What do we know about survival of Common cranes? An elementary introduction with Euring databank

Abstract

The increase of the western populations of Common cranes (Grus grus) in the last five decades highlights the need to estimate survival rates. According to Euring databank (EDB), the oldest Common crane ever known was 27 years old in year 2017. This lifespan was obtained by means of 24,900 recoveries of 2,124 ringed cranes collected between years 1936 and 2017. Nearly all cranes were ringed and observed in the last 30 years, and therefore the elapsed time was not enough to reach the maximum longevity reported for the species in captivity (43 years, Mitchell 1911). Life expectancy was five years on average after the ring was attached. Here we provide some elementary analyses to calculate the annual apparent survival rate ({phi} = 0.85) and the annual encounter probability (p = 0.45) of Common cranes, as a first step to advance in the knowledge of the species population dynamics. The great increase of breeding and wintering crane populations in western Europe in the last decades remains largely unexplained.