SPECIE-SPECIFIC OUTCOMES OF WILD RAPTORS ATTENDED AT A WILDLIFE REHABILITATION CENTRE IN CATALONIA (1997-2005)

Abstract

Outcome research of rehabilitation of wild birds of prey and owls are scarcely reported. The aim of this study is to investigate specie-specific outcomes of the rehabilitation practice in wild raptor attended in a wildlife center. A total of 6221 hospitalized wild raptors (3241 Strigiformes; 2980 Falconiformes) admitted at a Wildlife Rehabilitation Centre (WRC) of Catalonia from 1995 to 2007 were analysed. The outcomes indicators were based on ratios of Euthanasia (E_r), Mortality (M_r), Release (R_r) and Captivity (C_r). Stratified analyses by main causes of admission were performed for the different raptor species. Species from the Falconiformes order presented higher rates of euthanasia (33.9%) compared to the Strigiformes (18.6%). Species like B. buteo (45.7%) and M. migrans (47.6%) in the Falconiformes and B. bubo (33.6%) in the Strigiformes, presented the highest E_r. Despite no differences between orders could be observed in the row mortality rates, data analysed by the causes of admission showed that the M_r of owls was significant higher than the Falconiformes for the trauma (13.2%; χ² = 49.97; p<0.001), non trauma (12.7%; χ² = 17.41; p<0.001) and orphaned young categories (4.9%; χ² = 5.4; p = 0.02). The release rate was similar between orders. Based on species, G. fulvus (69.2%), C. aeruginosus (56.3%) and A. gentillis (43.1%) in the Falconiformes and O. scops (48.5%) in the Strigiformes showed the highest R_r. In the orphaned young category owls had better R_r than the diurnal raptors, being S. aluco the specie with the best rates of release (84%), whereas B. bubo had the worst values (50%). Specie-specific differences were found in the rehabilitation outcomes according to the different causes of admission. The stratified analysis of outcomes can be useful in order to to identify specie-specific risk factors.