Biology ETDs

Publication Date

5-1-1973

Abstract

The reproductive biology of the Band-tailed Pigeon (Columba fasciata) was studied from May through September during 1969-1972 in Colorado and during 1972 in New Mexico. Gonads, body weight, percent body fat, and crop activity from 619 male and female pigeons were used in the analyses of gonadal cycles of wild birds. Photoperiodic responses were studied experimentally during 1972-1973 to help explain the unusual reproductive patterns in this bird. The breeding season extends from May through August and two nesting attempts probably occur during this period. This pigeon normally lays one egg per clutch, but up to eight per cent of the females may lay two eggs _per clutch. Fall breeding was observed in one population of pigeons, indicating that Band-tailed Pigeons responded to environmental conditions other than photoperiod. The photo­periodic responses showed that these pigeons do not exhibit a characteristic refractory period and that testes responded to light periods as short as 10 hours. Ovarian follicles of unmated females can regress once they have become enlarged (e.g. greater than 5.5 nun in diameter). The testes of captive birds held in outdoor aviaries continued gonadal regression from 23 September 1972 until the winter solstice (during December), at which time they began to increase. Full breeding capability was reached during March 1973. Female pigeons housed with these males showed no follicle growth until March.

Language

English

Document Type

Thesis

Degree Name

Biology

Level of Degree

Masters

Department Name

UNM Biology Department

First Committee Member (Chair)

J. David Ligon

Second Committee Member

Clait E. Brawun

Third Committee Member

Donald Walter Duszynski

Fourth Committee Member

James Roman Gosz

Fifth Committee Member

Joe Scott Altenbach

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