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 (ϕ = 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.

High survival promotes persistence in a reintroduced population of Common Crane (Grus grus)

“…Although published survival rates are scarce and there is evidence suggesting that adult survival of wild‐reared Common Cranes is generally high (Soriano‐Redondo et al . 2019a), recent analysis using ringing data for Common Cranes across western Europe reported apparent survival at ~ 0.85, which is lower than our estimates (Bautista & Alonso 2021). Other crane species also have lower survival rates; Sandhill Cranes, for example, have considerably lower rates across various age‐classes (49.5% age 0, 79.3% age 1, 81.5% age 2, Johnsgard 1983), and some wild‐reared populations of Whooping Cranes have slightly lower adult survival when averaged across all age groups (~ 0.9; Link et al .…”

“…2014). Populations elsewhere in Europe are migratory, which may explain lower apparent survival estimates (Bautista & Alonso 2021).…”

“…In addition, Common Cranes typically undergo flightless moults every 2 years from the age of 2 (Johnsgard 1983), which is energetically costly and can leave individuals vulnerable to predation. In general our understanding of the life span of Common Cranes in the wild is lacking, although suggestions from ringing data range from 5 years (Bautista & Alonso 2021) to 14 years (Mathews & Macdonald 2001) in the wild, and up to 43 years in captivity (Mitchell 1911). However, studies of whole marked populations such as the reintroduced population discussed here will contribute to the knowledge gap concerning survival rates and longevity of this species.…”

“…French et al 2019) and avoid risks associated with long-distance movements (Klaassen et al 2014). Populations elsewhere in Europe are migratory, which may explain lower apparent survival estimates (Bautista & Alonso 2021).…”