José A. Donázar

CAUSES AND CONSEQUENCES OF TERRITORY CHANGE AND BREEDING DISPERSAL DISTANCE IN THE BLACK KITE

Factors affecting individual variation in between-year territory change and dispersal distance were measured in a long-term study of Black Kites (Milvus migrans) living in an area of ∼100000 ha in and around Donana National Park in southern Spain. Adult birds (N = 210) and fledglings (N = 3061) were individually marked, and breeding birds were monitored annually during 1989–1996 to detect banded individuals. Of these 3271 birds, 652 breeding birds were resighted, and 164 of them were sexed through copulatory behavior. Nests were checked annually to monitor breeding performance. Frequencies of return between years were 83.1% for breeding males and 89.5% for breeding females. Frequencies of territory change were 25.6% and 32.8%, respectively. Females >8 yr old rarely changed territories. Dispersing birds departed significantly more from low-quality territories (evaluated through breeding success variables). Breeding failure and mate loss (divorce or death) favored breeding dispersion, both in males and fema...

Factors Influencing Nest Site Selection, Breeding Density and Breeding Success in the Bearded Vulture (Gypaetus barbatus)

We examined the nest site selection, breeding density and breeding success in the bearded vulture Gypaetus barbatus in relation to physiography, climate, land-use and degree of human disturbance. The study area was in the Pyrenean Cordillera, Spain, where the largest European population of this species occurs. univariate analyses and Generalized Linear Models were employed. Models correctly classified the 78% of the cliffs analysed (occupied by bearded vultures, and selected at random). The probability of occupation of a cliff by bearded vultures was directly related to the ruggedness of the topography, altitude, distance to the nearest bearded vulture occupied nest, and distance to the nearest village

Testing the Goodness of Supplementary Feeding to Enhance Population Viability in an Endangered Vulture

Background Human-predator conflicts are directly or indirectly threatening many species with extinction. Thus, biologists are urged to find simple solutions to complex situations while avoiding unforeseen conservation outcomes. The provision of supplementary food at artificial feeding sites (AFS) is frequently used in the conservation of scavenger bird populations currently suffering from indirect poisoning, although no scientific studies on its effectiveness have been conducted. Methodology/Principal Findings We used a long-term data set of 95 individually marked birds from the largest European core of the endangered bearded vulture (Gypaetus barbatus) to test the long-term effects of specific AFS for bearded vultures on their survival rates (by CMR models) and population dynamics (by Monte Carlo simulations) in an area where fatalities derived from illegal poisoning and the use of other toxics like veterinary drugs have increased over the last several years. Our data support the positive relationship between the use of AFS and survival. However, contrary to theoretical predictions (e.g. high and more stable adult survival among long-lived species), the use of AFS increased only survival of pre-adults. Moreover, AFS buffered the effects of illegal poisoning on this age-class, while adult survival decreased over years. Our simulations predicted a maximum value of extinction probability over a time horizon of 50 years. Population projections run with survival rates expected in scenarios without poisoning predicted the situation of least conservation concern, while including only AFS can maintain a large floater surplus that may delay population decline but fails to reduce poisoning risk among adults. Conclusions/Significance Although AFS are not effective to save bearded vultures from an expected population decline, they delay population extinction and can be a useful tool for prolonging population viability while combating illegal and indirect poisoning. The eradication of different sources of poisoning is of top priority to ensure the long-term viability of this and many other species.

