Literaturdatenbank
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Burger, J. P. (1977). Determinants of hatching success in diamondback terrapin, malaclemys terrapin terrapin. American Midland Naturalist, 97(2), 444–464.
Added by: Admin (25 Aug 2008 20:36:48 UTC) |
| Resource type: Journal Article BibTeX citation key: Burger1977 View all bibliographic details  |
Categories: General Keywords: Emydidae, Haltung = husbandry, Malaclemys, Malaclemys terrapin, Schildkröten = turtles + tortoises Creators: Burger Collection: American Midland Naturalist |
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| Abstract |
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Diamondback terrapin (Malaclemys terrapin Schoepff) were investigated in 1973 and 1974 in a sand dune colony at Brigantine National Wildlife Refuge, New Jersey , to study the factors determining hatching success. Nesting occurs from early June-mid-July, and nests were observed until early Oct. when the fate of all nests was known. Eighty-four percent (n = 32) of the nests had eggs hatch in 1973, but only 25% (n = 200) had eggs hatch in 1974. Nests that were not successful were preyed upon by fox, raccoon, gull and crow. Fox and raccoon predation occurred at night throughout the developmental period; gulls and crows were only successful at the time of egg laying. Mammalian predation was highest in the protected dune areas surrounded by trees and shrubs, and avian predation was highest in the open sand areas nearer the cove. The rate of predation is highest during the egg-laying and hatching period. Forty-five percent of the nests having hatchlings were preyed upon in this 4-10 day period. Early nests, initiated from June 1-29, had a lower predation rate (58%) than those initiated in July (80%). Nests (1546) were estimated in the study area by comparing predation rates on known nests with these previously undetected nests preyed upon in the area. The developmental period for eggs was 61-104 days. Within individual nests, eggs hatched in 1-4 days. This spread was positively correlated with the number of eggs and nest depth. Individual hatchlings emerged 1-9 days (.hivin.x = 2.5) after hatching. Emergence ranged from 1-11 days in an individual nest. Early emergence after hatching reduces the individual's chance of predation while in the nest.
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