Bird count assesses local bird populations

Special to the Gazette

Since September, readers have contacted me with one burning question. There has been a spirited discussion in the Last Word and much gnashing of teeth over the counters at our local bird feeding stores. I was even accosted while buying cheese at the supermarket recently. Everyone has the same concern. Their feeders are not being visited. Their birdseed is not being consumed. Where have all the birds gone?

My standard reply has been that it has just been a very warm autumn so there are still plenty of tasty native fruits and insects available. In fact, a version of this hysteria occurs every autumn, when the birdseed goes out before migrants arrive and the natural food runs out. Goldfinches, in particular, abandon their favorite summer feeders to feast on September’s banquet of dried flowers. Year after year, I have assured people that once cold weather arrives, the feeders would be bustling again. Usually, I am correct. But following our first cold snap, the emails kept coming. Is someone using a sonic weapon on the birds? Could it be the hawks? Does the area finally have too many houses and outdoor cats?

Rather than continue to issue tentative assurances based on intuition, I turn to the data from last week’s Christmas Bird Count, performed by more than 110 local birdwatchers on Dec. 17. This is an unbiased survey of the entire area, including dozens of feeder watchers and a thousand miles walked and driven through marsh and forest.

If birds have suddenly become scarce, the count should be below average, and we can start to uncover the causes by determining which species are missing. In fact, this year’s count had, drum roll please, the highest number of species ever, including over 100 Bald Eagles. But this list includes a good number of rare species such as black-crowned night-heron, Virginia rail, orange-crowned warbler and blue-headed vireo. Four rarities were even found by feeder-watchers: western tanager, ruby-throated hummingbird, painted bunting and seven Baltimore orioles at the same feeder. But rare species don’t tell us much about overall population health.

What about sheer numbers of common species, the ones people think are missing from their feeders? A total of 46,000 birds were counted, which is above average, but about 26,000 of these were blackbirds flying overhead to distant roosts.

Of the remaining 20,000 individual birds, I took a look at the counts of the most visible of our feeder denizens: Carolina chickadee, tufted titmouse, Carolina wren, eastern bluebird, dark-eyed junco, white-throated sparrow, northern cardinal and American goldfinch. Of these, six species had the lowest count in five years, and the remaining two had the second lowest counts. All of these species have steady or increasing population trends, locally and nationwide, so their sudden rarity this year demands an explanation.

The Williamsburg Christmas Bird Count bears out the astute observations of Virginia Gazette readers, that feeder birds are truly scarce this year. Is it the warm weather? Have we reached a tipping point of forest loss in the area? Is it pesticides in the birdseed? Please light up the Last Word with your explanations.

Cristol teaches in the Biology Department at the College of William and Mary and can be contacted at dacris@wm.edu. To discover local birding opportunities visit williamsburgbirdclub.org.

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