CAUSES AND FITNESS CONSEQUENCES OF NATAL DISPERSAL IN A POPULATION OF BLACK KITES

Natal dispersal is of central interest when determining demography and genetic structure of populations and managing endangered species with fragmented distributions. However, methodological limitations linked to spatial and temporal constraints have prevented studies of natal dispersal in long-lived birds. Moreover, the consequences of natal dispersal have mainly been related to the first breeding attempt rather than to lifetime reproductive success. We studied the causes and fitness consequences of natal dispersal in a population of Black Kites at Donana National Park (southern Spain). From 1986 to 1995 we marked 2929 nestlings with plastic numbered bands. We annually monitored marked birds in breeding territories, their breeding success, and the survival of nonbreeding birds. Additionally, we searched for marked birds in broad areas of the Iberian Peninsula and North Africa. Median natal dispersal distance was 4.8 km (N = 285), with males more often dispersing shorter distances and females dispersing at all distance categories equally. Density of conspecifics negatively affected dispersal distances of both males and females. In addition, single and first-hatched males born in areas with high breeding density dispersed shorter distances. Dispersal distances tended to be correlated between siblings, possibly a result of sharing similar environmental conditions. We did not find evidence that dispersal was an active mechanism aimed to prevent close inbreeding. Patterns of dispersal in this population are probably driven by intraspecific competition. Males that dispersed shorter distances showed higher lifetime reproductive success (LRS). LRS did not differ among females dispersing different distances, but females that dispersed farther mated with more experienced males. These sex differences in dispersal patterns and their consequences may be explained by the inequality between sexes in breeding roles in this species. Familiarity with the natal area could be important for males, which defend territories and resources, while females may increase their fitness through mate choice and breeding dispersal. High levels of philopatry in Donana National Park may be a result of a surplus of food resources and the effects of conspecific attraction in densely populated areas. However, the degree of philopatry may vary between populations and with time, subject to differences in ecological pressures.

Long-term effects of lead poisoning on bone mineralization in vultures exposed to ammunition sources

Long-lived species are particularly susceptible to bioaccumulation of lead in bone tissues. In this paper we gain insights into the sublethal effects of lead contamination on Egyptian vultures (Neophron percnopterus). Our approach was done on the comparison of two populations (Canary Islands and Iberian Peninsula) differing in exposures to the ingestion of lead ammunition. Blood lead levels were higher in the island population (Canary Islands range: 5.10-1780 microg L(-1) n=137; Iberian Peninsula range: 5.60-217.30 microg L(-1) n=32) showing clear seasonal trends, peaking during the hunting season. Moreover, males were more susceptible to lead accumulation than females. Bone lead concentration increased with age, reflecting a bioaccumulation effect. The bone composition was significatively altered by this contaminant: the mineralization degree decreased as lead concentration levels increased. These results demonstrate the existence of long-term effects of lead poisoning, which may be of importance in the declines of threatened populations of long-lived species exposed to this contaminant.

DISPERSAL AND SOCIAL ATTRACTION AFFECT COLONY SELECTION AND DYNAMICS OF LESSER KESTRELS

We studied the mechanisms that regulate colony dynamics in a Spanish population of Lesser Kestrels, using eight years of data from banded individuals in 494 colony-years. Colony growth was positively related to breeding success at the colony the year before. However, individuals of all dispersal statuses, i.e., adult and first-breeding philopatric and immigrant birds, significantly contributed to changes in colony size, indi- cating an important effect of dispersal on colony dynamics via colony quality. Given that there is strong evidence that Lesser Kestrels base their settlement decisions on conspecifics, we tested whether immigrants used the number of previously settled residents in year t (social or conspecific attraction hypothesis) and/or the breeding performance of conspecifics in year t 2 1 (performance-based attraction hypothesis) to select their breeding colony. Breeding success of colonies varied both in space and time and was autocorrelated from one year to the next. Moreover, lifetime reproductive success of Lesser Kestrels was pos- itively associated with colony size, and individuals can predict final colony size early in the breeding season, so assumptions of both hypotheses were fulfilled. Our results support the social attraction hypothesis, since immigration was positively related to the number of philopatric adults, but not to conspecific breeding success the year before. Given that departure decisions of adults were based on personal information about breeding success and colony size is related to fitness prospects, previously settled individuals provide easy and reliable information about colony quality, and social attraction could be seen as a particular case of public information in Lesser Kestrels. Consistently, absolute numbers of both philopatric adults and immigrants increased with colony size the year before, although immigrants increased only up to a threshold beyond which this trend disappeared. Therefore, immigrants seem to be prevented from settling in the largest colonies, which could explain why all individuals do not concentrate in a few big colonies, but some settle in suboptimal colonies or colonize unoccupied sites. This opposing effect of conspecifics, together with the low levels of temporal autocorrelation in colony quality between time lags

Phylogeography, genetic structure and diversity in the endangered bearded vulture (Gypaetus barbatus, L.) as revealed by mitochondrial DNA

2 yr, could promote colony size variability and facultative coloniality in this species.

