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Some aspects of the breeding biology of the snail kite in Florida

Journal of Field Ornithology

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Abstract

The breeding biology of the Snail Kite was studied in Florida from 1968-1977 and intermittently from 1978-1980. Breeding occurred every month, but not in the same year. Peak egg-laying occurred from February through April or generally about 8 1 d before the onset of the rainy season in mid- or late May. Courtship displays, copulation and duration of copulation are described. Mean egg-laying interval was 2.2 d, and clutch size ranged from 1-6 eggs (x = 2.92). The frequency of large clutches (4-6 eggs) was significantly greater before 1940 than after. Incubation, which was shared by both sexes, lasted 24-30 d (x = 27.4). Egg length and breadth, eggshell thickness and weight, and whole egg volume and weight are presented. Hatching success was 57.5%. Mean hatching success for all clutches was 1.7 young or 2.3 per successful clutch. Hatching success of 2- and 3-egg clutches did not differ significantly. The nestlin period averaged 28.7 d (range 23-34). The interval between fledging of the first and last nestling in 1 brood was up to 5 d. An average of 2.0 young were raised per successful nest, and 50.5% of the nests were successful. The mean percent of successful nests per year for the 11-yr period (excluding the drought year 1971 in which there was no nesting) was 56.5 (range 17.1-84.6/yr). Nestling mortality was 37% overall, but was less during favorable high water conditions. Twenty-two factors are identified as causing nesting failure in kites, principal among these was predation (44%).

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Some aspects of the breeding biology of the snail kite in Florida
Series title:
Journal of Field Ornithology
Volume
58
Issue:
2
Year Published:
1987
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
171-189
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
171
Last page:
189
Number of Pages:
19