Article Abstract:
The conclusions of Herman Bumpus' 1899 study regarding the survival of house sparrows during a winter storm were validated using a sample taken from an Ann Arbor sparrow population. Morphometric trends in the current population implied that larger males and intermediate females from the Bumpus sample should have higher survival rates. Females were also underrepresented, owing to the method of collection. Improvements in experimental methodology to evaluate the true presence of differential selection are specified.
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Article Abstract:
The breeding biology of Harris' sparrow and the white-crowned sparrow in the Northwest Territories were found to be very similar. Sex ratios, nesting cycles and physiologic changes were nearly identical. Low levels of intra- and interspecific agonistic interactions were observed. For both species, only females built nests, incubated and brooded young, but the male shared in feeding the nestlings. Nestling development proceeded among similar lines in both species.
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Article Abstract:
A study was conducted to examine the breeding readiness of migrant bird species ensnared in New York during the spring of 1995 and 1996. The study also analyzed the occurrence of enlarged cloacal proturberance, rate of early sperm release males and incidence of insemination in females for two years. Results indicated that the birds lacked early sperm production which could have resulted from depleted energetic stores.
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