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Kimberly Jan Fernie,^1,2 David Michael Bird,¹ and Denis Petitclerc³

¹Natural Resource Sciences, McGill University, Quebec, Quebec, Canada
²Toxicology Centre and Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
³Agriculture and Agri-Food Canada, Lennoxville, Quebec, Canada

Abstract

Birds reproduce within electromagnetic fields (EMFs) from transmission lines. Melatonin influences physiologic and behavioral processes that are critical to survival, and melatonin has been equivocally suppressed by EMFs in mammalian species. We examined whether EMFs affect photophasic plasma melatonin in reproducing adult and fledgling American kestrels (Falco sparverius) , and whether melatonin was correlated with body mass to explain previously reported results. Captive kestrel pairs were bred under control or EMF conditions for one (short-term) or two (long-term) breeding seasons. EMF exposure had an overall effect on plasma melatonin in male kestrels, with plasma levels suppressed at 42 days and elevated at 70 days of EMF exposure. The similarity in melatonin levels between EMF males at 42 days and controls at 70 days suggests a seasonal phase-shift of the melatonin profile caused by EMF exposure. Melatonin was also suppressed in long-term fledglings, but not in short-term fledglings or adult females. Melatonin levels in adult males were higher than in adult females, possibly explaining the sexually dimorphic response to EMFs. Melatonin and body mass were not associated in American kestrels. It is likely that the results are relevant to wild raptors nesting within EMFs. Key words: American kestrel, birds, electromagnetic fields, EMF, melatonin, photoperiod. Environ Health Perspect 107:901-904 (1999) . [Online 13 October 1999]

http://ehpnet1.niehs.nih.gov/docs/1999/107p901-904fernie/ abstract.html

Address correspondence to K.J. Fernie, Natural Resource Sciences, McGill University, 21111 Lakeshore Rd., Ste. Anne de Bellevue, Quebec, Quebec, Canada H9X 3V9. Telephone: (514) 398-7932. Fax: (514) 398-7990. E-mail: kfernie@yahoo.com

We thank I. Ritchie, J. Negro, P. Lagüe, E. Block, D. Nguyen, T. Marchant, and K. Steenhof.

K.J.F. was supported by grants from the John K. Cooper Foundation, McGill University, the Wilson Ornithological Society, the Province of Quebec Society for the Protection of Birds, and the International Osprey Foundation Endowment Fund. D.M.B. received an NSERC Infrastructure Grant.

Received 14 April 1999 ; accepted 2 July 1999.