Fecal corticosterone excretion in captive healthy and feather picking African grey parrots (Psittacus erithacus)

Abstract

Feather picking (FP) is a common problem in companion parrots, especially in African grey parrots (Psittacus erithacus). Many hypothesis have been made about this self-mutilating behavior, and serious psychological conflicts can play a pivotal role in the initiation of this self-defeating and self-punishing behaviour. Even though ethological distress is difficult to study, the monitoring of fecal corticoids is a useful non-invasive tool that can be used to assess stress in animals. The purpose of the present study was to compare the fecal corticosterone levels of companion African grey parrots kept as wild-type parrots (WT), healthy pet parrots (HP) and feather picking pet parrots (FPP) during the breeding season and out of the breeding season. An African grey parrot group, composed of 82 individuals, has been studied; these birds were divided into three sub-groups: 1) WT, parrots that were reared by their biological parents, kept in couples and with a regular reproduction activity; 2) HP, parrots that were hand-reared, but did not show any FP symptoms; 3) FPP, parrots that were hand-reared and that showed signs of FP. Fecal samples were collected in the morning on alternate days, during the breeding seasons and out of the breeding season. The fecal corticosterone and immunoreactive corticosterone metabolites were determined using a pan-specific corticosterone enzyme immunoassay kit (K014; Arbor Assays®, Ann Arbor, MI) validated for dried fecal extracts. Analysis of Variance was used to examine any variations due to the breeding season and among the groups of parrots. WT and HP parrots showed lower corticosterone levels than FPP parrots. The fecal corticosterone concentration showed an average (sum of the two seasons) of 74.10 ± 16.89 ng/g in the WT parrots; 79.56 ± 21.23 ng/g in the HP parrots and 185.53 ± 34.83 in the FPP parrots. A statistical trend between fecal corticosterone concentration in the different seasons for the WT parrots (P=0.085) was observed, but not for the other groups. The results suggest that 1) the highest levels of fecal corticosterone are excreted by birds affected by FP; 2) the observed highest level of corticosterone in FPP parrot suggests a role of stress in this self-injuring stereotypic behavior.