Environmental variability, life-history covariation and cohort effects in the red-billed chough Pyrrhocorax pyrrhocorax

摘要: Summary 1 The consequences of environmental variability for life-history evolution are predicted to depend on the pattern covariation amongst traits. Using data from a 20-year study individually marked red-billed choughs, we investigate short- and long-term population-wide variation in reproductive conditions, demonstrate clear among-cohort parameters. 2 The mean number offspring fledging per breeding event varied among years, was correlated with conditions (temperature rainfall) during months preceding breeding. As variance performance did not differ years choughs miss seasons, affected whole population. Thus quality chough's environment years. 3 Juvenile survival, probability recruitment population longevity cohorts, these were positively cohort's natal environment. Offspring under good more likely survive age recruit, had longer lives than poor conditions. 4 Age at first increased size maturity rather conditions. 5 The total that recruits ultimately fledged primarily age. Thus, consistent positive traits meant by their life conditions. Choughs themselves offspring. 6 Such environmentally determined fitness is expected influence optimal patterns parental investment. We discuss predictions should select investment adult survival reduced effort years.