Birding and Feeder Comments

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My Sunday (Jan. 30) birding excursion followed the same route as last Tuesday, and the results were similar, with a few pleasant exceptions. Ice now extends several miles offshore, but large pools of open water break up the monotony. From fall to spring, Bald Eagles regularly hunt the large rafts of foraging waterfowl. Before the ice forms, they expend considerable energy flapping, as their quarry typically remains a couple miles offshore. Now, they simply perch on the ice and occasionally peruse the duck flocks with a leisurely fly-by. The best counts of Long-tailed Ducks can be obtained when eagles force an entire raft from one open lead to another. Plus, with the diminishment of open water, the Long-tails are clustering more. Today's count, 4750, was my highest so far this winter. Their numbers have been consistently down along Muskegon this year. Other ducks, especially Red-breasted Mergansers, are also less numerous than last winter. A flock of 95 Snow Buntings at Muskegon State Park was my highest total so far this year.

The best bird at White Lake Channel was a female Black Scoter, seen by Kathryn Mork and me. At Muskegon Lake Nature Preserve, Carol Cooper and I found two male Red-winged Blackbirds. These individuals, unbanded old males, were the first since November 28. Carol and Lois's diligence at keeping the feeders filled have now produced at least five out-of-season species there.

Evidence that the feeders are aiding the survival of certain birds is evinced by a particular Downy Woodpecker. On November 18, I banded a male Downy whose leg did not seem to grasp well. I noted it as a possible dislocation, processed it anyway, and released it. The leg injury was verified by subsequent observations (assuming it was the same bird), as it some difficulty clinging to some vertical trunks. Since leg injuries in woodpeckers are rare, I wondered about its survival. Fortunately, that individual is still making the rounds at the station, but it is still favoring one leg over another.

No doubt however, the impact of feeders cuts both ways. Outside my home in Norton Shores, where almost every backyard in the neighborhood has bird feeders, I have been seeing "sick" birds. Such signs include eyes that are not fully open, fluffing, extended stays at a feeder, sluggishness, orientation with the wind, late departures, separation from cohorts, and in extreme cases ignorance of predators, obvious listlessness, head bobbing, gaping or coughing, and weak flights. Problems had been restricted to House Sparrows. When I noticed a Tufted Titmouse that was feeding at my feeder (something very atypical for a Chickadee or Titmouse), I knew I had a problem. I opened a net and caught it. While the bird was not particularly light (90% of average mass, probably due to a very full gizzard), it had minimal fat deposits and only 25% of maximal flight muscle bulk. After release, it continued to feed in the same fashion for the rest of the day, and I have not seen it since.

I have encountered problems at feeders whenever House Sparrow densities (and to a lesser extent House Finches) get high. Consequently, I discourage the use of millet, which House Sparrows seem to prefer (though they do eat sunflower seeds). Millet is also more likely to fall to the ground, which is harder to keep sanitary than a feeder. Because most non-birders prefer to use millet and may be less diligent with keeping the feeders clean, feeding can often be a break-even proposition. Increased survival due to food availability may be offset by increased predation and disease transmission. Trying to reduce the spread of diseases by cutting the flow of seed at healthy feeders (thereby reducing aggregations and forcing birds revert to natural foods) may even exacerbate the situation, since most birds will simply move to other feeders in the neighborhood (often less sanitary ones). Practices that do help include regular feeder cleaning, keeping fairly small rations of food in a feeder (which discourages feces accumulation and encourages cleaning), discouraging squirrels (which spill lots of seed, especially millet) and maintaining a fresh supply of water for drinking and bathing.

Brian Johnson
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