Establishment and Application of a Fecal Glucocorticoid Metabolite Assay for 4.1 Magellanic Penguins (Spheniscus Magellanicus) for the Assessment of Adrenal Activity in Conjunction with Behavioral Observations to Understand the Potential Impact Associated with Variables of Behind the Scenes Tours at a Zoological Facility
Date
2015-03-24
Authors
Hartell-DeNardo, Julie
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Abstract
An excrement glucocorticoid metabolite (GCM) assay was established for penguins and was applied as a tool, in conjunction with behavioral observations, to evaluate individual birds responses to participation in a behind the scenes tour program involving potential tactile interactions with zoo guests. An adrenocorticotrophic hormone (ACTH) challenge was used to validate a corticosterone assay for measuring GCM in Magellanic penguin excrement, as well as to develop individual GCM profiles consisting of maximum values, baseline, and percent change for each bird. The GCM assay was used in conjunction with behavioral and environmental data collected during behind the scenes tours as a means to quantify potential stress. Excrement samples and tour observations were collected daily from each bird for one week during which it participated, with a second bird, in tours with zoo guests twice daily. Excrement samples were also collected from each bird daily during one week in which it participated in no tours. Results indicate that both endocrine and behavioral responses to tours, and associated tour environment components, are variable among the individual birds. While three of the birds did not have significant changes in GCM values (F1,48 = 2.05, p = 0.16) on days they participated in tours, two birds did show increased GCM levels (F1,35 = 4.60, p = 0.04) on days that they participated in tours. These same two birds also showed a lower maximum response to ACTH challenge (= 1,205ng/g compared to =1,750ng/g), lower percent change between baseline GCM and ACTH maximum response (= 1,186% compared to = 5,851%), and had elevated baseline GCM levels (= 72.12ng/g compared to =33.77ng/g) relevant to the other three birds. These results may suggest a down-regulation in the ability of the HPA axis of these individual birds to respond to stress. This could be a result of chronic intermittent stress as part of their subjective experience and resulting affective states when participating in tours. These finding are similar to previous studies with other species that have found associations between chronic stress and compromised adrenal function. Behavioral data analysis showed increases in alternate head turn (AHT) behaviors correlate with lower GCM (F4,41 = 5.53, p = 0.02) and that AHT is positively correlated with reproductive (R), vocalization (V) and preening (P) behaviors. The lower GCM values may signify that higher AHT behavior rates imply a bird is comfortable within the tour environment and the association with R, V & P behaviors indicate the rates of these behavior may also be reflective of some level of comfort within the tour setting. Nip/bite (NB) behavior rates were positively correlated with all categories involving herding, an involuntary situation where staff manipulates a bird’s interaction with guests, and negatively correlated with voluntary approach of guests behaviors. This may indicate the infraction on a bird’s opportunity for choice, resulting from herding, may elicit behaviors undesirable in tour scenarios. Other behavioral correlations were specific to individual birds and pairing of birds further implicating the role of individual personality. Study results indicate that some individual animals maybe more suited to the role of ambassador animals within the zoo setting, and individual stress responses should be considered when choosing animals for guest interactions.
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Keywords
Magellanic Penguin, Zoo, GCM, ACTH, Corticosterone, Stress