Ecology and energetics of breeding Puffins (Fractercula artica) : variations in individual reproductive effort and success

• Main Author: Wernham, C.V.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Stirling 1993
• Subjects: Atlantic puffin May; Isle of (Scotland); Puffins May; Bird populations May; Burrows; artica; Atlantic puffin; fratercula; Fratercula arctica
• Online Access: http://hdl.handle.net/1893/29385; http://dspace.stir.ac.uk/bitstream/1893/29385/1/Wernham.pdf

This study investigated reproductive effort and success of individual Atlantic Puffins (Fratercula arctica) on the Isle of May, Firth of Forth, Scotland. It placed particular emphasis on the role of body condition in breeding. An energetics approach was taken, where individual ’quality’ was considered in terms of foraging efficiency. The study also investigated whether breeding entailed costs for Puffins, in terms of individual survival and future reproductive potential, and whether such costs were mediated through body condition. Colour-ringed pairs of Puffins were followed through 3 successive breeding seasons and their reproductive performance and condition were monitored. Energy reserves carried by individuals (body condition indices) were estimated from live mass and body dimensions, using a carcass-derived equation to predict lean wet mass. Attempts were made at increasing the effort of rearing young, by playing chick begging calls and exchanging chicks between burrows, and decreasing effort, by supplementary feeding of young. Field energy expenditures were measured for a sample of parents during chick rearing using the doubly-labelled water technique, and these were compared with other potential measures of reproductive effort. The breeding success of individual parents was not related to body condition when a correlative approach was taken. Field metabolic rates (FMR’s) of 9 adults rearing young averaged 3.67 +/- 0.65 s.d cm' CO2 g'd ' or 874 +/- 151 kJd ' (c.3.5 times basal metabolic rate). Individual FMR’s were not related to other measures of reproductive effort used in the study. The above results were evaluated using graphical models, to demonstrate mechanisms by which the confounding effects of inter-individual differences in foraging efficiency on body condition could mask relationships between body condition, FMR and reproductive performance. The body condition of parents which experienced a decrea.se in rearing effort or an increase in effort did not differ significantly from that of controls at ...