Saturday, March 13, 2010

Birds

On my almost daily 4 mile walk up Bald Hill Road and back again, I regularly see or hear a handful of birds. White-breasted nuthatches, downy woodpeckers, American goldfinches, tufted titmice, and increasingly cardinals and red-bellied woodpeckers, are the most common. This fits with the trends just released in a new report -- The State of New Hampshire's Birds.

Pam Hunt of New Hampshire Audubon did an exhaustive review of the population trends of the 186 species of birds that breed in the state. The trends are a mixed bag. Sixty-nine species are increasing or stable. These tend to be birds that live here year-round or migrate a short distance, only as far as the southern U.S. This batch includes the six birds that I see regularly on my Bald Hill walk, since I see them year-round.

Another 65 breeders are declining. These birds typically migrate long distances to Central and South America or the Caribbean. Many are ground nesters, or feed on the wing for insects, or require large areas of forest. Many nest in grassy fields or shrub thickets. The balance of the breeding birds -- 52 species -- have uncertain or unknown population trends.

Overall, about one-third are doing okay, one-third are declining, and for a bit less than one-third of the species we don't know enough to say. Here is a table from the Report showing bird trends by habitat type.


A lot of birds that require shrubs are declining. These are birds that did well after farms were abandoned in the late 1800s. Abandoned pastures, row crops, and hayfields were left fallow and over a decade or more became "old fields," grown in with shrubs and small trees. By the mid 1990s, many of these old fields had succeeded to forest or were developed into houses, roads, or commercial sites, with the trend continuing to present time. As a result we are seeing fewer cuckoos, nighthawks, whip-poor-wills, kingbirds, catbirds, mockingbirds, field and song sparrows, house wrens, woodcock and grouse, among others. Only a few shrub birds are increasing or stable: American goldfinch, cardinal, willow flycatcher, and indigo bunting.

I was curious what other birds that I see regularly around my yard or on my walks are showing population increases. The report shows that these "regular birds of mine" are doing okay: wild turkey, turkey vulture, Cooper's hawk, pileated woodpecker, crow and raven, eastern bluebird, mourning dove, and pine warbler. I was surprised to read that blue jay, northern flicker, Baltimore oriole, scarlet tanager, veery, grackle, and dark-eyed junco are in decline.

The causes for bird declines are varied and sometimes unknown. Loss of habitat to development, natural changes in habitat, pesticides, predators, high levels of mercury, acid rain, excessive logging, and a raft of other issues could be affecting birds. There is no one cause. Birds that travel thousands of miles to avoid winter here, face multiple pressures as they fly to and fro. These birds will be arriving soon. I'll be paying more attention this year, to see who is up and who is down.

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