Correlates of lifetime reproductive success in three species of European ducks

Abstract

Number of breeding attempts is a strong correlate of lifetime reproductive success (LRS) in birds, but the relative importance of potentially interacting factors affecting LRS has rarely been fully evaluated. We considered simultaneously five main factors hypothesized to influence LRS (age at first breeding, nesting date, number of breeding attempts, female traits, brood parasitism) by analyzing with path analysis 22-year data sets for 1,279 individually marked females and their offspring in tufted duck ( Aythya fuligula), common pochard ( A. ferina) and northern shoveler (Anas clypeata). We recaptured marked offspring as breeding adults (n=496 females) and obtained more complete estimates of LRS by incorporating information about banded ducklings of both sexes shot by hunters > or =12 months after banding (n=138). In tufted ducks and especially pochard (both diving duck species), late-hatched females tended to delay nesting until 2-years old. Most females (tufted duck, 74%; pochard, 71%; shoveler, 59%) apparently produced no breeding-age offspring. Number of breeding attempts (i.e., longevity) was the strongest correlate of LRS in all species, after controlling effects of age at first breeding, relative nest initiation date, wing length and body mass. Percentage of females producing recruits increased gradually with number of breeding attempts for all three species. Also, as expected, females nesting early in the breeding season had higher LRS than late-nesting individuals. In shoveler, female-specific characteristics of relatively longer wings and heavier late incubation body mass had positive effects on LRS, the latter feature being more common in 2-year-old nesters. In diving ducks, no relationships were detected between LRS and female-specific traits like wing length or body mass, and nor did acceptance of parasitic eggs have any deleterious impact on fitness estimates. Overall, number of fledged ducklings and LRS were related in tufted duck, weakly associated in pochard and unrelated in shoveler, implying that fledging success is not always a reliable measure of LRS.

Lifetime offspring production in relation to breeding lifespan, attractiveness, and mating status in male collared flycatchers

“…These individuals may also cope better with the costs of reproduction, and may attain higher success regardless of their lifespans. This explanation may be more consistent with our results than improving experience, as a large number of individuals produce no returning young despite breeding several times during their lives (also see Gustafsson 1989;Blums and Clark 2004). Females of many species apparently prefer older males (Enstrom 1993;Richardson and Burke 1999), or traits that indicate the expected lifespan of males (Jennions et al 2001), thereby often enhancing the quality of young they produce (Saetre et al 1995;Hegyi et al 2006b).…”

“…There are two main determinants of the number of lifetime recruits: lifespan and the number of recruits per breeding attempt. Several studies have identified longevity or the number of breeding attempts as an important determinant of LRS (birds : Gustafsson 1986;Merilä and Sheldon 2000;Blums and Clark 2004;mammals: Clutton-Brock 1988;Bérubé et al 1999). However, a prolonged lifespan in itself is not sufficient to be successful, as a considerable number of individuals do not produce any recruits despite their long reproductive lives (Gustafsson 1989;Blums and Clark 2004), and even individuals that do produce recruits vary greatly in productivity (Newton 1989).…”

“…Several studies have identified longevity or the number of breeding attempts as an important determinant of LRS (birds : Gustafsson 1986;Merilä and Sheldon 2000;Blums and Clark 2004;mammals: Clutton-Brock 1988;Bérubé et al 1999). However, a prolonged lifespan in itself is not sufficient to be successful, as a considerable number of individuals do not produce any recruits despite their long reproductive lives (Gustafsson 1989;Blums and Clark 2004), and even individuals that do produce recruits vary greatly in productivity (Newton 1989). In fast-living species that live for a short time but may produce numerous offspring per breeding attempt, the reproductive output in a single year has a greater influence on the LRS than in slowliving species (Saether and Bakke 2000).…”

Individual quality persists between years: individuals retain body condition from one winter to the next in Teal

“…Ducks (Anatidae) are among the species for which survival and breeding success have been shown to increase with body condition (Alisauskas and Ankney 1992;Blums and Clark 2004), but repeated body condition assessments of the same individuals through time have, again, mostly been performed on breeding birds, generally only females (e.g. Hepp and Kennamer 1993;Milonoff et al 2002;Blums et al 2005).…”

Lifetime reproductive success of Snowy Plovers in coastal northern California

“…Studies that examine the relationship between LRS and morphology are also common (Bryant 1989, Mills 1989, Krüger 2002, Blums and Clark 2004, MacColl and Hatchwell 2004. For instance, Jensen et al (2004) studied LRS of House Sparrows (Passer domesticus) and found that morphological traits, like badge size and bill length, explained a significant proportion of variation in male LRS.…”