Oxygen stores and foraging behavior of two sympatric, planktivorous alcids

Aquatic Biology

Anthony J. Gaston¹  Kevin L. Campbell¹  Akiko Shoji¹  Kyle Hamish Elliott¹ 

关键词: Cassin’s auklet;    Ptychoramphus aleuticus;    Ancient murrelet;    Synthliboramphus antiquus;    Reef Island;    Haida Gwaii;    Hemoglobin;    Myoglobin;   

DOI  :  10.3354/ab00236

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Seabird species with overlapping diets commonly coexist at breeding colonies. For example, ancient murrelets Synthliboramphus antiquus and Cassin’s auklets Ptychoramphus aleuticus are similar-sized small alcids that feed on krill and small fish. Little is known regarding their partitioning of aquatic resources, so we assessed the O₂ stores and foraging behavior of sympatrically breeding populations of these species. The attachment of recorders (1 to 3% of body mass) caused substantial nest desertion, but we reduced these effects by only equipping experienced birds early in the day. Auklets and murrelets had 18 to 24% higher mass-specific O₂ stores than slightly larger non-diving kittiwakes Rissa tridactyla. When compared to published values, blood hemoglobin content was higher, muscle pH buffering capacity was similar and muscle myoglobin content was lower for small divers than for larger non-phocid divers. The slightly higher O₂ stores of Cassin’s auklets was reflected in their aquatic behavior, as auklets dived longer than murrelets at any given dive depth. Moreover, chick-rearing auklets spent 31% more time underwater than incubating auklets and 50% more time underwater than incubating murrelets. In total, 45% of dives by chick-rearing auklets, 36% of dives by incubating auklets and 13% of dives by incubating murrelets exceeded their estimated aerobic dive limits. Murrelets primarily used V-shaped dives while auklets generally exhibited W-shaped dive profiles with a protracted bottom phase. Thus the O₂ stores and foraging behavior of the 2 sympatric seabirds differed.

【 授权许可】

Unknown