The redpolls are coming!

I have stocked bird feeders for winter visitors for many years and set up several feeding stations around Willow House this fall.   It took a while for the birds to discover my feeders, but the usual suspects now include my stations in their rounds.  Mourning doves, juncos, chickadees, goldfinches, and woodpeckers are all regular visitors.  However, the Common Redpolls (Carduelis flammea) are my favorites.  This owes, in part, to the fact that redpolls, as an irruptive species, can’t be counted on arriving every year.  Irruptions usually occur biannually.  In these years, a set of northern species, including redpolls,  move south for the winter, probably driven by food shortages.   I set two tube feeders for niger seed within viewing range of the living room window in the hope that redpolls would find my supply, and indeed they have.

Redpolls, as their name implies, are readily identified by their red caps.  Their distinctive black bibs are also helpful identifying features.  They are querulous little birds and seem to spend as much time squabbling and chattering as they do eating.

Energy reserves for birds roosting at night may consist of relatively large amounts of seed in their crops, but the primary energy reserve for most species is body fat.  However, redpolls have evolved a special pouch located within the neck called an esophageal diverticulum.  Extra food can be stored here towards nightfall and regurgitated as needed.  This helps to make these tiny birds one of the most cold-hardy species.

Males can be distinguished from females by the flashy rose colouring on their breasts, which becomes more vivid as spring approaches.