Regulation of vernal migration in Gambel's white-crowned sparrows: Role of thyroxine and triiodothyronine.

摘要: Appropriate timing of migratory behavior is critical for migrant species. For many temperate zone birds in the spring, lengthening photoperiod initial cue leading to morphological, physiological and changes that are necessary vernal migration breeding. Strong evidence has emerged recent years linking thyroid hormone signaling photoinduction breeding while more limited information suggest a potential role regulation photoperiodic songbirds. Here we investigate development expression life history stage captive Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) hypothyroidic state, induced by chemical inhibition production. To explore possible variations effects two hormones, triiodothyronine thyroxine, subsequently performed coupled with replacement therapy. We found hormones resulted complete abolishment mass gain, fattening, muscle hypertrophy associated preparation as well resulting failure display nocturnal restlessness behavior. Replacement thyroxine rescued all these elements near control levels displayed partial or delayed rescue. Our findings support being morphology physiology itself.