Influence of Age and Dispersal on Reproductive Success of Cliff Swallows (Petrochelidon Pyrrhonata) (original) (raw)
Related papers
Journal of Animal Ecology, 2001
1We describe age-related reproductive performance and recapture rates of tree swallows (Tachycineta bicolor Vieillot) based on a 25-year study of a nestbox population in south-eastern Ontario, Canada (1975–99).2Performance improved from first-time breeders to intermediate-aged birds. Nest initiation advanced, and clutch size increased in both sexes. In females the number of hatchlings and fledglings increased, and the proportion of nests failing completely declined. Performance declined in females after ‘middle-age’, in the number of young fledged, and the proportion of young fledged relative to initial clutch and brood size. Also, the proportion of nests that failed completely increased in the oldest birds. Males showed similar patterns.3An index of performance incorporating clutch size, hatching and fledging efficiency, and two measures of total nest failure increased to, then declined after, 4 years of age in females and 3 years in males. The relationship between this index and age was best predicted by quadratic regression.4We found no support for three of four hypotheses to explain improvement in performance with age. Recapture rates declined after age 4Y in males, but remained unchanged in females until age 7Y +, while output decreased in both sexes (Residual Reproductive Value). Birds breeding repeatedly did not perform better during their first attempt compared to birds that bred only once (Selection). Birds with varied breeding experience did not differ in their performance within age-groups (Breeding Experience). We did find support for the Breeding Age hypothesis; in females with no breeding experience, there was a successive advance in laying and increase in clutch size from 2 to 4 years of age.5Improved performance may be due to skills acquired with age, such as those devoted to feeding and balancing energy demands, which are necessary to prepare and maintain individual condition prior to, and during, breeding. Senescence in performance after ‘middle-age’ may result from accumulated costs of previous breeding effort which have been identified in this species based on research elsewhere.We describe age-related reproductive performance and recapture rates of tree swallows (Tachycineta bicolor Vieillot) based on a 25-year study of a nestbox population in south-eastern Ontario, Canada (1975–99).Performance improved from first-time breeders to intermediate-aged birds. Nest initiation advanced, and clutch size increased in both sexes. In females the number of hatchlings and fledglings increased, and the proportion of nests failing completely declined. Performance declined in females after ‘middle-age’, in the number of young fledged, and the proportion of young fledged relative to initial clutch and brood size. Also, the proportion of nests that failed completely increased in the oldest birds. Males showed similar patterns.An index of performance incorporating clutch size, hatching and fledging efficiency, and two measures of total nest failure increased to, then declined after, 4 years of age in females and 3 years in males. The relationship between this index and age was best predicted by quadratic regression.We found no support for three of four hypotheses to explain improvement in performance with age. Recapture rates declined after age 4Y in males, but remained unchanged in females until age 7Y +, while output decreased in both sexes (Residual Reproductive Value). Birds breeding repeatedly did not perform better during their first attempt compared to birds that bred only once (Selection). Birds with varied breeding experience did not differ in their performance within age-groups (Breeding Experience). We did find support for the Breeding Age hypothesis; in females with no breeding experience, there was a successive advance in laying and increase in clutch size from 2 to 4 years of age.Improved performance may be due to skills acquired with age, such as those devoted to feeding and balancing energy demands, which are necessary to prepare and maintain individual condition prior to, and during, breeding. Senescence in performance after ‘middle-age’ may result from accumulated costs of previous breeding effort which have been identified in this species based on research elsewhere.
Journal of Animal Ecology, 2000
1. One way that animals may select breeding sites is by assessing the reproductive success of conspeci®cs in one season and settling the next year in those habitat patches where success collectively had been greatest. This sort of habitat assessment may promote the formation of colonies at high quality sites. 2. We examined whether cli swallows, Petrochelidon pyrrhonota, in southwestern Nebraska used conspeci®c breeding performance to choose colony sites. 3. Reproductive success at colony sites varied spatially within seasons and between seasons, and was autocorrelated at a site from one year to the next, but not over longer time intervals. Cli swallows thus met the conditions for potential use of information on conspeci®c breeding performance. 4. Among sites re-used in consecutive years, those with highest collective success in one season showed the greatest rates in colony growth the next season, including the greatest in¯ux of immigrants. 5. The probability of colony-site re-use in successive years increased with collective reproductive success and average breeder body mass (a measure of individual condition) the previous season. 6. Cli swallows probably use conspeci®c breeding performance in selecting colonies. This mechanism is one component of habitat selection that also includes attraction to conspeci®cs and assessment of an individual's own success.
