PATTERNS OF FLOCK SIZE, DIET, AND VIGILANCE OF NATURALIZED MONK PARAKEETS IN HYDE PARK, CHICAGO
PATTERNS OF FLOCK SIZE, DIET, AND VIGILANCE OF NATURALIZED MONK PARAKEETS IN HYDE PARK, CHICAGO
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芝加哥海德公园归化僧侣鹦鹉的群体大小、饮食和警惕性模式
DOI:
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发表时间:
2000
期刊:
影响因子:
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通讯作者:
S. Pruett
中科院分区:
文献类型:
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作者:
J. South;S. Pruett
Abstract We examined patterns of diet, foraging group size, and vigilance effort of naturalized Monk Parakeets (Myiopsitta monachus) in Hyde Park, a neighborhood of Chicago, Illinois. Parakeets exhibited a highly seasonal and varied diet consisting of fruits, seeds, and buds, and they fed almost exclusively on birdseed provided at backyard feeding stations during the winter months. Birds foraged in groups of 1 to 31 birds, but most flocks were of 10 birds or less. Foraging group size was greatest in the fall and early winter, and smallest at the beginning of the spring when breeding began. Monk Parakeets adjusted their vigilance effort with changes in flock size. Individual vigilance effort declined with increasing flock size through a decrease in time spent scanning as well as the number of times scans were initiated. The number of parakeets exhibiting vigilance in a flock at any given time also decreased with flock size. It is likely that the highly adaptable and varied diet of Monk Parakeets contributes greatly to the persistence and growth of populations in a variety of North American habitats.