October also brought our first robins and cedar waxwings. In spite of the large number of berried shrubs on our property, cotoneaster, toyon, eugenia and pyracantha, we have never had huge flocks of robins such as I’ve seen in nearby areas. That winter we were hosts to a pair of robins, one of whom, after Big Boy Blue was lured around to the front of the house with peanuts, tried repeatedly to take over the ledge. He didn’t succeed. Short-tempered and peremptory as he was, he lacked Big Boy’s substantial voice and personal force and as soon as be began driving the birds off one end of the ledge, they began congregating at the other end. Perhaps the explanation is simply that birds recognize members of the jay family as their enemies. For all his pomposity the robin is a thrush, no stealer of eggs or eater of nestlings, and he was more of a nuisance than a threat to the other birds.
The arrival of the waxwings presented an entirely different problem. These inoffensive little creatures, gentle as silk, were responsible for more havoc among the other birds than the robins and jays combined. The trouble was caused by their numbers and their gregarious instincts. One waxwing on a birdbath or a food perch still leaves plenty of room for a purple finch, a slaty fox sparrow, a brown towhee and a couple of Audubon warblers. In the world of birds, however, a single waxwing is very rare and seen only at the beginning of the fall season when one is scouting an area in advance, or at the beginning of the spring season when a crippled or diseased bird is left behind by the departing flock.
A hundred waxwings on a ledge, fifty in a birdbath, ten on a doughnut, will drive non-waxwings away more effectively than the tactics of birds twice the size and a dozen times more aggressive. What it boils down to is a matter of room. When there is no more room, other species of birds will simply depart, but the waxwings keep on coming even if they have to land on each other’s backs. Instinct tells them to follow their leader and follow they must, usually with good results but often with disastrous ones. We have had a dozen strike a window in as many seconds, most of them fatally, this in spite of the fact that I was standing at the window, waving them away with a newspaper.
Many similar events have made me a reluctant student of window kills — which of the dozens of species around our house actually hit the windows; what birds are killed, what ones are knocked out but survive, and what ones are tough enough to fly away uninjured, at least in any obvious way, and which birds are repeaters who have impaired faculties from previous strikes or other accidents.
The species that fits every one of the above categories and has more strikes to its discredit than all the others combined, including the waxwings, is the mourning dove. Doves also account for the most fatalities, though the percentage of these is low compared to the great number of strikes. It is a simple matter to keep track of the number because birds of this family have a grey powdery coating on their feathers which adheres to any surface they touch. If a window of our house goes unwashed for a month it becomes a showcase for a parade of glaucous ghosts. More than a dozen outlines of doves can be counted, each as clear as a photocopy. Band-tailed pigeons rank second in number of strikes but do not leave such complete or such distinct impressions on the glass, only half a wing sketched here or a bit of head there.
On any day in winter the mourning doves and band-tailed pigeons make up about ten percent of the birds feeding on our ledge. When ten percent of the population is responsible for over ninety percent of the window strikes we must be concerned with the reason why. All birds are believed to have superb eyesight. Experiments with pigeons have shown that they can differentiate as many as twenty shades of color, and since their eyes are at the sides of their heads, they have a field of vision of about 340°; in other words, they can see everything in their environment except the space occupied by their own bodies (Welty, The Life of Birds). In spite of all this I’m tempted to think that members of this family have some organic or functional weakness of the eye. (Perhaps I should explain at this point that the lighting in our front room is arranged so that no bird can mistake it for a fly through: when the north window is open, the south one is draped, and so on.)
A few of the less serious window strikes involving pigeons and doves may be accounted for by their awkwardness in handling themselves at close quarters, landing or taking off. Most of the fatalities, however, occur when a bird, starting in another part of the canyon, comes at full speed toward our windows in what appears to be nothing less than a suicide attempt. For some time we preserved on glass an example of this kind of strike. It happened in the fall of 1964. While talking to a friend on the telephone I saw a mourning dove fly out from the top of a eucalyptus tree about two hundred feet away. The bird’s flight was very fast and very direct, straight toward our window. It hit head on, its wings raised for the next beat that never came. The sound of the impact was so loud that my friend on the other end of the telephone thought it was some kind of explosion. Certainly death must have been instantaneous, for the dove ricocheted into the heavy underbrush on the canyon slope, leaving behind on the window a perfect record of the last episode in its life.
Of the ghosts on our glass this one was the clearest: feather and foot, head, beak and eyes — in fact, the outlines of its eyes, we discovered, were not outlines at all but the actual eyes themselves which had been jolted out of their sockets and adhered to the glass like glue. For several months we left that part of the window unwashed and while the eyes very gradually shrank in size, the rest of the dove’s memorial remained unfaded by sun, unerased by rain and fog.
The speed of the bird’s flight indicated that it was attempting to escape man or hawk. But it had other and safer directions to take, and plenty of time to alter course. Why did this dove, and many others before and after it, fly directly to their deaths when a lift of just a few feet would have allowed them to clear both the window and the roof?
Hermit thrushes and fox sparrows were responsible for a much greater percentage of window strikes than their small numbers would lead us to expect. Conversely, some species struck rarely or not at all. For seven months of every year there were as many Audubon warblers feeding on our ledge as there were house finches. It might reasonably be assumed that the finches, who spent their entire lives around buildings, would be sophisticated about windows, and that the tree-dwelling warblers would not. The opposite turned out to be true. One Audubon warbler, an immature, died in this manner compared to dozens of house finches. In the winter of 1964–1965 we had seven kinds of sparrows at the feeding station — Lincoln’s, song, golden-crowned, white-crowned, Harris’, English and fox — and only the last named ever struck any of our windows. The record of the icterid family is even better: no strikes among the hundreds of cowbirds, red-winged and tricolor blackbirds, hooded and Bullock orioles. Jays, woodpeckers, mockers and thrashers also have perfect records.