Non-invasive stress monitoring and temperament of chestnut-bellied seed-finch (Passeriformes, Thraupidae)

Songbirds are kept as pets around the world, and bird-singing contests occur in several countries. However, there is a lack of scientific support for songbird welfare and stress monitoring. Thus, we aimed to validate the measurement of glucocorticoid metabolites (GCM) concentrations in bird droppings as a way to assess endogenous adrenal activity in the chestnut-bellied seed-finch (Sporophila angolensis) by using an adrenocorticotropic hormone (ACTH) challenge. We also aimed to describe behaviors potentially indicative of stress and to evaluate the role of temperament in the expression of stress in this species. For the ACTH challenge, 12 seed-finch adult males were randomly submitted to one of the three treatments: S – 100 μL saline solution (control); D1 – 0.5 μg of ACTH; and D2 – 1.0 μg of ACTH. Total bird droppings were collected during pre-challenge and challenge days at intervals of four and two hours, respectively. We also quantified the total time birds spent on the following behavioral states: alertness, freezing, comfort, flying and foraging during the pre-challenge, challenge and post-challenge days. The birds’ temperament was assessed during three challenge tests involving novelty. The mean baseline GCM concentration, determined on the pre-challenge day, was 68.7 ± 20.2 ng/g of dry bird droppings. Birds that received treatments D1 and D2 showed an increase of 2.2 times in the GCM concentration 12 h after treatment injections. The chestnut-bellied seed-finch showed individual behavioral distinctiveness, which was correlated with the time they spent on foraging in response to acute stress. Our study showed that GCM concentration reflects endogenous adrenal activity in the chestnut-bellied seed-finch. However, this measure alone is not enough as an indicator of songbirds’ welfare. Therefore, the valences (positive or negative) of freezing, alertness, flying, and foraging behaviors can be used together with the physiological measure for noninvasive stress monitoring in S. angolensis.