Carry-over effects of food supplementation on recruitment and breeding performance of long-lived seabirds

Abstract

Supplementation of food to wild animals is extensively applied as a conservation tool to increase local production of young. However, in long-lived migratory animals, the carry-over effects of food supplementation early in life on the subsequent recruitment of individuals into natal populations and their lifetime reproductive success are largely unknown. We examine how experimental food supplementation early in life affects: (i) recruitment as breeders of kittiwakes Rissa tridactyla born in a colony on Middleton Island (Alaska) between 1996 and 2006 (n ¼ 1629) that bred in the same colony through 2013 (n ¼ 235); and (ii) breeding success of individuals that have completed their life cycle at the colony (n ¼ 56). Birds were raised in nests that were either supplemented with food (Fed) or unsupplemented (Unfed). Fledging success was higher in Fed compared with 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. The per-nest contribution of breeders was still significantly higher for Fed nests because of their higher productivity. Lifetime reproductive success of a subset of kittiwakes that thus far had completed their life cycle was not affected by the food supplementation during development. Our results cast light on the carry-over effects of early food conditions on the vital rates of long-lived animals and support food supplementation as an effective conservation strategy for long-lived seabirds.

Effects of developmental conditions on growth, stress and telomeres in black‐legged kittiwake chicks

“…Supplemental feeding in kittiwakes had strong effects on wing growth, mass gain and antioxidant levels. Growth rates are often linked to food availability in seabirds (Lyons & Roby, ; Ricklefs, Duffy, & Coulter, ; Romano, Piatt, & Roby, ; Shea & Ricklefs, ), and in this study system, this finding has been extensively documented, along with effects on adult reproductive success and recruitment of fed and unfed chicks (Gill & Hatch, ; Vincenzi, Hatch, Merkling, & Kitaysky, ; Vincenzi et al., ; Welcker et al., ). As this relationship between food availability and growth is well described in this system, and our findings in this study corroborate the relationship, we refrain from discussing these effects further here.…”

Maternal effects as drivers of sibling competition in a parent–offspring conflict context? An experimental test

“…Hence, we expected environmental conditions to be on the right side of Figure 1, but with the Fed group obviously representing higher food availability than the Unfed group. Pairs experimentally fed throughout the breeding season (i.e., mimicking exceptionally good conditions) indeed have a consistently higher productivity than control pairs (0.4 more fledglings/nest in average: Vincenzi et al 2015). We thus hypothesized that the Unfed group was situated on the right of the parent-senior chick conflict zone of Figure 1, whereas the Fed group was situated in the zone of nonconflict on the right of Figure 1.…”

Sex and hatching order modulate the association between MHC‐II diversity and fitness in early‐life stages of a wild seabird

“…Here, we investigated whether differences in sex and hatching order are associated with variation in the fitness consequences of MHC class-II diversity during the nestling stage in a wild population of the monogamous black-legged kittiwakes (Rissa tridactyla). In kittiwakes, female and second-hatched chicks are smaller, grow slower (Merkling et al, 2012;Vincenzi, Hatch, Mangel, & Kitaysky, 2013;Vincenzi, Hatch, Merkling, & Kitaysky, 2015) and suffer more from sibling aggressions (Delaunay, 2018;White, Leclaire, et al, 2010) than other chicks, suggesting that they are less competitive for food and in poorer condition. In several other species, including birds, food shortage and reduced condition have been linked to reduced immune responses via energy trade-offs (Beldomenico & Begon, 2010;Brzek & Konarzewski, 2007) or chronic stress (Glaser & Kiecolt-Glaser, 2005).…”

“…We tested several fitness-related traits, namely survival in the nest, growth rate and tick infection during the nestling stage. Growth rate is an important component of fitness in kittiwakes because faster growing chicks are more likely to recruit as breeders (Vincenzi et al, 2015). Ticks can have strong deleterious effects on kittiwake chicks by reducing growth rate when food is scarce (McCoy, Boulinier, Schjorring, & Michalakis, 2002), potentially leading to death in the case of hyperinfestation (Chastel, Monnat, Lelay, & Balouet, 1987).…”