2002: Population size and factors affecting the density of the peregrine falcon Falco peregrinus in Spain
SUMMARY.-Population size and factors affecting the density of the Peregrine Falcon Falco peregrinus in Spain. By means of bibliographical searches and requests of unpublished information from ornithologists and public administrations all over the country, the population size estimate of the Peregrin...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1054.9970 http://www.avibirds.com/pdf/S/Slechtvalk3.pdf |
| Summary: | SUMMARY.-Population size and factors affecting the density of the Peregrine Falcon Falco peregrinus in Spain. By means of bibliographical searches and requests of unpublished information from ornithologists and public administrations all over the country, the population size estimate of the Peregrine Falcon Falco peregrinus in Spain is updated. The Spanish population is estimated at 2435-2743 pairs, which represents a mean density of 5.1 pairs/1000 km 2 and increases in 50% the previous estimate. The Peregrine Falcon is more abundant in the regions with limestone substrate in the north and east of the country, whereas its density reaches the lowest level in the southwest quadrant, an area with few cliffs and good densities of potential competitors like the Bonelli's Eagle Hieraaetus fasciatus and the Eagle Owl Bubo bubo. In order to know the factors that could influence the species density, a multiple regression analysis was carried out with data from provinces with specific censuses or local atlases with good coverage. The resulting equation explained 68.67% of the total variance and included three predicting variables: type of geological substrate, length of seacliffs and latitude. This equation was used to check the reliability of the population estimates from provinces with poor quality data as well as to calculate the expected density in the two provinces for which only partial data were available. Overall, the recent trend of the Spanish population appears to be positive, although in several regions the species shows a downward trend attributable to the incidence of pesticides, nest-robbing and competence with the Eagle Owl. Key words: Density, environmental variables, Falco peregrinus, Peregrine Falcon, population size, Spain, threats. RESUMEN.-Tamaño de población y factores que afectan la densidad del Halcón Peregrino Falco peregrinus in Spain. Mediante una revisión de la bibliografía y consultas a ornitólogos y administraciones públi-cas de todo el país, se actualizó la estimación de la cuantía de la ... |
|---|