Protected areas do not fulfil the wintering habitat needs of the trans-Saharan migratory Montagu’s harrier

Populations of migratory birds can be affected by events happening at both breeding and wintering grounds. The Sahel is a vast region holding a large number of wintering trans-Saharan migratory European birds, and current land-use changes there may represent a threat for these species. We used satellite tracking data from the migratory Montagu's harrier to evaluate habitat use of the species during the wintering season, and whether the current network of protected areas is effective to provide their habitat needs during that season. We also developed an ecological niche model for the species in Western-Central Sahel to check if the most suitable sites are included within current protected areas. Tracked harriers occupied a large region encompassing a total of eight countries. The most preferred habitats during winter were croplands and some natural vegetation habitats, especially grasslands. Protected areas only covered a small proportion of the overall wintering grounds of tracked harriers and the most suitable areas for the species in Western-Central Sahel. Increasing the extent of preferred natural habitats within protected areas should benefit the conservation of this and probably other insect-eating raptors. However, substantial increases in extent and number of protected areas in sub-Saharan Africa are very unlike to occur. Conservation actions in the region should therefore be mostly focused on improving land use planning and management outside protected areas, specially enhancing agricultural practices to make biodiversity conservation compatible with poverty alleviation. These can be chiefly targeted at an area of <20,000km 2 of very suitable habitat for these species.We are indebted to Aeropuerto de Castellón for support and funding of the project on satellite tracking of Montagu’s harriers. We are grateful to Servicio de Biodiversidad of the Conselleria de Infraestructuras, Territorio y Medio Ambiente (Generalitat Valenciana) to give the permissions to conduct this study, as well as for its collaboration in the fieldwork. R.L. has a postdoctoral grant (Reference 10/12-C) co-funded by Consejería de Educación y Ciencia (Junta de Comunidades de Castilla-La Mancha) and the European Social Fund.Peer Reviewe

Habitat use by juvenile Golden Eagles Aquila chrysaetos in Spain

Capsule Dispersing juvenile Golden Eagles are habitat generalists that do not regularly use temporary settlements. © 2008 British Trust for Ornithology.Peer Reviewe

Markov models of territory occupancy: Implications for the management and conservation of competing species

Markov chains have been frequently used in community ecology to model successional changes, but little attention has been paid to its application in population ecology as a tool to explore the outcomes of species interactions. Markov models can be regarded as >null models> that provide predicted values under a no-change scenario against which the consequences of changes in variables of interest can be assessed. Here we explore Markov chains' potential to project population trends of competing species and derive sensible management strategies. To do that we use six years of field data on territory occupancy and turn-over of two competing top predators in a Mediterranean landscape: the golden and Bonelli's eagles. The results suggest that long-term coexistence of both species in the study area is likely, with the main limitation for their coexistence being the difficulties Bonelli's eagles have in colonising new territories that become available. To avoid future declines in the population of Bonelli's eagle, it is important to take into account that the positive effects of conservation strategies focused on encouraging colonization (e.g. decreasing disperser mortality) are likely to be larger than those focused on avoiding territory abandonment (e.g. decreasing adult mortality). Markov chains are likely to be useful to evaluate the relative merit of alternative management options in other territorial species when patterns of territory occupancy are the only reliable data available, as often happens with large predators. © 2008 Springer Science+Business Media B.V.Peer Reviewe

Assessment of the calling detection probability throughout the day of two invasive populations of bullfrog (Lithobates catesbeianus) in Uruguay

Bullfrog invasion is a major conservation concern in South America, so there is an urgent need to detect and monitor its many invasion foci. Amphibian sampling methods commonly use calling display, specifically the nuptial calls of males. With the aim of obtaining the better day period to sample and monitor Lithobates catesbeianus presence, we recorded its calls at three ponds in two invaded localities in Uruguay (Aceguá, Cerro Largo, and San Carlos, Maldonado) during the reproductive season. Then, we studied the records, obtaining a subsample of calling intensity at the first 5 minutes for each hour. We detected that vocalization intensity remained almost constant between 20:00 and 05:00 h. Detection probability remained high and constant during this period, and then decreased. Therefore, bullfrog displays a constant calling activity during the nights of its reproductive period, even longer than native anurans. This long calling period facilitates its detection during nocturnal sampling

Assessment of the calling detection probability throughout the day of two invasive populations of bullfrog (<i>Lithobates catesbeianus</i>) in Uruguay

Bullfrog invasion is a major conservation concern in South America, so there is an urgent need to detect and monitor its many invasion foci. Amphibian sampling methods commonly use calling display, specifically the nuptial calls of males. With the aim of obtaining the better day period to sample and monitor Lithobates catesbeianus presence, we recorded its calls at three ponds in two invaded localities in Uruguay (Aceguá, Cerro Largo, and San Carlos, Maldonado) during the reproductive season. Then, we studied the records, obtaining a subsample of calling intensity at the first 5 minutes for each hour. We detected that vocalization intensity remained almost constant between 20:00 and 05:00 h. Detection probability remained high and constant during this period, and then decreased. Therefore, bullfrog displays a constant calling activity during the nights of its reproductive period, even longer than native anurans. This long calling period facilitates its detection during nocturnal sampling.Asociación Herpetológica Argentina (AHA

Population structure and gene flow of Geoffroy's cat (Leopardus geoffroyi) in the Uruguayan Savanna ecoregion

