Fig. 2.

Age-dependent mortality estimates from Gompertz models built for three different migration strategies of Greater Flamingos. Individuals can be migrants, residents, or with a mixed migratory strategy. The mortality curves from Gompertz models associated with the three migratory strategies are presented on panel A–C—the death rates m(x) (gray dots) are also presented. The posterior distribution of Gompertz model parameters are provided (D–F): basal mortality rate ($b_0$ noted in the R package BaSTA; F), actuarial senescence rate ($b_1$; E), and actuarial senescence rate corrected for lifespan (Std senescence rate; D) which was calculated by multiplying $b_1$ by life expectancy. Three adult lifespan metrics (expressed in years) were calculated using the posterior distributions of Gompertz model parameters: life expectancy, i.e., the average age at death (G); lifespan 50% (H) and 80% (I), i.e., the age at which 50% and 80% of the individuals alive at adulthood are dead. Finally, we investigated a potential trade-off between early- and late-life survival across migration strategies by examining the negative correlation between basal mortality rates $b_0$ and senescence rates $b_1$ (J)—this negative relationship is known as the “Strehler–Mildvan correlation.”