By Connie Mertz
For The Daily Item
For 112 years, the National Audubon Society has conducted an annual Christmas Bird Count making it the longest running citizen-science survey group in the world. Thousands of volunteers across North America brave winter's weather for one day, starting in the pre-dawn hours, to compile bird sightings.
"The data collected from the CBC allows researchers, conservation biologists and other interested individuals to study the long-term health and status of bird populations across North America. When combined with other surveys, such as the Breeding Bird Survey, it provides a picture of how the continent's bird populations have changed in time and space over the past hundred years," stated Dan Brauning, Pennsylvania Game Commission Wildlife Diversity Division chief.
One of the CBC's count circles is Bloomsburg, which includes Montour Preserve.
"Our local count is just a drop in the bucket compared to the bigger picture of the northeast or even North America," Jon Beam, senior naturalist at the preserve, said. "However, the data does show population trends.
"The data indicates where unusual birds are showing up," noted Beam.
Gross also said that the annual data monitors wintering birds as well.
The warmer weather this fall allowed for more waterfowl sightings simply because Lake Chillisquaque was all open water.
"The mild weather has not pushed some birds south into Pennsylvania that often show up this time of year. Notable examples are rough-legged hawks, but the mild weather provided us with sightings of a goldeneye, hooded and common mergansers, ruddy ducks, and of course, black ducks, mallards and Canada geese," Beam added.
Once again two bald eagles were seen on Montour Preserve for the CBC, as well as double-crested cormorants.
While winter may seem an off-season to see bird species, there are advantages, according to Gross. With binoculars and guide books in hand, birds are easier to spot in leafless trees thus making it easier for the amateur bird watcher, including children.
"Birders learn more about habitat associations and the value of cover and food sources to birds, such as winterberry, rose hips and sumac," he said.
For the past several years, bluebirds have been sighted. "Some bluebirds still do migrate, but often males will tough out the winter here. They find egg masses, insect pupa and even adult insects on warmer days. Several bluebirds will roost together at night either in a natural cavity or a nest box to keep warm," Beam commented.
Even some robins remain rather than migrate. According to Beam they prefer woodlands where they feed on berries. Gross adds that usually bluebirds, hermit thrushes and robins are often spotted where wild fruits are located.
So what are the 10 most common wintering birds in Central Pennsylvania? Beam admits they can vary from year to year, but they are primarily Canada goose, European starling, mallard, mourning dove, downy woodpecker, black-capped chickadee, tufted titmouse, dark-eyed junco, Eastern bluebird and blue jay.
In decline are ruffed grouse and bobwhite quail, meadowlarks and other grass nesters, evening grosbeak, plus several others. Check out birds.audubon.org for a complete list of the bird species in decline.
n Connie Mertz is a nature enthusiast from Danville. Contact her at email@example.com.