Nest use, interspecific relationships and competition for nests in the Bearded Vulture<i>Gypaetus barbatus</i>in the Pyrenees: influence on breeding success

Margalida, Antoni; Garcia, Diego Azevedo Zoccal

doi:10.1080/00063659909461134

Cited by 25 publications

(16 citation statements)

References 9 publications

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“…Despite the potential for interspecific nest-site competition, the breeding success of Bonelli's Eagle pairs was not affected by nest competition, due to the existence of multiple nests. Similarly, although 40% of bearded vulture Gypaetus barbatus nests in the Pyrenees (a rugged area of northern Spain with high nest-site availability) were usurped by other species, this did not influence the breeding success of this cliff-nesting raptor (Margalida and García 1999).…”

Section: Discussionmentioning

confidence: 89%

Possible functions of alternative nests in raptors: the case of Bonelli’s Eagle

2008

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Four non-exclusive hypotheses have been proposed to explain the alternative nest-building behaviour of raptors: (1) nests as an advertising signal in territories, (2) frustration nests, (3) competition avoidance by nest-site and (4) reduction of nest ectoparasites. We report here data collected during an observational study of a population of Bonelli's Eagle Hieraaetus fasciatus in southeastern Spain. Our data does not support the first two hypotheses based on the closeness of nests within territories, the lack of correlation between the number of nests and the distance to neighbours and the construction of secondary nests at similar frequencies after breeding failures as after successes. In contrast, the construction of alternative nests to avoid competition with other cliff-nesting raptor species breeding nearby was clearly important since 30% of the pairs obtained some direct benefit from the existence of alternative nests within their territories. We also found abundant Coleoptera (Dermestidae) and Diptera (Carnidae, Calliphoridae and Phoridae) as ectoparasites in nests, and the alternative use of nests, synergetically with the presence of greenery as mechanisms for avoiding ectoparasites, was an important factor for the breeding success of the eagle. Our data suggest that competition avoidance and, in particular, the reduction of nest ectoparasite hypotheses are the more plausible explanations for the maintenance of alternative nests in raptors.

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Section: Discussionmentioning

confidence: 89%

Possible functions of alternative nests in raptors: the case of Bonelli’s Eagle

2008

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“…This is suggested by the significant increase in failures during hatching and in the first days of chick‐rearing and the possible temporal variability in the diet during this period (Margalida & Bertran 1997, Margalida & Bertran 2001). Interspecific interactions : in the study area 40% ( n = 70) of Bearded Vulture nests were usurped by other species, principally Griffon Vultures ( Gyps fulvus ) (81% of the nests: Margalida & García 1999, see also Bertran & Margalida 2002b). Such expulsions may have a greater effect on those territories situated at high altitude more exposed to rigorous climatic conditions; furthermore, with limited alternatives for resiting, nests could be relocated with greater exposure to humans or unfavourable environmental conditions (Margalida & García 1999).…”

Section: Discussionmentioning

confidence: 99%

“…1997), density‐dependent effects (Fernández et al . 1998), predation (Houston 1976, Brown 1990), interspecific interactions (Margalida & García 1999) and human disturbance (Donázar et al . 1993).…”

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confidence: 99%

Breeding biology and success of the Bearded Vulture Gypaetus barbatus in the eastern Pyrenees

Margalida¹,

Garcia

Bertran³

et al. 2003

Ibis

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We present data from an extensive study of Bearded Vulture Gypaetus barbatus breeding biology in the Pyrenees from 1992 to 1999. Average laying date was 6 January (range 11 December to 12 February, n = 69) with no significant differences between years. Eighty per cent of clutches were of two eggs ( n = 20) and average incubation was 54 days (range 52-56, n = 14). Hatching occurred on average between 21 February and 3 March (range 5 February-7 April) and the first and last chicks fledged in 21-27 May and 20 July, respectively. The average chick age at fledging was 123 days (range 103-133, n = 20). Bearded Vulture density increased significantly during the study period. Breeding success and productivity declined apparently as a consequence of the increase in the percentage of breeding failures during incubation and chick rearing, most during the hatching period. The factors that may determine breeding failure and the decline in breeding performance are analysed and management recommendations for more effective conservation measures are discussed.

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“…North-west and south-east aspect preferences shown by bearded vultures may be accounted for by wind patterns or interspecific competition with other cliff nesters, especially golden eagles Aquila chrysaetos and Eurasian griffons (Fernandez & Don´azar, 1991;Margalida & Garcia, 1999), and this may influence aspect choice.…”

Section: Nest-site Characteristicsmentioning

confidence: 98%

Breeding site selection by bearded vulture (Gypaetus barbatus) and Eurasian griffon (Gyps fulvus) in the Caucasus

Gavashelishvili¹,

McGrady²

2006

Animal Conservation

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Occupied and unoccupied sites of bearded vulture Gypaetus barbatus and Eurasian griffon Gyps fulvus were located in the Caucasus (mainly Georgia). Habitat variables related to nest-site characteristics, climate, terrain, human disturbance and food availability were used to construct predictive models of vulture breeding site selection by using a geographic information system (GIS), logistic regression and Bayesian statistical inference. The probability of bearded vulture occupancy of a cliff ledge that was safe from climatic adversity, human disturbance and predation was positively correlated with the following variables measured within a 20-km radius of the ledge: mean elevation, mean slope, the percentage of open areas, mean distance to roads, number of globally threatened wild goats Capra cylindricornis, C. caucasica and C. aegargus, and annual biomass of dead livestock. The probability of such a cliff ledge being occupied by Eurasian griffon was negatively correlated with annual rainfall at the ledge and positively correlated with the percentage of open areas and annual biomass of dead livestock within 20 km of the ledge. Provided that GIS coverage of the habitat variables is available, these models can be of help in various areas of the Caucasus and elsewhere to predict possible nest occurrence areas, and highlight sites where vultures may occur in the future if the population grows because of conservation or other activities.

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Nest use, interspecific relationships and competition for nests in the Bearded VultureGypaetus barbatusin the Pyrenees: influence on breeding success

Cited by 25 publications

References 9 publications

Possible functions of alternative nests in raptors: the case of Bonelli’s Eagle

Possible functions of alternative nests in raptors: the case of Bonelli’s Eagle

Breeding biology and success of the Bearded Vulture Gypaetus barbatus in the eastern Pyrenees

Breeding site selection by bearded vulture (Gypaetus barbatus) and Eurasian griffon (Gyps fulvus) in the Caucasus

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