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José Antonio

Bio: José Antonio is an academic researcher. The author has contributed to research in topics: Bonelli's eagle & Hieraaetus. The author has an hindex of 1, co-authored 1 publications receiving 10 citations.

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01 Jan 2007
TL;DR: The diet of non-breeding period has proved to influence the healthy of birds, body condition and the reproductive output in the subsequent breeding attempt as mentioned in this paper, leading to a strong limitation of both density and survival of a number of bird species.
Abstract: raptors remains largely unknown since most of diet studies are usually restricted to a half of the year, the breeding season, probably due to the easiness for recovering food data related to the association of individuals to nesting sites. Contrary, during the non-breeding season birds are difficult to locate and information on diet is scarce, causing lack in overall knowledge and comprehension of feeding habits (Cramp and Simmons, 1980; del Hoyo et al., 1994; Ferguson-Lees and Christie, 2001). Because of food is one of the main limiting factors for birds of prey (Newton, 1979), this shortage in basic information during a long life-period of such species should be urgently addressed. In this sense, the diet of nonbreeding period have proved to influence the healthy of birds, body condition and the reproductive output in the subsequent breeding attempt (Newton, 1979; Gonzalez, 1991), finally leading to a strong limitation of both density and survival of a number of bird species (see a review in Newton, 1998). Hence the study on non-breeding diet in raptors, a group of species usually threatened (del Hoyo et al., 1994; Tucker and Heath, 1994), is not only an important aspect to promote the ecology knowledge but also a necessary tool to plan adequately conservation measures. The Bonelli s eagle Hieraaetus fasciatus is an endangered bird of prey (Tucker and Heath, 1994; Real, 2004) inhabiting the Mediterranean coast, Middle East and southern Asia (del Hoyo et al., 1994; Ferguson-Lees and Christie, 2001). Dietary studies on this species are frequently related to the breeding season and restricted around European continent (Jordano, 1981; Palma et al., 1984; Fernandez and Insausti, 1986; Real, 1987; Salvo, 1988; Simeon and Wilhelm, 1988; Rico et al., 1990; Real, 1991; Gil-Sanchez et al., 1994; Leiva et al., 1994; NON-BREEDING FEEDING ECOLOGY OF TERRITORIAL BONELLI S EAGLES HIERAAETUS FASCIATUS IN THE IBERIAN PENINSULA

10 citations


Cited by
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Journal ArticleDOI
01 Jan 2010-Ibis
TL;DR: Bonelli's Eagle Aquila fasciata is one of the rarest birds of prey in Europe, where it has suffered a significant decline in recent decades as discussed by the authors, and the home ranges and spatial parameters of 18 Bonelli's Eagles radiotracked in 2002-2006 in Catalonia (northeast Spain) and describe the home-range probability kernel, distances moved, breeding area eccentricity, territorial overlap, nearest neighbour distance and breeding site fidelity.
Abstract: Bonelli’s Eagle Aquila fasciata is one of the rarest birds of prey in Europe, where it has suffered a significant decline in recent decades. We present information on the homeranges and spatial parameters of 18 Bonelli’s Eagles radiotracked in 2002–2006 in Catalonia (northeast Spain) and describe the home-range probability kernel, distances moved, breeding area eccentricity, territorial overlap, nearest neighbour distance and breeding site fidelity, and assess the influence of sex, breeding status, season and geographical area on these parameters. Median home-range according to the minimum convex polygon (MCP) and 95% kernel were 50.3 and 36.1 km 2 , respectively. The median breeding area eccentricity was 1477 m. There was considerable overlap in the home-range of both sexes within pairs (MCP: 71.4% and 95% kernel: 98.5%), indicating close pair bonding and similar foraging patterns. Overlap in home-ranges of up to 15% between neighbouring individuals also occurred and was positively related to breeding pair density. There was no difference in spatial parameters between sexes or with breeding status, but during the non-breeding season Eagles had larger home-ranges and stayed further from nests. The high consistency across birds suggests a pattern of spatial use that is characteristic of this species. The high level of use of breeding areas and their surroundings (50% kernel) throughout the year makes it important that these areas be protected from human disturbance. Additionally, it is necessary that heavily used areas away from nesting sites, which are used for foraging and roosting, are identified, protected and managed in a sustainable fashion.