Felids are among the species most threatened by habitat fragmentation resulting from land-use change. In the Uruguayan Savanna ecoregion, about 30% of natural habitats have been lost, large felids have been eradicated from most of the region, and the impact of anthropogenic threats over the smaller species that remain is unknown. To develop management strategies, it is important to enhance knowledge about species population structure and landscape connectivity, particularly when land-use change will continue and intensify in the next years. In this study, we evaluate the population structure and gene flow of Geoffroy's cat in the Uruguayan Savanna ecoregion. We generated a matrix of 11 microsatellite loci for 70 individuals. Based on Bayesian approaches we found that within the Uruguayan Savanna, Geoffroy's cat shows high levels of genetic variability and no population structure. However, we observed genetic differences between individuals from the Uruguayan Savanna and those from the contiguous ecoregion, the Argentinian Humid Pampa. Four first-generation migrants from Humid Pampa were identified in the Uruguayan Savanna, suggesting a stronger gene flow in the west-east direction. We detected a past bottleneck followed by a subsequent recovery in Geoffroy's cat populations in both ecoregions. These results lay the groundwork to understand the population dynamics and conservation status of Geoffroy's cat in the Uruguayan Savanna ecoregion, and provide baseline data to establish population monitoring.Fil: Bou, Nadia. Ministerio de Educacion y Cultura.; UruguayFil: Soutullo, Álvaro. Universidad de la Republica; UruguayFil: Hernández, Daniel. Laboratorio de Control Ambiental; UruguayFil: Mannise, Natalia. Ministerio de Educacion y Cultura.; UruguayFil: González, Susana. Ministerio de Educacion y Cultura.; UruguayFil: Bartesaghi, Lucía. Ministerio de Educacion y Cultura.; UruguayFil: Pereira, Javier Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Merino, Mariano Lisandro. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Bioinvestigaciones (Sede Junín); ArgentinaFil: Espinosa, Caroline. Universidade Federal do Rio Grande do Sul; BrasilFil: Trigo, Tatiane C.. Museu de Ciencias Naturais; ArgentinaFil: Cosse, Mariana. Ministerio de Educacion y Cultura.; Urugua

Dispersión de la rana toro, Lithobates catesbeianus, y prioridades para su manejo en Aceguá (Cerro Largo)

Presentación de modelos de dispersion de la rana toro, en el marco de un proyecto del Fondo María Viñas.Agencia Nacional de Investigación e Innovació

Dispersal ol Golden Eagles Aquila chrysaetos during their first year of life

Capsule: The area explored increased throughout the year and tended to be much larger for females than males. Aims: To explore how the process of juvenile dispersal unfolds spatially and temporally, and compare the size of the areas explored by the two sexes. Methods: Thirteen chicks were captured between June 2002 and July 2004, tagged with satellite transmitters, and subsequently tracked using the ARGOS system. Results: In both sexes the total area explored increased with time. The average (± sd) size of the area explored in the whole year was 3713 km2 (± 2586) in males and 10 652 km 2 (± 7451) in females. Both the monthly increase in the total area explored (individuals' averages ranging from 22 to 2526 km2) and the overlap between areas used consecutively (about 25%) remained relatively constant throughout the year. Conversely, the size of the area used within a month, and the distance between consecutive areas, increased towards the end of the year; 87.5% of the individuals survived to their first year of life. Conclusions: While females are prominent dispersers and show a more eager exploratory behaviour, males remain within a more restricted area closer to the natal nest, and make more regular use of it. Differences in the total area explored might be linked to differences in food requirements, but other factors are also likely to be involved. © 2006 British Trust for Ornithology.Peer Reviewe

Limited prospecting behaviour of juvenile Eagle Owls Bubo bubo during natal dispersal: implications for conservation

Features of the breeding population and temporary settlement area influence the behaviour of Eagle Owls Bubo bubo prospecting for breeding sites during natal dispersal.Aims To understand how prospecting behaviour during natal dispersal is affected by (i) the main characteristics of the breeding and dispersing portions of the population and (ii) main prey availability.Methods We explored the ten-year dynamics and characteristics of radio-tagged breeders and dispersers of an Eagle Owl population. Results During the first years following natal dispersal there was little prospecting behaviour of nesting sites and birds remained mainly within non-breeding settlement areas, bordering the sector occupied by the breeding population. Settlement areas had an abundant food supply, and low intraspecific competition and mortality. We suggest that these features of the settlement areas may reduce the willingness of individuals to search for breeding sites and may have the potential to impact on the viability of breeding populations.Conclusion From a conservation perspective, the lengthy use of the temporary settlement areas by juvenile Eagle Owls suggests that the sites should be considered as important as the breeding areas when planning conservation strategies. Reducing juvenile mortality in settlement areas may represent an overlooked conservation strategy for long-lived species and may have a crucial effect on the viability some animal populations.Peer Reviewe

The first case of successful breeding of a Golden Eagle Aguila chrysaetos tracked from birth by satellite telemetry

The natal dispersal of a Golden Eagle from its natal eyrie to the site where it reproduced for the first time was monitored. After covering > 16 000 km2 in its three years of juvenile dispersal, and despite flying > 130 km from its natal site, the eagle finally settled in a vacant territory just 26 km away from the place where it had hatched. Almost 95% of the total dispersal area was visited for the first time during the first year of tracking, less than 40% of the dispersal area was used during the remainder of the dispersal period. During dispersal the eagle regularly visited territories occupied by adult Golden Eagles. Previous records of the occupancy of the territory the eagle currently occupies show an alternation between periods when it remained vacant with periods when subadults occupied it. Although the other member of the breeding pair is also a subadult eagle, the birds managed to raise two fledglings.Peer Reviewe