A preliminary life history study of the Florida jay, Cyanocitta c. coerulescens. American Museum novitates ; no. 1252
Supplemental Materials
Date
1944
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New York City : The American Museum of Natural History
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Abstract
"The Florida jay (Cyanocitta c. coerulescens) was studied from March 27 to April 29 near Lake Placid, Florida. Though a short-winged species it takes many short flights and more rarely longer ones. Most of its time is spent in hopping in open areas or among the twigs of bushes in search of food or in perching. Unlike most bush-inhabiting species it is bold and becomes very tame. It buries food usually by thrusting it beneath the sand without digging a hole, but was once observed to drive a hard piece of food beneath the sand with blows of its bill. Leaves or other small objects are placed over the spot where food is buried. In searching for buried food the jay swings its head from side to side throwing the sand to either side with the bill. Hard objects are held in the feet and broken with the bill; often certain projecting roots or similar objects are habitually used for this purpose. Frustration or rage is expressed by striking on the perch with the bill and by screeching. The male is much more aggressive. Acorns presumably buried the preceding autumn were being consumed in numbers, but the bulk of the food was animal matter. Insects are captured both in bushes and on the ground, sometimes after spirited pursuits. A variety of calls, chiefly harsh, are given and also a peculiar, evidently mechanically produced 'hiccuping.' The latter is given usually, if not exclusively, by the female and serves as a threat to other jays and probably in other ways. A whisper song is given by both sexes and seems to express either physical well being or mild perplexity. Males in a courtship display were twice observed to hop, with head elevated and tail spread and dragging, around females. Both of these pairs practiced courtship feeding and presumably were in a pre-nest-building or at least pre-incubation period of the reproductive cycle. Courtship feeding is continued through incubation and to some extent after the young hatch. Both sexes participate in nest building, but there is a tendency for males to do less than females. One nest was completed in six days and another in four days, although a little was added to it on the fifth day. The former was a second nest, and the first egg was laid on the eighth day after it was begun. Nest-building attentive periods varied from 30 to over 158 minutes each and inattentive periods from 25 to 113 minutes. Inattentive periods were usually spent about one-third mile from the nest; the time was spent in feeding, resting, and preening, or squabbling with other jays; courtship feeding occurred at infrequent intervals. Nest-building periods comprised about three-fourths of the total (daylight) time. Only the female incubates. At a repeat nest the female spent most of the two-day period between the finishing of the nest and the laying of the first egg in perching or brooding on the nest. Incubation, or at least light brooding, starts with the first egg. The observed females spent about 80 or 90 per cent of their time incubating; attentive periods usually vary from 10 to 60 minutes but one of 106 was recorded; inattentive periods are usually of less than 5 minutes. One male usually fed his mate at the nest once or twice during each attentive period, but at another nest only one feeding was recorded. The male spends much time on a conspicuous perch near the nest, but is often absent from the nest vicinity; his behavior except when feeding his mate on the nest does not seem to be correlated with his mate's incubating rhythm to any great extent. Both sexes share in feeding the young, but the female alone broods. Young are fed two or three times an hour during the first week, and this gradually is increased to five to twelve by the second week. Up to the termination of observation when the oldest young were about fifteen days old, they were brooded more than half of the time, partly, it seemed, to protect them from the sun. At one nest the female fluttered her wings and begged when the male brought food. She usually received part of it, and both shared in feeding the young. After feeding, the parents wait for the appearance of fecal sacs; these are eaten or carried away. During all phases of the nesting cycle jays sometimes attack other jays which approach the vicinity of their nest. Stuffed jays and also a screech owl were attacked, but a stuffed blackbird was ignored. However, some jays are ignored near the nest; such birds were apparently non-breeding birds. The latter were sometimes observed to beg from mated males but were never fed. Others have observed such birds to aid in feeding the young in a nest, but this is probably unusual. Noisy groups of jays exhibiting much squabbling and antagonism were observed daily, but their significance is obscure. A second nest was begun two or three days after the disappearance of the eggs (incubation about eight or nine days) from a first nest. One pair deserted after a normal clutch of three had been laid, when an egg was removed from the nest each day to keep the total at one"--P. 20-21.
Description
22 p. ; 24 cm.
Includes bibliographical references (p. 21-22).
Includes bibliographical references (p. 21-22).
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