Behavior, physiology, biological age, and cultural role of long-lived Bering Sea seabirds

Abstract

This dissertation focuses on the intersection of behavior, physiology, and biological age. Biological age is a measure of an organism's progress through life, and it incorporates chronological age as well as the actions of environment and innate quality at the individual level. We estimate biological age using telomere length as a biomarker. Telomere degradation in relation to oxidative stress links it directly to purported proximate mechanisms of aging under the free radical theory of aging. Short telomeres, or telomere loss, have been related to ecological indicators of lowered fitness. Our work focuses on aging in the thick-billed murre (Uria lomvia), a long-lived seabird breeding in the Bering Sea. Seabirds exemplify the "slow-lived" paradigm; they have long lifespans, low reproductive rates, and high adult survival. First we address the relationship between chronological age and telomere length in the thick-billed murre. We found longer telomeres in chicks than in adults, and longer telomeres in adult females than in adult males. Then we examine biological age, telomere length, in relation to physiology and behavior of murres equipped with a recording device to monitor foraging behavior. Chapter two describes the physiological and reproductive investment of these murres in relation to their biological age, while chapter three addresses the habitat and prey choices made by these birds in relation to sex, biological age, and environment. Behaviorally murres remain healthy into their old ages, with physiological diving capacity similar or improved in old birds. Stress patterns demonstrate that when conditions are good, older birds are more stressed, but experience buffers their stress levels under poor conditions. The fourth chapter of this thesis deals with seabirds as part of the larger socio-ecological system that includes the indigenous people living on the Pribilof Islands. The Priblovians value seabirds, but are members of periphery communities troubled by a poor economy and disconnected from a past that was tightly coupled to the natural world. Development requires active management by local stakeholders to reconnect with cultural and economic resources (like seabirds) and to make the communities more sustainable and resilient.