• DOI:10.2307/1367443
• Corpus ID: 88007514

Endocrine Responses of White-Crowned Sparrows to Environmental Stress

@article{Wingfield1982EndocrineRO,
  title={Endocrine Responses of White-Crowned Sparrows to Environmental Stress},
  author={John C. Wingfield and Jan P. Smith and Donald Sankey Farner},
  journal={The Condor},
  year={1982},
  volume={84},
  pages={399-409}
}

• J. Wingfield, Jan P. Smith, D. Farner
• Published 1 November 1982
• Biology
• The Condor

--Field and laboratory investigations were conducted to assess the effects of selected stressors on White-crowned Sparrows (Zonotrichia leucophrys gambelii and Z. 1. pugetensis). Within a few minutes after capture during the nonbreeding winter phase, the birds' plasma corticosterone increased, whereas their already low levels of luteinizing hormone (LH) and dihydrotesterone (DHT) declined further. In contrast, in the summer, or breeding phase, corticosterone levels increased much more slowly (sometimes not at all in females) during the first hour after capture. Plasma levels of LH in breeding birds were unaffected by capture and handling, as were levels of DHT in males and estrogen in females. In some cases, however, circulating levels of testosterone declined in males. In photostimulated, caged, male Z. 1. gambelii circulating levels of corticosterone, LH, and DHT appeared to be unaffected by ambient temperatures between 50 and 320C, but the level of testosterone was significantly depressed at 320C. Capture, transport for 250 km, and subsequent caging of male and female Z. 1. gambelii in autumn and winter within 24 h increased plasma corticosterone, and decreased LH and DHT. As the birds acclimated to captivity, a decrease in levels of corticosterone was followed by transient elevations of LH and DHT after which concentrations of these hormones stabilized at capture levels. Males transferred from outdoor aviaries and held one, two, or three per cage on short days also developed elevated concentrations of corticosterone and depressed levels of LH and DHT. Corticosterone decreased within two weeks in birds held one or two per cage, and within three weeks in those housed three per cage. As corticosterone levels decreased, transient increases occurred in LH and DHT, with the highest levels in birds held three per cage. For more than half a century feral passerine birds have been used in investigations in both laboratory and field. Recently techniques have been developed to examine changes in endocrine status and in condition of the reproductive system of individually marked breeding birds in the field (Wingfield and Farner 1976, 1977, 1978a, b). However, relatively little consideration has been given to the development and effects of stress under the conditions of investigation. Although capture, handling, laparotomy, transport, and confinement in captivity are presumably stressful, we know of no attempt as yet to assess the role of these procedures as stressors in feral avian species. Such assessments are obviously critical for interpreting data on endocrine and gonadal function derived from such species in both the field and laboratory. In addition, they should provide insights into the underlying mechanisms of responses and adaptations of natural populations to stressful disturbances or alterations of the environment. Using a system first described six years ago (Wingfield and Farner 1976), we have assessed the effects of selected assumed stressors on the plasma concentrations of corticosterone, luteinizing hormone, and sex steroid hormones in White-crowned Sparrows (Zonotrichia leucophrys). MATERIALS AND METHODS