Effects of supplementation with preferred foods on the reproductive axis of American Goldfinches (Spinus tristis)

• Published in: Canadian journal of zoology Vol. 90; no. 2; pp. 203 - 209
• Main Authors: FURLONGER, A. A, HUYNH, L, LULOFF, T. W, SCHMIDT, K. L, MACDOUGALL-SHACKLETON, S. A
• Format: Journal Article
• Language: English
• Published: Ottawa NRC Research Press 01.02.2012; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal reproduction; Aves; Biological and medical sciences; Birds; Carduelis tristis; Diet; Females; Food; Fundamental and applied biological sciences. Psychology; Physiology; Plasma; Seeds; Testosterone; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Canada; Vertebrata; Reproduction; Supplementation; Aves
• ISSN: 1480-3283; 0008-4301; 1480-3283; 0008-4301
• DOI: 10.1139/z11-127

Numerous field studies indicate that food supplementation of birds can advance laying date. In addition, laboratory studies, though less common, suggest that altering the amount of food, the predictability of food, or food type can affect reproductive physiology. American Goldfinches (Spinus tristis, formerly Carduelis tristis (L., 1758)) breed in late summer when thistle (Cynareae) seeds become abundant, suggesting that specific food types may affect their reproductive physiology. We tested whether supplementation with preferred seeds would affect reproductive physiology of male and female American Goldfinches. Birds were photostimulated and fed a standard pellet diet, or supplemented with a variety of preferred seeds. Supplemented females developed larger ovarian follicles. Supplemented males had higher levels of plasma testosterone, but only if they were also housed with a female. These results suggest that preferred seed types can act as a supplementary cue in this species, and fine-tune photoperiod-driven changes in reproductive physiology.