Abt K. & Konter A. (2009) Survival rates of adult European grebes (Podicipedidae). ARDEA 97 (3): 313-321

Ring recoveries of dead individuals from all over Europe and covering a period of 57 years were collected to study survival of Great Crested Podiceps cristatus (n = 433), Black-necked P. nigricollis (n = 95) and Little Grebes Tachybaptus ruficollis (n = 295). Survival rates of adult birds were estimated by fitting simple mark–recapture models via maximum-likelihood. Realizing that the samples were extremely heterogeneous and possibly biased, it was further investigated how the survival data conformed to information from literature on fledging success, age at first breeding, and long-term population trends. In the Great Crested Grebe, ring recoveries were biased towards young birds, as indicated by a marked, untypical increase in apparent survival after the age of 3 years. Also, the whole-sample estimate of 0.66 was too low to match the other demographic parameters. The survival rate of 0.75 (95% CI 0.69–0.80) estimated for birds of 4 years and older conformed well with the breeding performance established for Great Crested Grebes and is thus considered as a realistic estimate for adult birds. The survival rate estimate of 0.63 (95% CI 0.55–0.70) for the Black-necked Grebe seemed a slight underestimate given estimates for the other demographic parameters. Apart from a possible, albeit undetected, sample bias towards younger birds, some influence of ring loss cannot be excluded, because in contrast to the other two species, the Black-necked Grebe sample contained a high proportion of aluminium rings. The survival rate of Little Grebe was estimated at 0.60 (95% CI: 0.55–0.64), which corresponded well with other demographic data.