Every winter I get letters from readers asking why they are seeing fewer birds at their feeders.
"I am disappointed by the lack of cardinals and blue jays this year," writes Sheryll Jameson. "Do you have an explanation?"
"We have noticed very few blue jays recently," worries Frank Abruzzino. "Is there a reason?"
Answering such questions with confidence is difficult because many factors could be responsible. Maybe it's just a matter of using a cheaper, poor quality bird seed mix. Or maybe a new neighbor is offering more attractive food such as sunflower kernels, nuts and suet.
The most likely explanation for fluctuations in wild bird populations is that it's normal variation. Bird numbers rise and fall from year to year due to factors such as nesting success, predator abundance, weather, changes in habitat quality and increased road traffic.
Winter weather has a major effect on activities at bird feeders. Cold, snowy conditions invariably increase visits to feeders. Last week's record cold spell brought more birds to my feeders than I've seen in months.
Furthermore, unless numbers of birds are somehow measured every year, it's difficult to accurately detect population changes. For example, there may have been a few cold snowy days last winter when two dozen cardinals visited the feeders, and that's what's remembered and compared to this year.
Sometimes habitat changes cause bird numbers to increase or decrease. Recent activity by the natural gas industry in parts of Pennsylvania, Ohio and West Virginia has wreaked havoc on the landscape. Well pads and spider webs of pipelines riddle the countryside. And the truck traffic that accompanies these activities certainly takes a toll.
To get a wider perspective on this yvvear's winter bird populations, I checked with Emma Grieg, director of Project FeederWatch at the Cornell Lab of Ornithology.
"So far this year there's nothing to suggest any widespread problem with winter birds," she said. "And though we also get letters about fewer birds in some places, it's no more this year than other years."
Biologist, author, and broadcaster Scott Shalaway can be heard 8 to 10 a.m. Saturdays on 1370 WVLY-AM (Wheeling) or online at www.wvly.net. Contact him at www.drshalaway.com, firstname.lastname@example.org or 2222 Fish Ridge Road, Cameron, WV 26033.