For the Birds Radio Program: White-crowned Sparrow

Original Air Date: May 20, 1988

Laura talks about a bird that scientists have poked and prodded and studied to make several interesting discoveries. (4:10)

Duration: 4′14″


(Recording of a White-crowned Sparrow)

New spring arrivals are coming in every day now. Hummingbirds arrived in Port Wing over a week ago, and orioles and Rose-breasted Grosbeaks are delighting the eyes and ears of many alert Northlanders.

Of all the spring migrants, one I look forward to every year is the White-crowned Sparrow. This sparrow is closely related to the White-throated Sparrow, but is slightly larger, its head seems smaller and flatter, and the dominant color of adults is a pearl gray compared to the browner white-throat. Both species have black and white striping on the crown, but the patterns are slightly different. And white-crowns are less likely to be found in the middle of dense woodlands and forests–they prefer edges of fields and meadows. Both species come to feeders, but usually white-throats outnumber white-crowns here in the Northland.

The White-crowned Sparrow’s song begins with a short whistled phrase like the white-throat, but ends up in a pretty, buzzy jumble.

(Recording of a White-crowned Sparrow)

The White-crowned Sparrow is one of the most studied birds in the country. In California, where a few races of this species live together, scientists have poked and prodded and studied caged birds to make several interesting discoveries. In one study, scientists in San Jose trapped and banded 574 White- crowned Sparrows and shipped them to the Patuxent Wildlife Research Center all the way across the country in Maryland, where they were released. The following fall, the scientists managed to retrap 8 of the birds, all the way back in San Jose.

Scientists have also studied regional dialects in White- crowned Sparrows. They’ve learned that the young sparrows learn their dialects from their parents during a sensitive period when they are 10 to 100 days old. When a young bird is taken from its parents and raised in isolation or with other young sparrows from the beginning of this period, it will develop a song different from the local dialect. But if the bird remains with its parents for just a few weeks, through the nesting period, its dialect will remain strong for life–even if it spends the rest of its days in a cage with birds singing a different tune.

Scientists have also measured the fatty deposits in White- crowned Sparrows to learn that the starting date of springtime fattening is very precise–this indicates that either day length or an innate clock triggers the body to start acquiring fat for migration. And scientists have studied orientation in these birds, too. In one study, the sparrows were placed in a round outdoor cage under an open California sky with electronic sensors on all the perches. In one nine day period between April 23 and May 1, one male oriented at random by day, but was completely different at night. He chose the perch on the N side of the cage 5299 times–that was 73% of the time. He sat on the NE perch 1053 times–15% of the time–and on the NW perch 411 times–6% of the time. He chose the other perches each less than 2% of the time. Even without an understanding of statistics, it’s clear that that was one bird that knew which way he wanted to go.

The White-crowned Sparrow winters in the southern United States, especially in the southwest. It breeds in alpine habitat, all the way up in northern Canada and high in the mountains in the western states. It’s just passing through the Northland right now, and won’t be around long, so check it out while it’s still here.

(Recording of a White-crowned Sparrow)

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