Birds of Indian Subcontinent

Comparative Notes on the Life History of the Carolina Chickadee

Publication Type:Journal Article
Year of Publication:1961
Authors:Brewer, R
Journal:The Wilson Bulletin
Date Published:1961
ISBN Number:00435643
Keywords:Dryobates pubescens, Parus, Parus atricapillus, Parus carolinensis, Picoides pubescens, Poecile, Poecile atricapilla, Poecile atricapillus, Poecile carolinensis, Regulus, Regulus satrapa, Satrapa, Sitta, Sitta carolinensis, Sitta europaea, Sittidae
Abstract:The life history of the Carolina Chickadee was studied from October 1954 to November 1959. During the same period observations were made on Black-capped Chickadees and a population believed to be composed at least partly of hybrid birds. Most of the field work was in Illinois, with that for the presumed hybrid population confined mainly to the contact zone near Vandalia. The three populations were found to be similar or identical in most respects. In winter, chickadees of all three populations tend to occur in flocks, the mean size of which is three to four birds in Illinois. Home range size appears to be related to food supply and is on the order of 35 acres at the latitude of central Illinois. Chickadee flocks tend to occur in temporary feeding parties. In spring and fall these parties may include migrant warblers and vireos; in winter, the most frequent associates of chickadees are Tufted Titmice, Downy Woodpeckers, Golden-crowned Kinglets, and White-breasted Nuthatches. Pair formation apparently begins in the flock and is a gradual process. Members of a nesting pair tend to remain together during the winter and, if both survive, to nest together the following season. Excavation and even nest-building may be begun at several locations before the pair finally concentrates on the site which is actually used. Carolina and Black-capped Chickadees almost invariably excavate their own cavity, with both sexes participating. In the Vandalia population, excavation appeared nearly confined to the female. Nests in Illinois are usually of moss overlain by fine bark strips and lined with fur. Gathering of nesting materials and nest building is almost entirely by the female. Eggs are laid one each day in the morning. A geographical trend in clutch size exists, with Carolina Chickadees tending to have larger clutches at any given latitude than Black-capped Chickadees. Date of laying of first egg also varies geographically, tending to be 3½-4½ days later for each degree of latitude northward. Incubation is by the female and is begun with laying of the last or next to last egg. The incubation period appears to be about 13 days. Attentiveness is about 75 per cent for the Carolina and Black-capped Chickadees. Attentive periods in Illinois average about 15-20 minutes in length, inattentive periods 5-8. In the two species, the incubating female is fed by the male about two to three times per hour of attentiveness. During inattentive periods the female gives a begging display and is fed repeatedly by the male. Among apparent abnormalities observed in the Vandalia population were a nearly complete lack of on-the-nest feedings of the female by the male, initiation of incubation with the laying of the first or second egg (in one pair), and a low rate of hatching and fledging of young. Hatching of the complete clutch in all three populations requires about 12-24 hours. The percentage of time spent brooding is about the same as that spent incubating for the first three days after hatching; then there is a rapid decline until brooding is completely discontinued about the 11th day. At first, feeding of nestlings is almost entirely by the male, but by the end of nest life, the female has assumed the greater share of this duty. Length of nest life is about 16 days. Development of young Carolina and Black-capped Chickadees studied in the laboratory from the 13th day on seemed essentially identical, as did the behavior of fledglings during the first 10 days after leaving the nest. By about 7 days after leaving the nest, young are able to forage for themselves to some degree, but may remain with the parents for another two weeks before the family group breaks up. The two species have an extensive and similar vocabulary. Small differences exist in the whistled song, the signal song, and to some degree the general call note. Many birds of the Vandalia population gave whistled songs and signal songs far outside the normal range of variation of the two parental species. Miscellaneous activities, such as preening, bathing, and sun-bathing, appear to be similar or identical in the three populations. The pattern of daily activity is similar, with awakening time related fairly closely to sunrise in the female. The male tends to arise earlier and retire later than the female in the breeding season. Within each species, weight varies with latitude, sex, season, and time of day. With other conditions equal, Carolina Chickadees appear to weigh slightly less than do Black-capped Chickadees.
Short Title:The Wilson Bulletin
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