Mind of the Raven: Investigations and Adventures With Wolf-Birds by Bernd Heinrich

reach their full adult weight of three to four pounds in about three or four weeks. What food of such vast bulk, I wondered, could the adults possibly find for their young at the time of year to which their breeding cycle is synchronized?
    Ravens, like us, are considered omnivores. Given a choice of foods, my captive adults will eat the cholesterol-rich and fatty kind: cheese, grasshoppers, salty peanuts, eggs, butter, potato chips, and hamburgers. Next on the list come mice, birds, deer and moose meat, blueberries, maggots, tomatoes, carrion beetles, fish, oatmeal, and corn. Only a limited selection of this fare is available in the Maine woods in May.
    Along the coast of Maine, a most important food for the island-nesting ravens during chick-feeding time is seabirds and their eggs. John Drury, an ornithologist from the island of Vinalhaven, Maine, told me that the ravens there can frequently be seen flying over and landing in raspberry patches where the eider ducks nest. The eider nests in those raspberry patches are soon without eggs, and the nests’ down is strewn around. Near one cliff nest of ravens on Seal Island, John found the shells of thirteen eider eggs, and the picked-over skeletons of thirteen black guillemots. The year before, there had been nine eider egg shells and remains of two guillemots at the same raven nest. At a raven nest site on Great Spoon Island, John found shells of eggs of six to seven herring gull, one or two black-backed gull, thirteen eider, two cormorant, plus heads of three gulls, four eiders, and parts of two unidentified bird vertebral columns. Two weeks later, he found eleven more eider egg shells, and the remains of two guillemots and one blackbird. By a raven nest in a spruce tree on Metinic Island, there was evidence of similar fare. In contrast, near Bowdoinham, also on the Maine coast, Tinker Vitelli has since 1988 observed a pair of ravens nesting in a pine grove, and there the young are fed mostly freshwater mussels from a nearby stream. The ravens bring the mussels in whole and carry the empty shells away, never leaving any under the nest tree.
    Inland, the Maine forest ravens face a different situation. I suspected these ravens’ survival and reproduction were linked to deer and moose. In the fall, ravens invariably show up where hunters leave theentrails of deer or moose. In the winter and early spring, ravens may rely on deer that are killed by the sometimes lethal and tightly interrelated combination of cold, deep snow, starvation, and coyotes. Perhaps the cold storage of winter allows food to accumulate so that ravens can nest before the meat decays in the spring.
    Maine has an area of 33, 265 square miles, and an annual prehunting season population of about 300,000 deer. In recent years, the annual reported deer kill during the hunting season is approximately 27,000 animals, and the moose kill is about 1,500. The Maine Department of Inland Fisheries and Wildlife estimates that as many animals are killed illegally as are killed legally. Added to the count are the carcasses of beavers, coyotes, and other animals that trappers leave in the woods. This leads to a conservative estimate of about two meat piles per square mile over the year, in addition to the carcasses left from natural die-off.
    In the winter of 1992-93, I had picked up fifty-nine raven pellets under roost trees where a vagrant crowd was sleeping nightly while feeding on the calves I had provided. Ten of these consisted mostly of deer hair, and five of mountain ash seeds (see Table 4.1). These findings only suggest what ravens feed on. They are not a reflection of how much . Eating only one berry would produce seeds in a pellet, but a raven might feed on the viscera of a deer for days and pick up only a few hairs.
    Deer carcasses apparently are available, although the plucking of fur off live animals cannot be precluded. Of the more than fifty nests I have examined, all have been lined with deer fur. The nest