Some others have also described the method of feeding the young by regurgitation in a manner that differs from that observed by Miss Sherman. Mr. Brewster (1936), for example, says:
Standing on the edge of the hole, the parent would select one—usually the nearest, I thought—and bending down would drive his bill to its base into the gaping mouth which instantly closed tightly around it, when the head and bill of the parent was worked up and down with great rapidity for from one to one and one-half seconds (timed with a stop watch), the young meanwhile holding on desperately and apparently never once losing its grasp, although its poor little head was jerked up and down violently. The first, or entering downward thrust of the parent’s bill looked like a vicious stab, the bird apparently striking with all its force and as if with the design of piercing his offspring to the vitals. The subsequent up and down motion was invariably rapid and regular and resembled the bill movement of a woodpecker while “drumming.” It also suggested the stroke of a piston.
In this case the top of the stump had been broken off, leaving the nest open and exposed, so that every motion could be clearly seen from a distance of not over 15 feet. After the young had left the nest, he discovered that “the nest was left in a terribly foul state, the bottom being a disgusting mass of muddy excrement alive with wriggling worms. * * * These young, however, managed to keep very clean and all, so far as I could discover, were perfectly free from vermin.” Apparently the old birds find it difficult to clean the nest after the young reach a certain size.
W. I. Lyon (1922) tells an interesting story of a screech owl that adopted and brooded a family of young flickers, after its own nest in the same tree had been broken up twice; the owl even brought in part of a small bird, perhaps intending to feed it to the young flickers, which were all the time being fed by their parents and were successfully raised.
Plumages.—Miss Sherman (1910) gives a very good description of the naked and blind nestling, as follows: “The pellucid color of the newly hatched Flicker resembles that of freshly sun-burned human skin, but so translucent is the nestling’s skin that immediately after a feeding one can see the line of ants that stretches down the bird’s throat and remains in view two or three minutes before passing onward. This may be witnessed for several days while the skin assumes a coarser red, until it begins to thicken and become a bluish hue, before the appearance of the pin-feathers. These may be detected under the skin on the fifth day at the same time that bristle-like projections about one-sixteenth of an inch long announce the coming of the rectrices and remiges.”
Mr. Burns (1900) says: “It is not known when the white membranous process which extends from either side of the base of the lower mandible disappears, but it probably goes at a very early age. This formation is apparently peculiar to all young woodpeckers, as suggested by Frank A. Bates, in the Ornithologist and Oologist, Vol. XVI, p. 35, but its use is unknown.” A photograph, published by E. H. Forbush (1927), shows that this does not wholly disappear until the young bird is nearly fledged; its function is probably to help guide the regurgitated food from the mouth of the adult into the throat of the young bird during the feeding method noted by Miss Sherman (1910).
The young flicker is fully fledged in its juvenal plumage when it leaves the nest; and, contrary to the rule among birds, this plumage more nearly resembles the plumage of the adult male than that of the old female, as the young of both sexes have the black malar patches. The black bands on the upper parts are much broader, the vinaceous portions of the head and neck are more tinged with gray, the malar patches are duller black, and the lower parts are paler with duller and larger black spots than in the adult. The crown is usually more or less suffused with dull red, especially in young males, and sometimes the red nuchal crescent is somewhat wider or more extensive; the crescent on the breast is usually smaller; the yellow on the under sides of the wings and tail is duller and more greenish; the black tips in the tail are duller and not so sharply defined against the yellow; and the upper tail coverts are black with white spots, instead of being white and boldly barred with black, as in the adult. The plumage is soft and loose in texture and the bill is small and weak.
This plumage is worn but a short time, as a complete molt begins in July and is usually finished in September or October, producing a first winter plumage that is practically adult. Adults have a complete postnuptial molt at about the same time of year. A detailed account of the progress of the molt of young birds is given by William Palmer (1901) and one of the adults by Burns (1900); both accounts are too long to be quoted here. Fall adults in fresh plumage are very handsome birds, more deeply and richly colored than spring birds; the upper parts are deeper brown and the lower parts are suffused with yellowish buff; wear and fading produce a more contrasted plumage in the spring in which the dark markings are less obscured and the soft suffusion has disappeared.
The interesting and extensive hybridizing with the red-shafted flicker will be discussed under the latter species.
Food.—The flicker is more terrestrial in its feeding habits than any of our other woodpeckers. It is a common sight to see one of them hopping about on a lawn, or in an open place in the woods and fields, probing in the ground for ants or picking up ground insects or fallen berries. It is one of our most useful birds, worthy of the fullest protection. Professor Beal (1911) has shown that 60.92 percent of its food consists of animal matter and 39.08 percent of vegetable matter. About 75 percent of the animal food, or 45 percent of the entire food, consists of ants. The flicker eats more ants than any other bird; ants were found in 524 of the 684 stomachs examined, and 98 stomachs contained no other food; one stomach contained over 5,000 ants, and two others held over 3,000 each. If it had no other beneficial habit, the flicker would deserve protection for the good it does in keeping in check these injurious and annoying insects. Ants protect plant lice of various species, which may become very injurious to many kinds of cultivated plants, inflicting serious losses for the agricultural interests; the plant lice, or aphids, secrete a sweet honey-dew juice, of which the ants are very fond; consequently these tiny insects are herded by the ants and milked like cows. The ants take good care of their honey-producing “cattle,” driving them away from ladybugs and other enemies, leading them to new pastures, if the old ones dry up, sheltering the aphid eggs in their nests, and carrying the young aphids out onto the plants to feed. Mr. Forbush (1927) also says: “Ants riddle posts set in the ground or any timber or lumber resting upon or in contact with the ground. They destroy the sills of buildings set close to the ground and often ruin living trees, especially such as have a few dead roots. They infest lawns and buildings, destroying grass on the lawns and food in the house, and are difficult to eradicate. They sometimes eat alive the young of certain ground-nesting birds. They are very prolific and require a severe check on their numbers. Otherwise they would become unbearable pests.”