Influence of Intrinsic Factors on At-Sea Behavior of Late Chick-Rearing Emperor Penguins (Aptenodytes Forsteri) at Cape Crozier, Ross Island, Antarctica
In this study, I described the at-sea behavior of emperor penguins (Aptenodytes forsteri) during late chick-rearing at Cape Crozier. By analyzing data from nine penguins, I investigated how intrinsic factors, including sex, size, and body condition influenced their behaviors. Penguins exhibited mean...
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Digital Commons @ CSUMB
2023
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| Online Access: | https://digitalcommons.csumb.edu/caps_thes_all/1573 https://digitalcommons.csumb.edu/context/caps_thes_all/article/2613/viewcontent/Parker_Forman_Thesis_CSUMB_230727.pdf |
| Summary: | In this study, I described the at-sea behavior of emperor penguins (Aptenodytes forsteri) during late chick-rearing at Cape Crozier. By analyzing data from nine penguins, I investigated how intrinsic factors, including sex, size, and body condition influenced their behaviors. Penguins exhibited mean trip durations of 10.6±3.4 days, covering a daily distance of 55.7±8.0 km. Penguins predominantly performed dives within the upper 200 meters of the water column (90.7±26.5%), with a smaller proportion of dives (9.3±2.0%) reaching greater depths. Deeper dives were typically associated with shallow bathymetry. Penguins conducted an average of 1,860±681 dives with maximum depths of 455.8±32.6 m and durations of 12.9±2.4 minutes. Penguins spent 66.4±14.8% and 43.9±4.4% of their time at sea resting and diving. Penguins with similar behaviors were categorized into groups: Group I and Group II traveled west, north, and northeast, and many traveled to the Ross Bank. I found significant differences in diving behaviors between the groups and sexes. The composition of these groups was influenced by sex. Group I mostly comprised males, while Group II were females and one unknown sex. Females displayed higher dive frequencies per day (Females (F): 186±17, Males (Males (M): 151±4), shallower maximum depths (F: 432.2±29.4 m, M: 476.8±12.8 m), and shorter durations (F: 3.2±0.7, M: 3.9±0.3). Possible explanations for the observed differences between male and female penguins include energetic requirements, prey preference, physical characteristics, and niche differentiation, which can shape their distinct foraging behaviors. Furthermore, results from this study indicate that penguin behaviors were also influenced by the physical characteristics and condition of their bodies. This finding suggests that there may be an optimal body condition for achieving greater diving depths. Penguins with intermediate body conditions may possess a more efficient physiological adaptation for sustained deep diving, enabling them to access resources ... |
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