Paper submitted

With Scott Hatch, Thomas Merkling, Sasha Kitaysky

Title: Food supplementation early in life delays viability selection in a long‑lived animal


Supplementation of food to wild animals is extensively applied as a conservation tool to increase local production of young. However, the effects of food supplementation on the subsequent recruitment as breeders of long-lived migratory animals into natal populations and their lifetime reproductive success are largely unknown. We examine how experimental food supplementation affects (a) recruitment as breeders of kittiwakes Rissa tridactyla born in a colony on Middleton Island (Alaska) between 1996 and 2006 (n = 1629) that bred in the same colony through 2013 (n = 235); and (b) breeding success of individuals that have completed their life cycle at the colony (n = 56). Birds were raised in nests that were either supplemented with food (Fed) or unsupplemented (Unfed). Fledging success was higher in Fed compared to Unfed nests. After accounting for hatching rank, growth, and oceanic conditions at fledging, Fed fledglings had a lower probability of recruiting as breeders in the Middleton colony than Unfed birds, but the per-nest contribution of breeders was still significantly higher for Fed nests. Lifetime reproductive success of a subset of breeders that completed their life cycle was not affected by the food supplementation during development. Our results cast light on the interaction between intrinsic quality and early food conditions in determining fitness of long-lived animals.

Keywords: Individual quality; supplemental feeding; long-lived animals; viability selection.