Too sanitary for vultures.

Bearded vulture populations in the Western Palearctic have experienced a severe decline during the last two centuries that has led to the near extinction of the species in Europe. In this study we analyse the sequence variation at the mitochondrial control region throughout the species range to infer its recent evolutionary history and to evaluate the current genetic status of the species. This study became possible through the extensive use of museum specimens to study populations now extinct. Phylogenetic analysis revealed the existence of two divergent mitochondrial lineages, lineage A occurring mainly in Western European populations and lineage B in African, Eastern European and Central Asian populations. The relative frequencies of haplotypes belonging to each lineage in the different populations show a steep East–West clinal distribution with maximal mixture of the two lineages in the Alps and Greece populations. A genealogical signature for population growth was found for lineage B, but not for lineage A; futhermore the Clade B haplotypes in western populations and clade A haplo‐types in eastern populations are recently derived, as revealed by their peripheral location in median‐joining haplotype networks. This phylogeographical pattern suggests allopatric differentiation of the two lineages in separate Mediterranean and African or Asian glacial refugia, followed by range expansion from the latter leading to two secondary contact suture zones in Central Europe and North Africa. High levels of among‐population differentiation were observed, although these were not correlated with geographical distance. Due to the marked genetic structure, extinction of Central European populations in the last century re‐sulted in the loss of a major portion of the genetic diversity of the species. We also found direct evidence for the effect of drift altering the genetic composition of the remnant Pyrenean population after the demographic bottleneck of the last century. Our results argue for the management of the species as a single population, given the apparent ecological exchangeability of extant stocks, and support the ongoing reintroduction of mixed ancestry birds in the Alps and planned reintroductions in Southern Spain.

Conservation status and limiting factors in the endangered population of Egyptian vulture (Neophron percnopterus) in the Canary Islands

The current crisis of biodiversity has hit old-world vultures especially hard; populations that flourished in the mid-20th century over much of Asia and Africa are in some cases close to extinction ([ 1 ][1]). In Europe, however, vultures have been spared, and today the Mediterranean basin is home

Offspring body condition and immunocompetence are negatively affected by high breeding densities in a colonial seabird: a multiscale approach

Egyptian vulture populations have decreased sharply in the Western Palearctic; island populations are almost extinct in the Mediterranean and the Macaronesian regions. In the Canary archipelago, the species only survives in the islands of Fuerteventura and Lanzarote. During 1998–2001 we examined population parameters and evaluated some potential limiting factors for this isolated and sedentary population. The total population (breeding and non-breeding birds) was monitored annually. In addition, 26 fledglings and 33 immatures ( 6 years old birds) and immature annual survival rates were similar, around 90%. Adult survival was lower than expected as territorial birds seem more susceptible to poisoning. Immature survival could be favoured by the existence of regular feeding places. Casualties from power lines was the main cause of mortality (12 cases during the study period). Blood sampling revealed high frequencies of lead poisoning: 13.5 and 2.7% of individuals showed sub-clinical and clinical intoxication levels, respectively, probably caused by the ingestion of lead shot. Priority conservation measures should be directed to reduce electrocution risks, illegal poisoning, and lead contamination. Population reinforcement with birds coming from other populations is not recommended as previous information reveals morphological and genetic differentiation of Canarian Egyptian vultures compared with continental populations. # 2002 Elsevier Science Ltd. All rights reserved.