Local breeding experience and the reproductive performance of Tree Swallows
Journal of Field Ornithology, 2010
The potential advantages of repeated breeding at a particular location should improve reproductive performance in long-lived species of birds. However, for short-lived species, natural selection should favor individuals that most quickly develop competency in reproduction. Therefore, we hypothesized that local breeding experience beyond the first breeding attempt at a particular location would have little effect on subsequent reproductive performance of Tree Swallows (Tachycineta bicolor), a species where about 50% of adults breed only once in their lives. We tested this hypothesis using data collected from Tree Swallows in Michigan from 1993 to 2002. Because we were specifically interested in examining the effects of local breeding experience on reproductive performance, we restricted our analyses to after-second-year (ASY) females and their mates that we first encountered as breeders. Consistent with our hypothesis, we found no relationship between repeated local breeding experience and the reproductive performance of ASY female Tree Swallows and their mates as measured by clutch size and number of fledged young. However, pairs with more combined total local experience tended to lay eggs earlier in the season. These results suggest that Tree Swallows may benefit from breeding site fidelity, not because repeated local experience improves reproductive performance as measured by the production of fledglings, but because returning individuals acquire nest cavities earlier and are able to begin breeding earlier, providing time to renest in case of early nest failure.
2012
We investigated differences in ageing patterns in three measures of breeding performance in populations of barn swallows Hirundo rustica L. from Spain and Denmark differing in breeding latitude and hence migration distance and duration of the breeding season. We found differences in ageing patterns between populations. Generally, young (i.e. yearling) and old females (i.e. ! 5 years of age) laid their first eggs later and produced smaller clutches than middle-aged females (i.e. 2-4 years of age) in both populations. The southernmost population (i.e. Spanish) showing the shorter migratory distance experienced a greater within-individual increase in timing of breeding and clutch size in early life and a greater within-individual decrease in laying date but not in clutch size during senescence compared with the northernmost population (i.e. Danish). We also found that the number of fledglings produced annually was related to the age of the two members of the breeding pairs with pairs composed of young and old females performing less well than breeding pairs composed of middle-aged females. We did not find reproductive senescence for the age of the male while controlling for the age of the female on the number of fledglings produced annually by the breeding pair. Differential survival between individuals did not explain age effects on laying date or annual clutch size in neither population. However, the increase in the number of fledglings produced annually with age was partly explained by the disappearance of poor-quality members of the pairs, mainly poor-quality males. Age-related breeding success (i.e. number of fledglings) was similar for barn swallows from Spain and Denmark. Therefore, the study of ageing patterns and life-history strategies in free-ranging animals from more than a single population can throw new light on life-history theory, population dynamics and evolutionary studies of senescence.
Effects of Spring Migration Distance on Tree Swallow Reproductive Success Within and Among Flyways
Frontiers in Ecology and Evolution
During migration, animals may experience high rates of mortality, but costs of migration could also be manifested through non-lethal carry-over effects that influence individual success in subsequent periods of the annual cycle. Using tracking data collected from light-level geolocators, we estimated total spring migration distance (from the last wintering sites to breeding sites) of tree swallows (Tachycineta bicolor) within three major North American flyways. Using path analysis, we then assessed direct and indirect effects of spring migration distance on reproductive performance of individuals of both sexes. When these data were standardized by flyway, females fledged 1.3 fewer young for every 1,017 km they traveled, whereas there was no effect of migration distance on reproductive success in males. In comparison, when these data were standardized across all individuals and not by flyway, longer migrations were associated with 0.74 more young fledged for every 1,017 km traveled by females and 0.26 more young fledged for every 1,186 km migrated by males. Our results suggest that migration distance carries over to negatively influence female reproductive success within flyways but the overall positive effect of migration distance across flyways likely reflects broader life-history differences that occur among breeding populations across the tree swallow range.
