Laura Erickson's For the Birds

Common Redpoll

(Recording of a Common Redpoll)

One bird that’s been around Duluth all winter which is finally showing up at my feeder is the redpoll. The redpoll is a tiny bird, streaked below, with a little black throat patch, a bright red forehead, and varying amounts of pink on its breast. It’s much smaller than a chickadee, but don’t let its fragile appearance fool you–the redpoll can survive temperatures colder than any other songbird known–67 degrees below zero!

How can a bird so tiny be so hardy? For one thing, it has a lot of feathers in winter. One ornithologist discovered that a redpoll’s plumage weighs 31% more in November than in July. The diet helps, too– redpolls choose seeds that are very high in calories–especially birch and alder seeds. They feed heavily at the end of the day–they can remain more active than most birds at very low light intensities, making their day a bit longer for fueling up. And they have storage pouches in the esophagus to hold food, allowing them to be adding fuel to their stomachs throughout the night.

Redpolls, as well as several other species of northern finches, don’t have the regular migration patterns of most song birds. Instead, they are called irruptive species–in some years, they are abundant, and in some years rare. They are probably following good seed crops, although in some years when there seems to be quite a bit of natural food present, they’re rare in the Northland. They are often found in huge flocks. So far this year, though, I’ve only had one or two at my feeder at a time. They are very tame–they often come close if you make pishing sounds.

(psh ph psh)

Unfortunately, this tameness makes them especially vulnerable to cats. Last winter I took in a stray cat that had been surviving on the redpolls at my feeder, and just last week I watched a neighbor’s cat snatch a redpoll on the street in front of my house–the redpoll had been attracted down to where a snowplow had dropped a load of sand. Redpolls, like all birds, have no teeth, so they can’t chew their food. Instead, they take grit into their gizzards, which helps pulverize the seeds they eat. I often see finches taking grit on roads in winter–and in my yard they spend a lot of time in my kids’ sandbox.

Redpolls virtually never come to mixed bird seed–the kind you see in grocery stores–they much prefer niger seed, which many people call “thistle seed.” Real thistle seed is not available commercially because it easily germinates into a noxious weed. Niger is native to India, and doesn’t germinate in the U.S., but our finches are just as fond of it as they are of real thistle. Unfortunately, niger seed costs about as much per pound as a good steak–partly because of the high cost of shipping from Asia. Fortunately, sunflower seed also attracts redpolls–after my squirrels destroyed my niger feeder a few years ago, I’ve limited my redpolls to sunflower seed and they haven’t seemed to mind.

(Recording of a Common Redpoll)

This is Laura Erickson, and this program has been “For the Birds.”