Nature Notes

By May, we don’t need signs of spring, but if we did, the trill of a chipping would certainly be one. These little brown sparrows with a rusty red cap arrive here from southern wintering grounds from mid-March through May and get busy pairing up and nesting. They like open areas with trees and shrubs, so they often show up in our yards, towns, fields, gardens, and parks. The trill that you might hear in your neighborhood is a male’s way of proclaiming a territory and attracting a female (Songs).

You might spot a pair of chipping sparrows sparrow (Spizella passerina) moving around your yard, coming to a bird feeder for seeds, or hopping on the ground. Male and female look alike. That’s a clue that both share the work of nesting and raising young, although they don’t always do the same chores. You might notice them gathering nesting material. Often the male follows the female around as she picks up dry grasses, fine rootlets, and even animal hair, such as horse hair. Most likely, the male is guarding her from other potential mates.

The female typically builds the cup nest. If you watch the comings and goings of a pair, you might spot its location. It’s typically low, 3-10 feet high in a shrub or tree. Chipping sparrows like evergreens, including ornamental ones planted in yards. The female first builds the rim of the nest on an upright fork of branches, and then the cup which hangs from the rim. The softest materials, such as hair, get added last, as lining. Building takes about 4 days.

Chipping sparrows typically lay four blue-green eggs, one per day. The female develops a brood patch. It’s a featherless area of bare skin on the belly. It helps her to warm eggs and newly hatched chicks. While the female incubates, the male forages and brings food to her. At this time of year, insects are a key source of protein, for both the female and growing chicks. Chipping sparrows go for the various life stages of moths and butterflies, such as caterpillars, cocoons, and chrysalises, as well as beetles, grasshoppers, and crickets. Remember that we need insects because birds need them.

You might be surprised how quickly things move along. Incubation typically lasts 10-12 days. Chipping sparrow chicks hatch naked and with eyes closed. On their 2nd day, feathers start to grow in. The chicks’ eyes open fully by their 7th day. By the 10th day, the chicks are mostly feathered. You might hear the chicks peeping as they beg for food.

The chicks typically leave the nest when they are only 9-12 days old and almost adult size. They don’t just fly away. Instead, they get on the rim of the nest and then move to nearby branches. They fly short distances for about three days. The parent birds continue to feed them. The chicks remain dependent for about 3 weeks while learning to find food. During this time, the female may start a new nest, while the male tends the chicks.

Why build a new nest? A big reason may be that predators, such as snakes, crows, blue jays, squirrels, and cats, might have learned the location of the first nest due to all the noise and activity around it. Another reason may be that the first nest often gets infested with parasites such as lice and mites.

Around mid-July, chipping sparrow nesting winds down. Parents and young switch from family life to flock life. It’s time to prepare for migration, so finding food is serious business. Chipping sparrows like crabgrass seeds, among others.

You’ll hear much less trilling now. Instead, you might notice a lot of the single “chip” calls that give these sparrows their name. Their chip calls are a way of communicating among themselves. Young chipping sparrows may gather together in flocks. The parents may separate and join flocks of other adults, sometimes mixed flocks containing other small songbirds.

Fall is another good time to see and hear chipping sparrows. Their numbers usually peak in October as flocks migrate through our region, with both local chipping sparrows and those from farther north. Look for them in fields, on the ground, and at feeders filled with seeds.

What about next year? Will the same pair come back and do it all again? In general, migration is a hazardous business. For small songbirds such as chipping sparrows, each bird has a 50-50 chance of surviving to return. In other words, survival is a coin toss for each bird. That amounts to only a 25 percent chance (1 in 4) of both birds reappearing next year. The odds are a little better that one will return but will need a new mate.

How do you tell a chipping sparrow from all the other sparrows that frequent our region? Near houses and other human structures, house sparrows (Passer domesticus) are common. Notice that they’re chunky, nest in colonies, live here year-round, and look and sound different with their “cheep” sounds.

The trill is a way to recognize chipping sparrows. It’s either fast or slow, but made up of a single note repeated many times. It’s often described as sounding “dry” (not musical) and mechanical, almost like an insect song.

You may hear other trills. Walking in pine woods in spring, you might find the pine warbler’s (Setophaga pinus) song somewhat similar, but a bit more musical. Also in spring, the junco’s (Junco hyemalis) spring song might sound similar. Near a swamp, you might hear a swamp sparrow’s song (Melospiza georgiana). It’s all on one note but slower and “liquid.” In fields, the trill of a field sparrow (Spizella pusilla) starts slowly and noticeably speeds up as it rises in pitch.

How can birds tell the differences among trills that seem pretty similar to us? It’s easier for birds to do, because they process sound more than twice as fast as humans do. Differences are easier for them to notice. How’s that for a “bird brain”?

What about telling chipping sparrows apart from other sparrows by looks? Also easier said than done. A rusty red cap on the head is a good clue that a sparrow-like bird might be s a chipping sparrow, but at least three other sparrows in our region also have rusty red caps. And again, birds see better than we do in certain ways. They process visual information faster than humans do – something that’s helpful for flying and for tracking movements of insect prey and potential predators such as hawks.

What else might you notice about the appearance of chipping sparrows and other rusty-capped sparrows to distinguish them from one another? A swamp sparrow has a rusty cap but a white throat. A field sparrow has a distinctive pink bill (easier to notice with binoculars). An American tree sparrow, found around here in late summer or fall, has a single black mark on its clear breast.

Of course, there are even more sparrows, but many of them, such as song sparrows, have heavy streaking, no rusty cap, and more complex songs (song).

Enjoy listening and watching for sparrows. Happy spring!