AGE, 2005
A. P. Moller, F. de Lope and N. Saino: Reproduction and migration in relation to senescence in the barn swallow Hirundo rustica: A study of avian Fcentenarians_. Senescence reflects the decrease in age-dependent residual reproductive value, and a previous study of a cohort of migratory barn swallows (Hirundo rustica) that had reached advanced ages for this species (at least five years old) provided evidence consistent with senescence such as reduced reproductive performance and increased abundance of parasites. We studied a population of migratory barn swallows over a number of years. Several questions were asked including 1) how do longer lived birds compare to shorter lived individuals of the same species, 2) is there a difference in individuals of the same species that live in different geographical regions, and 3) how do patterns of reproduction change during aging? We compared the phenotypes of 87 individuals from three populations in Denmark, Italy and Spain that had reached at least five years old with those of control individuals matched for sex, arrival date and breeding site. These controls only became one year old, i.e., they were not found thereafter and both groups of individuals were compared in their first year of life. Results showed that there were no significant differences in any of 11 morphological characters or in the abundance of three ectoparasites between the two groups of birds. Females that eventually became very old had relatively smaller first clutches as one year olds than did one year old controls, while males that eventually became very old had mates that laid clutches that were relatively larger than those of controls. Annual fecundity showed a similar pattern, with an increased sex difference in fecundity between birds from Spain than in Italy and in Denmark. Danish barn swallows that achieved older ages had relatively lower haematocrits than control individuals of the same sex, age and arrival date captured at the same site, while the difference in haematocrits between these two categories of individuals was small for Italian birds. Spring arrival date was relatively earlier in Danish males that eventually became very old compared to control males of the same age and tail length (a correlate of fitness) that arrived at the same site, while the two age categories of females did not differ in arrival date. In the Spanish population there was no difference in arrival date between the birds that aged most successfully and controls for either sex. We will discuss these findings in relation to current senescence theories.
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Density-dependent age at first reproduction in the eastern kingbird
Oikos, 2009
Theory predicts that maximal fitness is obtained by individuals who begin to breed immediately upon reaching sexual maturity. However, delayed breeding occurs regularly in some taxa, and in birds and mammals is most often associated with long lifespan and/or limited access to suitable habitats. Delayed breeding is not expected among relatively short-lived species such as migratory passerine birds, but this assumption remains untested in many species. Here we quantify age at first reproduction in an eastern kingbird Tyrannus tyrannus population breeding in an ecological island, and through both observational and experimental approaches, investigate the potential causes for the high frequency of delayed breeding that occurs in this population. Nearly half of the fledged nestlings that returned to the breeding grounds did not breed in their first potential breeding season. Some non-breeders occupied territories, for at least some period, but most remained as non-territorial ‘floaters’. Parentage analysis failed to show any reproductive success for female floaters, and only limited success for male floaters, indicating that floating was not a successful reproductive tactic. On the other hand, a strong negative relationship existed between population size and the proportion of young birds that bred in their first year, and non-territorial birds of both sexes quickly filled territory vacancies created by experimental adult removals. Limited breeding habitat and territorial behavior of older birds thus appear to be the main causes of delayed breeding in kingbirds. The frequency of delayed breeding in most species is unknown but of potential significance because failure to incorporate accurate estimates of age at first reproduction in population models may lead to flawed population projections.
The Auk, 2004
Oћђ ќѓ ѡѕђ most fundamental discoveries in behavioral ecology has been the importance of variation in individual quality. From sexual selection (Andersson 1994) to foraging (Grant and Grant 2002) and life histories (Kruuk et al. 2002), phenotypic variation can have important eff ects on fi tness of individuals and those with which they interact. For example, in lifehistory studies, ecologists have oĞ en observed that individuals that produce more off spring also survive at a higher rate (Smith 1981, Verhulst and Tinbergen 1991). Instead of questioning the existence of fundamental trade-off s in life-history allocation, most researchers have aĴ ributed those positive correlations to nonheritable phenotypic quality variations that overwhelm underlying genetic trade-off s (Partridge and Harvey 1985). If those individual quality diff erences are AяѠѡџюѐѡ.-In many avian species, including Tree Swallows (Tachycineta bicolor), females that lay eggs earlier in the season have higher fi tness. It has been hypothesized that nonheritable variation in individual quality could explain how variation in laying date persists in the face of this apparently directional selection. Previous experimental work on Tree Swallows has suggested that natural variation in fl ight ability enables early-laying females to aĴ ain feeding rates high enough to support egg production on earlier, sparser food than later-laying females. We tested that hypothesis with standardized fl ights through a 9.75-m fl ight-performance test tunnel. One group of female swallows was tested at the height of the breeding season on 28 May regardless of their nesting phenology; another group was tested on the 11th day of incubation. Average acceleration in the tunnel was negatively correlated with clutch initiation date for the females tested on 28 May. Daily variation in ambient environmental conditions had strong eff ects on swallow fl ight performance in the tunnel, and no relationship was observed in the day-11 birds. Because natural variation in foraging performance is correlated with variation in female Tree Swallows' clutch initiation dates, fl ight ability appears to be a key element of individual quality in this species.