Effects of Crowd Size, Composition, and Noise Level On Pool Use in a Mixed-Species Penguin Colony

Abstract

Studies on how visitors affect penguins in human care report a mixture of negative, neutral, and positive impacts on behavior and physiology. Swimming is a highly motivated behavior that may promote positive welfare in penguins. We investigated how visitor crowd size, composition, and noise levels impact pool use in a mixed-species colony housing king (Aptenodytes patagonicus; n = 20), gentoo (Pygoscelis papua; n = 14), and southern rockhopper (Eudyptes chrysocome; n = 24) penguins. We used video and sound loggers to record if penguins were on land or in water, the number of human adults and children present, and noise levels using 5-minute scan samples from 09:00-15:00 over 36 continuous days. Data were analyzed using linear mixed models with proportion of penguins in the water as the dependent variable and crowd size, composition, and noise levels in A-weighted (dBA) and C-weighted (dBC) scales as independent variables. Crowd size was positively associated with pool use in gentoo penguins. Crowd composition did not predict pool use in any species. Noise levels in dBA, which is adjusted to the higher frequencies of human hearing, positively predicted pool use in southern rockhopper penguins. Noise levels in dBC, which captures lower frequencies, did not predict pool use in any species. No evidence of negative visitor effects was observed. Instead, these results suggest visitors are a neutral stimulus to king penguins and may be enriching to gentoo and southern rockhopper penguins.

Dither: A unifying model of the effects of visitor numbers on zoo animal behavior

“…Many studies of visitor impacts on zoo animal behavior, even within the same species, have found contradictory results (Birke, 2002; Choo et al, 2011; Hashmi & Sullivan, 2020), and increasingly evidence suggests human presence may not be the largest predictor of animal behavior in zoos or aquariums (Edes et al, 2021; Rose et al, 2020). This is consistent with our findings, as even in cases where nonlinear models were the most supported by the data, their predictive strength was relatively weak in this study.…”

The Benefits of Increased Space and Habitat Complexity for the Welfare of Zoo-Housed King Penguins (Aptenodytes patagonicus)

“…Although we did not systematically assess visitor numbers, we observed the penguins in both habitats during periods when they were closed to visitors, and swimming patterns remained unchanged. Similarly, Edes et al [12] found no relationship between pool use and crowd size, crowd composition, or noise levels in king penguins living in another mixed-species zoo colony. Crowd size did not affect the pool use of captive Humboldt penguins, either [39].…”

“…Despite the popularity and charismatic nature of penguins, studies of their welfare were rare until recent years, with existing research focusing primarily on visitor effects [9][10][11][12][13][14][15][16]. Pool use has been a primary focus of other studies.…”

Sonic enrichment at the zoo

“…For instance, the presence of human visitors increased distress levels of wolves (Canis lupus) (Pifarré et al, 2012), pandas (Ailuropoda melanoleuca) (Quadros et al, 2014), orangutans (Pongo pygmaeus) (Birke, 2002), and koalas (Phascolarctos cinereus) (Larsen et al, 2014). The way animals use their enclosures can also be affected by the presence and location of humans visitors as shown with various penguins species (Chiew et al, 2020;Edes et al, 2021) and flamingos (Phoenicopterus roseus and Phoenicopterus chilensis) (Rose et al, 2021). According to Hosey, factors such as the temperament of a species or an individual, the presentation of the animals, and the behavior of the visitors when interacting with the animals determine whether zoo visitors have stressful effects on animals.…”