1) to study the basic demographic parameters of adult breeders (age of recruitment, breeding success and adult survival) in relation to sex and age.
Since the parental roles of Egyptian vultures are roughly similar between sexes (see below), we expect similar parameters for males and females and/or age related improvements early in life (through acquisition of skills and experience or the (dis)appearance of different quality phenotypes) and/or late-in-life deteriorations due to senescence. Regarding variations in breeding success with age, a first mixed modeling approach showed a tendency of Egyptian vultures to experience a higher probability of breeding successfully with the logarithm of age (estimate ± SE = 2.575 ± 1.013, Chi-square = 6.46, p = 0.001).
However, recent studies on long-lived birds indicate a very late life senescence (e.g.
refs 8 and 9, which could also be masked by the selective disappearance of certain phenotypes among the older age-classes may be responsible for sex-biased survival. wrote the manuscript and other authors provided comments and editorial advice.
We evaluate the combined effects of age and sex in recruitment, breeder survival and breeding success of the globally endangered Egyptian vulture (Neophron percnopterus), using 31-years of exhaustive data on marked individuals in Spain.
Mean age of first reproduction was 7-yrs for both sexes, but females showed an earlier median and a larger variance than males.
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In long-lived species, the age-, stage- and/or sex-dependent patterns of survival and reproduction determine the evolution of life history strategies, the shape of the reproductive value, and ultimately population dynamics.Female and male Egyptian vultures showed a median age of first reproduction of 6 and 7 yrs, respectively (Fig. Mean age of first reproduction was similar (6.88 yrs in females and 7.25 yrs in males, t = −0.645, DF = 39.243, p = 0.523) but the variance was significantly larger among females that among males (ranges: 3–14 yrs vs. In a second step, the within-subject centering method indicated that this increase in performance with age was due to the selective appearance and disappearance of certain individuals, being similar for both sexes, and not to improvement within individuals as they aged (Table 1). Importantly, age of first and last reproduction were positively correlated (rs = 0.76, p 0.99). They begin to show hair a few days after birth, and their eyes and ears are open by day 10.Newborn rabbits are unable to regulate their own body temperature until about day 7. Most people raising rabbits for show or as pets rebreed 35 to 42 days after the birth of a litter.This is not an indication of a security issue such as a virus or attack.