Fatty acid analysis of the diet of Leach's Storm-Petrels

Logan, Matthew Shane (2007) Fatty acid analysis of the diet of Leach's Storm-Petrels. Masters thesis, Memorial University of Newfoundland.

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Abstract

Leach's Storm-Petrels (Oceanodroma leucorhoa) display variation in foraging durations and forage at a wide range of distances from the colony, preying on species in both neritic and pelagic environments. Diet of Leach's Storm-Petrel adults and chicks may contain different proportions of different types of prey due to forging trip lengths and digestion. Fatty acid signature analysis was used to analyze the diets of Leach's Storm-Petrel parents and chicks. Lipids were extracted from stomach regurgitations, bird tissues and prey items. Multivariate techniques were used to examine the differences between groups (i.e. parents and their chicks, males and females, and breeding years) in fatty acid signatures of adipose tissue samples. -- Physical properties of Leach's Storm-Petrel regurgitate were found to be significantly different between the incubation and chick-rearing periods. Significant differences in fatty acid signatures of Leach's Storm-Petrels were found between adults and their chicks and breeding years. Fatty acid signatures were then compared to a library of individually discernable fatty acid signatures of potential prey items within a new dietary reconstruction model, and estimates of prey composition were calculated. Fish and crustaceans were dominant prey types depending upon the pre-calculated calibration coefficients that were used in the model. Crustacean species were shown to be more significant to dietary composition than previous stomach content estimates have calculated. Significant differences were observed between prey composition estimates of adults and their offspring, but no significant differences were found between the sexes. Adults tended to consume more pelagic prey and fed a higher proportion of neritic prey to their offspring.

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