Aim Abundance of small passerines may be distributed over large wintering areas according to geographical patterns that are difficult to detect. This may prevent the identification and conservation of the most suitable sectors, or the detection of local and regional features affecting the species during winter. In this paper, we explore the usefulness of ring recoveries to predict bird distribution in wintering grounds by using Maxent, one of the presence-only techniques available for modelling species distributions. We test whether suitability indices obtained in 2.5 · 2.5 km UTM squares from ring recoveries were positively correlated with the actual abundance of robins (Erithacus rubecula) and blackcaps (Sylvia atricapilla) inside the squares.Location Spain.Methods We used 686 and 1139 localities across the country in which blackcap and robin ring recoveries were recorded by the Spanish Office of Migratory Species to generate the suitability maps. In addition, we sampled bird abundance inside 70 control squares independent of ring recovery localities along a belt crossing mountains, highlands and lowlands of the Iberian Peninsula during January from 2006 to 2011.Results Suitability indices predicted by Maxent were positively correlated with robin (r = 0.42, n = 70, P < 0.001) and blackcap (r = 0.52, n = 70, P < 0.001) abundances in the 70 control squares along the belt crossing the Iberian Peninsula.Main conclusions These results suggest that the use of distribution models with ring recoveries may be used to describe the habitat suitability of the winter ranges of small, common passerines. This also means that the huge number of ring recoveries stored in national and transnational data banks could be used to explore the factors shaping bird ranges and to forecast the geographical distribution of suitable wintering areas of migratory birds in large, poorly known regions. This may be useful in biogeography and conservation.

In Europe, wild ungulates have undergone major expansion and population growth during recent decades. In certain cases, the high density achieved by these populations has led to excessive pressure on the environment, which eventually becomes a limiting factor for the population itself. One of these reintroductions was performed with the Iberian ibex (Capra pyrenaica Schinz, 1838) in the Sierra de Guadarrama National Park (Spain). This reintroduced population was monitored during six field seasons (2000, 2003, 2005, 2007, 2010, and 2014) by direct observation of the animals along transects using the distance sampling method to determine the degree of expansion over the years and the use of different habitats according to different seasons. The abundances obtained for each field season showed a significant increase from 4.16 to 8.65 individuals/km, showing a linear relationship between abundance and extent of the area occupied by the species. We observed that differences between habitat availability and use were significant for all seasons. Our data can be used as an example of the colonization process of a population of wild ungulates and their impact on vegetation to better manage future reintroductions.

Abstract:One reintroduced population of Iberian ibex was monitored between 2000 and 2007 in the Sierra de Guadarrama National Park (Central Spain) using the distance sampling method. The densities obtained from three samplings show a significant increase between 2000 (6.57 ind./km 2 ) and 2007 (33.16 ind./km 2 ) despite a range extension. After an initial period of balance, the sex ratio became unbalanced over time in favor of females. The age pyramid also changed after a dramatic population increase. The birth rate oscillated at relatively high values for the species (0.69-0.99 kids/female). The group size reduced significantly over time. Females with kids dispersed from the release area significantly less than males and mixed groups.

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ResumenLa presencia de la cabra montés (Capra pyrenaica) en el Parque Nacional de la Sierra de Guadarrama (Madrid) se remonta a las reintroducciones realizadas a principios de la década de 1990. Desde entonces, la población ha experimentado un incremento exponencial que ha provocado una elevada presión sobre el medio, especialmente sobre la vegetación. Desde el año 2000 se vienen realizando censos periódicos que han permitido conocer la evolución de la población y su ubicación dentro del Parque. Con este trabajo se pretende elaborar "mapas de presencia" teniendo en cuenta no sólo la situación actual sino también la presencia histórica y la continuidad de la especie dentro del parque. A partir de los censos realizados y considerando 5 variables diferentes (número de individuos presentes, estacionalidad, número de años con presencia, incremento poblacional y presencia estos últimos años) se han determinado cuáles han sido las zonas que han tenido una presencia mayor y más continuada de la especie desde su reintroducción. Se han establecido 5 zonas dentro del Parque Nacional, siendo las zonas de La Najarra y Cuerda Larga las que muestran una mayor presencia y continuidad, las zonas aledañas de Pedriza Anterior y Posterior muestran una presencia relativamente alta, la cuerda de Montes Carpetanos tiene una presencia más reciente y es nula en zonas periféricas del Parque (Siete Picos y cuerda de Navarredonda). AbstractThe presence of the Iberian Ibex (Capra pyrenaica) in the Parque Nacional Sierra de Guadarrama (Madrid) dates back to the reintroductions made in the early 1990s. Since then, the population has experienced an exponential increase causing high pressure on the environment, especially on the vegetation. Periodic censuses have been carried out from 2000 which have allowed us to track the evolution of the population and its location within the Park. The aim of this work is to draw up 'presence maps' taking into account not only the current situation but also the historical presence and the continuity of the species within the National Park. Based on censuses carried out since 2000 and considering 5 different variables -number of individuals present, seasonality, number of years with presence, population increase and presence in last years-, the areas that have had the greatest and most continuous presence of the species has been determined since its reintroduction. There have been established five zones within the National Park, showing the area of La Najarra and Cuerda Larga a greater presence and continuity, the surrounding areas of Pedriza Anterior and Pedriza Posterior a moderate presence, the Montes Carpetanos rope shows a lower presence and is null in peripheral areas of the Park (Seven Picos and Navarredonda rope).