The comings and goings of backyard birds

Written by Jack Sanders
Thursday, 15 December 2011 11:26

Frank McBrearity of New Canaan, who describes himself as “an amateur birdwatcher who has maintained easily watched birdfeeders in the rear yard for more than 20 years,” has been puzzled by observations since September.

“The deviations from the norm began in late September when the swarm of birds hovering around and near our feeders almost completely disappeared,” Frank said. “Some of the departures were expected, of course. The hummingbird family left for warmer climes during the week of Sept. 18. At about the same time, other summer birds departed. The flock of goldfinches left along with some annoying grackles. So did the ground feeders: robins, Gray Catbirds, doves, and the occasional flickers.

“But to our surprise, all the other birds left as well. All the regulars departed in late September: The clusters of chickadees, titmice, and nuthatches that would congregate in the nearby bushes awaiting an opening — all gone. The ever-present Blue Jays and cardinals, gone as well. The Carolina and House Wrens, which always seemed near the house, were suddenly absent — no cheerful songs to start the day. The woodpeckers that regularly fed at the feeders were suddenly absent as well.

“Most of these bird types could be easily seen elsewhere on any given day, but they were not feeding at our feeders. Was it something personal? Perhaps they heard me complaining about the rising cost of sunflower seed? It was odd, a new experience for our back yard. The column of birdseed that would drop precipitously over just a few days, stood almost stationary for many days at a time. An occasional chickadee or titmouse would grab a bite and fly away; no Blue Jays, no cardinals, no finches, no woodpeckers. What had happened?

“Then, around Thanksgiving, all the regulars returned: Blue Jays, cardinals, chickadees and titmice in significant numbers, nuthatches, woodpeckers, doves and some finches. The wrens are back around the house, hovering under the suet cake for easy pickings. A large number of sparrows are evident this year, and the juncos have returned for their winter visit.

“I can’t explain the two-month hiatus; it was quite unusual for us. But for now the pattern at the feeder is close to normal, although the presence of Blue Jays and cardinals seems much less than in previous years.”

Many factors can change what shows up in your yard, including:

• The neighborhood food supplies. Feeders are only a fraction of the food source for birds. A change in the natural food supply can make a lot of difference in local bird populations, which will quickly move elsewhere in search of good grub. For instance, Hurricane Irene may have changed the availability of some wild seeds and berries, and perhaps some kinds of insects.

• Neighborhood habitat. Changes in the places where birds nest, roost and feed can vary the population. For example, some birds like evergreens for roosting and nesting. If someone cut down, a storm felled, or disease killed a noticeable number of evergreens in the area, certain species might become less common. Again, perhaps Irene had a temporary effect here.

• Predator changes. A hawk or perhaps even an owl deciding to nest in the middle of an area popular with songbirds would discourage the songbirds from hanging around. Even something as seemingly innocuous as a family cat — and worse, feral cats — can affect the bird population in a small area. (The number of birds killed by pet cats each year would astound most people.)

• Man-made environmental changes. Obviously, major sources of noise, light, or air pollution can affect local bird populations. Set up a rock crusher next to a stand of trees that has sheltered birds for years, and you will undoubtedly chase them all away. But less obvious changes can occur. For example, spraying trees for caterpillars may kill many of the insects the birds feed on, forcing them to look elsewhere.

• Disease. Of course, disease can affect local and regional populations of birds. A few years ago, there were many reports of Pine Siskins dying, probably from Salmonellosis. West Nile virus, to which corvids seem susceptible, may be affecting the jay population.

Bird populations fluctuate naturally, mostly due to changes in food supplies. However, any change is of interest to ornithologists, and that’s why the Cornell Lab of Ornithology has set up programs like Project Feeder Watch, in which “citizen scientists” — you and I — regularly report what we see out our windows each cold-weather season to the professional scientists in Ithaca. To find out more about Project Feeder Watch, visit birds.cornell.edu/pfw/

Coming up

Family Bird Watching Class & “Christmas Bird Count” Practice, Saturday, Dec. 17, 1 to 2:30, $5, Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x230 greenwich.audubon.org.

Christmas Bird Count: all-day census of local birds, done by small regions; local counts include: Westport Bird Count, Sunday, Dec. 18, [Mardi and Townsend Dickinson, 203-846-0359, This e-mail address is being protected from spambots. You need JavaScript enabled to view it ]; Greenwich CBC Sunday, Dec. 18 [Brian O’Toole, This e-mail address is being protected from spambots. You need JavaScript enabled to view it or 203-869-5272 ext. 228); Peekskill CBC, Saturday, Dec. 17, [Mike Newhouse, This e-mail address is being protected from spambots. You need JavaScript enabled to view it ]; Putnam County CBC Friday, Dec. 30 [Charlie Roberto, This e-mail address is being protected from spambots. You need JavaScript enabled to view it or 845-270-2979]. For details about the CBC, visit http://birds.audubon.org/cbc.

Montauk Birding Overnight, Sunday, Jan. 15, evening to Monday, Jan. 16, evening, Saw Mill River Audubon, (914) 666-6503, This e-mail address is being protected from spambots. You need JavaScript enabled to view it , sawmillriveraudubon.org.

Eagle Viewing Trips, on Connecticut River, Feb. 11 through March 18, 9, 11:30 and 2 on weekends, and 10 and 1 on Thursdays, $40, Connecticut Audubon, 1-800-996-8747.

Cuba bird study, trip with Connecticut Audubon, survey work involved, March 3-15, 860-767-0660.

Copyright 2011 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] gmail.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.