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Whether predators can limit their prey has been a topic of scientific debate for decades. Traditionally it was believed that predators take only wounded, sick, old or otherwise low-quality individuals, and thus have little impact on prey populations. However, there is increasing evidence that, at least under certain circumstances, vertebrate predators may(More)
Research conducted in several Mediterranean areas indicates that most populations of steppe birds are currently experiencing population declines associated with intensification of traditional agricultural practices. By using habitat suitability modeling (HSM), our aim was to use available environmental data sets, including land use and relief, to model the(More)
During 1980-97, trichomoniasis was detected in nestlings of Bonelli's eagle Hieraaetus fasciatus in Catalonia (Spain). In 1993 Trichomonas gallinae was isolated in 36% of nestlings (n = 39) and affected 41% of broods (n = 22). Overall, trichomoniasis was one of the most important single nestling mortality factor, accounting for 22% of total chick mortality,(More)
Data on 10-y of chemical toxicological analyses carried out in a veterinary laboratory in Barcelona, Spain for suspected wild and domestic animal poisonings are summarized. The 218 cases involved more than 1 million animals, some 7,500 of which died. Pesticides, especially insecticides (46.6%) and rodenticides (37.9%), were frequently involved. Strychnine(More)
The Ebro delta (NE Spain) is a 320 km2 wetland area of international importance for conservation. The area is devoted to rice farming and receives large amounts of pesticides. Industrial pollutants are also carried to the delta by the river. The information accumulated during the last 25 year on the effect of such pollution on the biota is reviewed in order(More)
Persistent organochlorine compounds (pesticides and polychlorinated biphenyls) were determined in 24 northern goshawk (Accipiter gentilis) and eight Eurasian buzzard (Buteo buteo) samples of eggs collected between 1988 and 1999 in La Segarra (northeast Spain), in order to evaluate the changes in exposure and detrimental effects during this period. In the(More)
Four little bustards (Tetrax tetrax) (one adult and three juvenile males), captured with leg nooses and fitted with a backpack radiotag, died after capture. The first bird was found after 16 days with its left foot caught in the harness and died after 1 day. The other birds showed symptoms of capture myopathy after release, such as the difficulty or(More)
In response to climate changes that have occurred during Pleistocene glacial cycles, taxa associated to steppe vegetation might have followed a pattern of historical evolution in which isolation and fragmentation of populations occurred during the short interglacials and expansion events occurred during the long glacial periods, in contrast to the pattern(More)
The presence of conspecifics can strongly modulate the quality of a breeding site. Both positive and negative effects of conspecifics can act on the same individuals, with the final balance between its costs and benefits depending on individual characteristics. A particular case of inter-individual variation found in many avian species is chromatic(More)
Bird electrocution rates in Secanos de Lérida, an important bird area in central Catalonia (northeast Spain), were estimated based on 804 visits to 507 electric pylons between 1995 and 1999. Electrocution caused a minimum of 160 victims on 67 pylons. Victims were corvids (36%), diurnal birds of prey (60%) and owls (4%). Electrocution rates ranged between(More)