72 citations

Journal ArticleDOI
TL;DR: It is suggested that pellet and prey remains analyses under‐represent the role of carrion in the diet of avian predators in Mediterranean ecosystems.
Abstract: Capsule Golden Eagles consumed more carrion than shown by traditional analyses. Aims To determine whether the traditional methods for diet determination in avian predators are subject to biases in relation to the consumption of carrion. Methods The consumption by Golden Eagles of ungulate carcasses supplied through sport hunting in a typical Mediterranean area of southeast Spain was monitored by camera trapping through an entire year. We simultaneously analysed the breeding diet of three Eagle pairs by conventional procedures. Results Golden Eagles regularly used ungulate carrion in the study area, benefiting from 57% of the available carcasses. Ninety percent of the territorial eagles fed on monitored carcasses, and the consumption was similar through the year. However, this source of food comprised only 1.5–9.1% of the prey items identified by traditional methods. Conclusions Our findings suggest that pellet and prey remains analyses under‐represent the role of carrion in the diet of avian predators in ...

41 citations

Journal ArticleDOI
TL;DR: Type II, non-regulatory, functional responses (typical of specialist predators) offered the best fitting models for both prey and, in the absence of a numerical response, Bonelli’s eagle role as a regulating factor of rabbit and partridge populations seems to be weak in this study area.
Abstract: How predators impact on prey population dynamics is still an unsolved issue for most wild predator–prey communities. When considering vertebrates, important concerns constrain a comprehensive understanding of the functioning of predator–prey relationships worldwide; e.g. studies simultaneously quantifying ‘functional’ and ‘numerical responses’ (i.e., the ‘total response’) are rare. The functional, the numerical, and the resulting total response (i.e., how the predator per capita intake, the population of predators and the total of prey eaten by the total predators vary with prey densities) are fundamental as they reveal the predator’s ability to regulate prey population dynamics. Here, we used a multi-spatio-temporal scale approach to simultaneously explore the functional and numerical responses of a territorial predator (Bonelli’s eagle Hieraaetus fasciatus) to its two main prey species (the rabbit Oryctolagus cuniculus and the red-legged partridge Alectoris rufa) during the breeding period in a Mediterranean system of south Spain. Bonelli’s eagle responded functionally, but not numerically, to rabbit/partridge density changes. Type II, non-regulatory, functional responses (typical of specialist predators) offered the best fitting models for both prey. In the absence of a numerical response, Bonelli’s eagle role as a regulating factor of rabbit and partridge populations seems to be weak in our study area. Simple (prey density-dependent) functional response models may well describe the short-term variation in a territorial predator’s consumption rate in complex ecosystems.

39 citations

Journal ArticleDOI
TL;DR: The use of digital trail cameras are recommended as an efficient, non-intrusive method to study the diet of cliff-nesting raptors, given that, in combination with traditional methods, it facilitates estimation of dietary composition in an objective, economic, contrastable and unbiased manner.
Abstract: The study of avian diet is one of the most commonly discussed topics in Ornithology. Different methods such as direct observations of hunting, analysis of pellets and collection of prey remains have usually been employed to study avian diet. Fortunately, digital technologies have rapidly advanced in recent years, allowing researchers to increase our understanding of avian behaviour. Here we report the outcomes of a pilot project to study the diet of Bonelli's eagle (Aquila fasciata, Syn = Hieraaetus fasciatus) during the nestling period using digital trail cameras. We describe the monitoring system, provide results on dietary composition and discuss advantages and shortcomings of the method employed. Our results show that the main prey delivered to nests were pigeons (Columba spp.) and common rabbits (Oryctolagus cuniculus). One advantage of the method is the relative low cost of the material employed in contrast to digital video cameras. Disadvantages were the limited duration of power supply of...

17 citations