Annual profile of fecal androgen and glucocorticoid levels in free-living male American kestrels from southern mid-latitude areas

Author(s)

Garcia Pereira, Ricardo Jose ^[1] ; Monteiro Granzinolli, Marco Antonio ^[2] ; Barbanti Duarte, Jose Mauricio ^[3]

Affiliation

^[1] Univ Estadual Paulista, Fac Ciencias Agr & Vet, Posgrad Dept Reprod Anim, BR-14884900 Jaboticabal - Brazil

^[2] Univ Sao Paulo, Dept Ecol, Lab Ecol Aves, BR-05508900 Sao Paulo - Brazil

^[3] Univ Estadual Paulista, Fac Ciencias Agr & Vet, Nucleo Pesquisa & Conservacao Cervideos, BR-14884900 Jaboticabal - Brazil

• Document type: Journal article
• Source: General and Comparative Endocrinology; v. 166, n. 1, p. 94-103, MAR 1 2010.
• Web of Science Citations: 8

Abstract

Fecal samples and behavioral data were collected at a fortnightly basis during 11 months period from free-living male American kestrels living in southeast Brazil (22 degrees S latitude). The aim was to investigate the seasonal changes in testicular and adrenal steroidogenic activity and their correlation to reproductive behaviors and environmental factors. The results revealed that monthly mean of fecal glucocorticoid metabolites in May and June were higher than those estimated in November. in parallel, monthly mean of androgen metabolites in September was higher than those from January to April and from October to November. Molt took place from January to March, whereas copulation was observed from June to October but peaked in September. Nest activity and food transfer to females occurred predominantly in October, and parental behavior was noticed only in November. Territorial aggressions were rare and scattered throughout the year. Multiple regression analysis revealed that fecal androgen levels are predicted by photoperiod and copulation, while fecal glucocorticoid levels are only predicted by photoperiod. Bivariate correlations showed that fecal androgen metabolites were positively correlated with fecal glucocorticoid metabolites and copulation, but negatively correlated with molt. Additionally, copulation was positively correlated with food transfer to females and nest activity, but negatively correlated with molt. These findings suggest that male American kestrels living in southeast Brazil exhibit significant seasonal changes in fecal androgen and glucocorticoid concentrations, which seem to be stimulated by decreasing daylength but not by rainfall or temperature. (C) 2009 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 05/01927-4 - Behavioral and endocrinological monitoring of the annual reproductive activity of free-ranging American kestrel males (Falco sparverius)
• Grantee: Ricardo Jose Garcia Pereira
• Support Opportunities: Scholarships in Brazil - Doctorate