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General and Comparative Endocrinology
Testosterone, corticosterone, and photoperiod interact to regulate plasma levels of binding globulin and free steroid hormone in dark-eyed juncos, Junco hyemalis.
Corticosterone and testosterone may interact in a complex manner in species that lack sex hormone binding proteins, and levels of CBG in Dark-eyed Juncos are regulated by both testosterone and day length. Expand
Corticosterone and corticosteroid binding globulin in birds: relation to urbanization in a desert city.
It is proposed that more predictable resources in the city than in rural areas may decrease the need to vary stress responsiveness across life history stages, highlighting the species-specific effects of urbanization on stress physiology and the difficulty to predict how urbanization impacts organisms. Expand
Seasonal changes of the adrenocortical responses to stress in redpolls, Acanthis flammea, in Alaska
The data suggest that redpolls may be able to adjust their responsiveness to acute stresses in relation to fat stores, as those with greater fat depots had reduced responsiveness to stress. Expand
Acute stress rapidly decreases plasma testosterone in a free-ranging male songbird: potential site of action and mechanism.
The observed acute stress-induced decrease in plasma T was apparently not mediated by decreased responsiveness of the pituitary gland to GnRH or of the testes to LH, and indicates that effects of stress may have been mediated at the pituitsary gland and also directly at the testicular levels. Expand
Context-specific territorial behavior in urban birds: No evidence for involvement of testosterone or corticosterone
Investigating behaviors in response to simulated territorial intrusions in urban and nearby desert populations of two Sonoran Desert birds and the degree to which these behaviors are mediated by testosterone (T) and the adrenal steroid, corticosterone (CORT), found associations between territorial behavior and habitat characteristics were not related to plasma T or CORT. Expand
Unpredictable food availability induces metabolic and hormonal changes independent of food intake in a sedentary songbird
The chronic stress hypothesis is supported and birds such as thrashers may be particularly susceptible to the perception of unpredictable variation in food supplies independent of actual energetic constraints. Expand
Seasonal and age-related changes in blood parasite prevalence in Dark-eyed Juncos (Junco hyemalis, Aves, Passeriformes).
Seasonal changes in blood parasite infections in a free-living population of Dark-eyed Juncos breeding in interior Alaska are determined and neither an association between parasite species nor a consistent relationship between parasite intensity and body condition is observed. Expand
Androgen control of vocal control region volumes in a wild migratory songbird (Junco hyemalis) is region and possibly age dependent.
Investigation of naturally occurring seasonal changes in the sizes of vocal control regions in a wild migratory species with samples from adolescence to post-breeding fall migration finds that area X size in adolescent male juncos may be testosterone independent. Expand
Interspecific variation in avian blood parasites and haematology associated with urbanization in a desert habitat
Many avian species are negatively impacted by urbanization, but other species survive and prosper in urbanized areas. One factor potentially contributing to the success of some species in urban areasExpand