| Summary: | Estimation of trade-offs between current reproduction and future survival and fecundity of long-lived vertebrates is essential to understanding factors that shape optimal reproductive investment. Black brant geese (Branta bernicla nigricans) are able fledge more goslings, on average, when their broods are experimentally enlarged to be greater than the most common clutch size of four eggs. Thus, we hypothesized that the lesser frequency of brant clutches exceeding four eggs results, at least partially, from a future reduction in survival, breeding probability, or clutch size for females tending larger broods. We used an eight-year mark-recapture dataset (Barker robust design) with five years of clutch and brood manipulations to estimate long-term consequences of reproductive decisions in brant. We did not find evidence of a trade-off between reproductive effort and true survival or future clutch size. Rather, future breeding probability was maximized (0.92 ± 0.03 [se]) for manipulated females tending broods of four goslings (i.e., the most common natural brood size) and lower for females tending smaller (one gosling; 0.63 ± 0.09 [se]) or larger broods (seven goslings; 0.52 ± 0.15 [se]). Our results suggest that demographic trade-offs for female brant tending large broods may reduce the fitness value of clutches larger than four and, therefore, contribute to the paucity of larger clutches. The lack of a trade-off between reproductive effort and survival provides evidence that this trait, to which fitness is most sensitive in long-lived animals, is buffered against temporal variation. cs_initiation_dateThis file contains data used to estimate the effects of clutch and brood size manipulations on clutch size and initiation date of female black brant in year t+1. Variable descriptions are as follows: "METAL" is the unique number on a female's steel leg band; "CSM1" is the laid clutch size of a female in year t -1; "CS" is the laid clutch size of a female in year t. "IDM1" is the initiation date, in Julian days, of ...
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