Influences of weather on reproductive function in male Song sparrows, Melospiza melodia
Article first published online: 20 AUG 2009
1985 The Zoological Society of London
Journal of Zoology
Volume 205, Issue 4, pages 525–544, April 1985
How to Cite
Wingfield, J. C. (1985), Influences of weather on reproductive function in male Song sparrows, Melospiza melodia. Journal of Zoology, 205: 525–544. doi: 10.1111/j.1469-7998.1985.tb03542.x
- Issue published online: 20 AUG 2009
- Article first published online: 20 AUG 2009
- Accepted 12 June 1984
The avian reproductive cycle is integrated and timed by a variety of environmental factors that include day length, availability of food, nest sites, presence of a mate, etc. However, reproduction can be delayed or disrupted by inclement weather and, until recently, the endocrine responses of avian species to storms were entirely unknown. This communication describes changes in endocrine state in free-living male Song sparrows, Melospiza melodia, during gonadal recrudescence after a severe winter, and in response to storms in early spring and summer. Both the severe winter weather and an early spring snow storm delayed testicular development, and depressed circulating levels of testosterone. The sparrows did not appear to be stressed, however, since body mass and fat deposits were higher than in birds sampled during the previous spring after a less severe winter.
A second storm occurred in late May and early June when Song sparrows were feeding young. Curiously, plasma levels of testosterone were not affected, but the sparrows did appear to be stressed since there was a significant decline in body mass, and a marked increase in circulating levels of corticosterone. These data suggest that the effects of inclement weather on reproductive function can vary in relation to the stage in the reproductive cycle when the storm strikes, and that the endocrine mechanisms underlying acclimatization to severe meteorological conditions are also different.