LATE LAST SPRING, I spent about 15 hours over a three-day period sitting in a Monroe County back yard watching a bird feeding station.
Coming and going to and from the feeders were cardinals and house finches, downy woodpeckers and chickadees, chipping sparrows and even an indigo bunting. A chipmunk joined grackles, red-winged blackbirds, mourning doves and house sparrows below the feeding trays. In the recently mown field beyond the lawn, yellow and chestnut-sided warblers searched the grass for seeds and insects.
But I never saw what I was looking for. I was watching for a chipping sparrow with two heads.
I had learned of this remarkable possibility from an Internet bird chat line. The message called attention to the report, gave the address and added, "I question this but it might be worth checking out."
Despite that disclaimer, I phoned the Hilton couple, Bob and Grace Carson, to ask about their sighting. Yes, they had seen the bird several times and had photographed it through their kitchen window.
They were afraid, however, that even taken with a telephoto lens the pictures would not be definitive. Would I come to confirm their observation? I went -- I watched -- but I failed to see the bird.
A two-headed bird would be the wildlife equivalent of conjoined human twins and would be at least as rare.
Bird abnormalities have been reported, of course. A 1934 study of 100,000 starlings, for example, turned up more than 5 percent with various deformities, but they were things like malformed bills, unusual size or missing eyes, legs, feet or toenails.
Other observers have noted wild birds with extra pairs of legs or wings -- a phenomenon called duplicity that is also found occasionally in domestic fowl. But I turned up no record of a two-headed bird.
I, however, did come across an interesting and detailed description of a two-headed black rat snake. The ethologists who studied the snake called it IM, the letters representing instinct and mind. Gordon Burghart writes, "The snake's frequent conflicts over prey, usually mice, vividly reminded me of the perennial conflict between those two concepts. . . . Regardless of whether one or both heads struck, both heads often simultaneously attempted to swallow the prey."
The Carsons described their sparrow as having the second head facing backwards, the bills pointing in opposite directions. Grace told me how it twisted so that each head could feed in turn. Unfortunately, Bob's later reports indicated that the second head became inactive and drooped lifeless down the bird's back.
I never saw any of this, although I missed one reported appearance by only 10 minutes. I did see a few feathers on one bird's nape raised by the breeze, and I tried to convince myself that was what the Carsons were seeing.
But now finally the photographs have been printed, and Bob has forwarded copies. Although none are ideal, I believe that they confirm the Carsons' observations of this bizarre anomaly. The best shows the bird perched opposite a house finch at a tube feeder, its body facing away from us, one head turned to the left, the other to the right.
The left head is fully plumaged with the red cap of an adult chippy, the right retaining the characteristics of an immature bird. In two photos taken later, that immature plumaged head has lost its vitality and lies lifeless against its back.
After a week of those late May visits, the bird failed to return.
By now, it almost certainly has died, but its brief appearance at the Carson feeder represents an extraordinary ornithological first.