Habituation of Adult Magellanic Penguins to Human Visitation as Expressed through Behavior and Corticosterone Secretion

Walker, Brian; Boersma, P. Dee; Wingfield, John C.

doi:10.1111/j.1523-1739.2005.00271.x

Cited by 218 publications

(179 citation statements)

References 44 publications

Supporting

Mentioning

164

Contrasting

Unclassified

Order By: Relevance

“…As penguins are commonly used as model species for hormonal and stress studies in birds (e.g. Holberton et al, 1996;McQueen et al, 1998;Fowler, 1999;Walker et al, 2005b;Walker et al, 2006), our results will be particularly valuable for the interpretation of previous studies, and for the undertaking of future studies.…”

Section: Introductionmentioning

confidence: 99%

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

et al. 2009

View full text Add to dashboard Cite

Abstract. Physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. Different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure they correlate.We directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the Adelie penguin (Pygoscelis adeliae). Blood and faecal samples were simultaneously collected from individual penguins for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher mean corticosterone concentrations than females, but the difference was only statistically significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males, perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Our data indicate that faecal sampling appears more suitable for assessing baseline hormone concentrations, while plasma sampling may best define immediate responses to environmental events. Consequently, future studies should ensure they select the most appropriate matrix and method of hormone measurement to answer their research questions.

show abstract

Section: Introductionmentioning

confidence: 99%

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

et al. 2009

View full text Add to dashboard Cite

show abstract

“…It has been widely used in field studies of species ranging from primates (Williamson & Feistner 2003;Aguiar & Moro-Rios 2009) Walker et al 2006), and has played a crucial role in elucidating the socio-ecology of many of these species.…”

Section: Introductionmentioning

confidence: 99%

Does watching a monkey change its behaviour? Quantifying observer effects in habituated wild primates using automated radiotelemetry

et al. 2010

View full text Add to dashboard Cite

In studies of animal behaviour, researchers have long been concerned that their presence may change the conduct of their study subjects. To minimize observer effects, researchers often habituate their study animals. The premise of this method is that, with sufficient neutral exposure, animals will stop reacting to humans. While numerous studies demonstrate that negative responses to humans decrease over time, the fact that an animal does not flee from or behave aggressively towards observers cannot be taken as evidence that it is not altering its behaviour in other, more subtle ways. Because remotely monitoring the behaviour of wild animals is difficult, it has not been possible to answer the critical question: do habituated animals change their behaviour when researchers are present? Here, we use data from an automated radiotelemetry system that remotely monitored the movement and activity of radiocollared animals to test whether observers affected the behaviour of seven habituated white-faced capuchins, Cebus capucinus. We found no evidence that observers influenced the ranging behaviour or activity patterns of their study subjects. Capuchins did not move faster, stop to rest less frequently, or display higher levels of activity when they were being followed compared to when they were alone. It has been suggested that researchers may embolden habituated study subjects, artificially increasing their relative dominance, but we found no relationship between observer presence and proximity to neighbouring social groups. Although it remains possible that observer effects existed but were too subtle to be detected with the remote sensing technology we used, the results of this study nevertheless provide reassuring evidence that humans can observe habituated wild animals without overly influencing the animals' activity and movement patterns. Ó

show abstract

“…We also found that having to cross a tourist footpath to reach their nest when entering or leaving the colony did not have increased basal CORT. In adults, penguins that lived near tourist areas had a diminished CORT response to capture stress than those living in more isolated areas (Fowler, 1999; Walker et al., 2006). Additionally, individuals living in more isolated areas had higher basal CORT than those living in tourist areas (Fowler, 1999).…”

Section: Discussionmentioning

confidence: 99%

Magellanic penguin telomeres do not shorten with age with increased reproductive effort, investment, and basal corticosterone

Cerchiara

Risques

Prunkard

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

All species should invest in systems that enhance longevity; however, a fundamental adult life‐history trade‐off exists between the metabolic resources allocated to maintenance and those allocated to reproduction. Long‐lived species will invest more in reproduction than in somatic maintenance as they age. We investigated this trade‐off by analyzing correlations among telomere length, reproductive effort and output, and basal corticosterone in Magellanic penguins (Spheniscus magellanicus). Telomeres shorten with age in most species studied to date, and may affect adult survival. High basal corticosterone is indicative of stressful conditions. Corticosterone, and stress, has been linked to telomere shortening in other species. Magellanic penguins are a particularly good model organism for this question as they are an unusually long‐lived species, exceeding their mass‐adjusted predicted lifespan by 26%. Contrary to our hypothesis, we found adults aged 5 years to over 24 years of age had similar telomere lengths. Telomeres of adults did not shorten over a 3‐year period, regardless of the age of the individual. Neither telomere length, nor the rate at which the telomeres changed over these 3 years, correlated with breeding frequency or investment. Older females also produced larger volume clutches until approximately 15 years old and larger eggs produced heavier fledglings. Furthermore, reproductive success (chicks fledged/eggs laid) is maintained as females aged. Basal corticosterone, however, was not correlated with telomere length in adults and suggests that low basal corticosterone may play a role in the telomere maintenance we observed. Basal corticosterone also declined during the breeding season and was positively correlated with the age of adult penguins. This higher basal corticosterone in older individuals, and consistent reproductive success, supports the prediction that Magellanic penguins invest more in reproduction as they age. Our results demonstrate that telomere maintenance may be a component of longevity even with increased reproductive effort, investment, and basal corticosterone.

show abstract

Habituation of Adult Magellanic Penguins to Human Visitation as Expressed through Behavior and Corticosterone Secretion

Cited by 218 publications

References 44 publications

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

Does watching a monkey change its behaviour? Quantifying observer effects in habituated wild primates using automated radiotelemetry

Magellanic penguin telomeres do not shorten with age with increased reproductive effort, investment, and basal corticosterone

Contact Info

Product

Resources

About