29, 2012

Waiting for Groceries

Juvenile Cliff Swallow (c) John Ashley
Juvenile Cliff Swallow waiting for a food delivery
Apparently, I've never paid close attention to Cliff Swallows before. But while working around an old horse stables last weekend,   I couldn't help but stop and watch the swirling clouds above our heads. The adult swallows poured in and out of their mud-ball nests on three sides of the building.

The adults flew in dizzying circles, delivering delicious insects to their nearly-grown chicks. The juveniles watched too, from the opening in each active nest, waiting for the next parent to bring yet another taste treat. This working stables wore a necklace of several dozen swallow nests under each eve. It seemed like a lot of birds to me, but the largest Cliff Swallow colonies in the west can number 3,700 nests or more.

Cliff Swallow nests
(c) John AshleyYoung Cliff Swallows born in Montana will soon fledge from their nests and form creches with other juveniles. By August almost all of them will be winging their way towards South America, where they'll spend the winter. Why migrate so early? Because they only eat live insects, so they have to leave Montana before an early frost depletes their groceries.