Photo: Ron Holmes
The White-crowned Sparrow is a common backyard bird in November. But which subspecies are you viewing? There are five subspecies. Two are attracted to Skagit County during different seasons. The influx of birds arriving under your fall feeders are the gambelii. The fairly common subspecies observed in summer is the pugetensis. For an expert "birder by ear," the song is a distinguishing field mark.
Their song is the most studied of all birds. Even within the five subspecies there are different dialects. Many ornithologists believe dialects are genetic adaptations for local conditions. However, when female birds were injected with male hormones to induce singing, the females sang songs using the dialects of males from nearby territories. Presumably, these were males they had mated with and therefore lead scientists to believe the dialects are learned behaviors and not habitat related.
These birds are very prolific breeders. They can produce three to four broods each year. In fact, the female only feeds her young for the first 3 to 4 days. She's off building a new nest for their next brood. The male is left feeding the first brood which fledges within 7 to 12 days. In migratory populations, the birds are polygynous.
The male can have several females within his territory at the same time. The females will divide and defend their area within his territory. Some females sing to defend their area from other females, which is behavior usually reserved for males only. Males arrive to breeding areas 2 to 3 weeks before females to establish territories. In nonmigratory populations, the birds are monogamous and pair for life.
Each cup nest is constructed with twigs, leaves, grass and shredded bark. A female may build up to three nests each season. She lays 2 to 6 light blue or green eggs with brown flecks. The female incubates the eggs which takes about two weeks. Nests are usually found in low bushes and trees. Occasionally, some are found on the ground in clumps of grass or moss.
A medium sized sparrow, adults are easily identified with black and white stripes on their heads. The color of their bills are regionally influenced and can range from pink to orange. Pacific Coast birds have yellow bills. Immature birds have the stripe pattern on their crowns but with cream and brown feathers. Similar sparrows include the White-throated Sparrow and the Golden-crowned Sparrow.
The White-throated Sparrow is a rare Northwest visitor. It has similar black and white strips on its crown, but has a gray bill and yellow spots between the bill and eye. The Golden-crowned Sparrow is a common winter visitor to Skagit County and is about the same size and can be found in similar habitats as the White-crowned Sparrow. It is distinguished by the yellow crown and wider black stripes.
To attract White-crowned Sparrows to your feeders, use sunflower or mixed seed. Place your feeder near bushes or a pile of sticks for cover. These birds will be observed foraging on the ground. On bird walks, look for them near bushes with berries. They can also be seen in leaf litter searching for seeds and insects.