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Clues used by migrant birds to select sites for stopover are much less known than their reasons for leaving. Habitat characteristics and geographical location may affect the decision to use an island as a stopover site in different ways for different species. Thus, abundance and composition of migrants may be expected to differ between islands. Using standardized ringing from 9 western Mediterranean islands we evaluate drivers of abundance of trans-Saharan migrant passerines, specifically the role of species continental abundance, island characteristics and geographical location. Although continental abundance is a main driver of migrant composition on all islands migrant composition differs between them. Redundancy analysis and species response models revealed that the main drivers were distance to the nearest land toward the south, which has a positive effect on the number of migrants of most species, and island area, which appears as an important cue used for selecting a stopover island. Species whose abundance is positively related to island area have more pointed wings while species affected by distance to land toward the south have relatively more rounded wings. This suggests a hypothesis on the mechanism that may generate differences in passerine migrant composition between islands based on better efficiency of more pointed wings for long-distance flight.

Spatial population synchrony is a key aspect in ecology. Normally, three mechanisms have been identified to explain similar temporal variations in abundance between spatially separated populations: Moran effect, trophic interactions and dispersal. We analysed the spatial synchrony of the abundance of five diving waterfowl species (White-Headed Duck, Black-Necked Grebe, Red-Crested Pochard, Common Pochard and Common Coot) by conducting a monthly census from October 2013 to September 2019 in 34 lakes located in Central Spain. Twenty-eight independent variables related to the hydroperiod, anthropogenic impacts, landscape and structural variables were tested in relation to temporal patterns. Synchronised lakes groups were identified for all species, with differential associations with variables. The variables associated with spatial synchrony were: Distance between lakes (White-Headed Duck and Common Pochard); Natural vegetation area in lakes (Red-Crested Pochard) and Accumulated precipitation until the breeding season (Common Pochard and Common Coot). For Black-Necked Grebe, no variable was associated with the observed temporal patterns. These results provide the first evidence for the mechanisms behind the spatio-temporal synchronisation of diving waterbirds populations in the central Iberian region.

[EN] Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as the leukocyte profiles, in the threatened Dupont’s Lark (Chersophilus duponti), using samples from Spain and Morocco. Furthermore, we tested whether variation in H/L ratio was associated with variables such as population density, presence of blood parasites and individual body condition. We found that H/L ratio did not vary between countries, but individuals captured during the breeding season showed higher values of H/L compared to non-breeding ones. Neither male density, nor date within the breeding season had an effect on the H/L ratio. In Spain, individuals with higher body condition showed lower H/L ratio regardless of whether they were malaria-infected. In Morocco, malaria-infected individuals showed higher values of H/L ratio than the non-infected birds. Moreover, we found that our average values of H/L ratio in Morocco were within the ranges of other passerines, but not in Spain. Individuals with higher H/L ratios may be more stressed or present higher capability to face stressful situations. Although H/L ratio is a useful and relatively easy way to obtain measure of stress, the impact that the environment might have on stress and the way it is explained by H/L ratio must be addressed carefully. This study provides new insight for this species’ biology and provides useful reference information to test the status and survival of other populations., [DE] Stress bei Vögeln ist durch die Messung des Verhältnisses von Heterophilen zu T-Lymphozyten (H/L-Verhältnis) umfassend untersucht worden. In dieser Studie wollten wir zum ersten Mal die potentiellen Veränderungen des Stresses in Verbindung mit der Geografie (Unterschiede zwischen einzelnen Ländern) und der Saisonalität (zwischen den Jahreszeiten und innerhalb der Brutsaison), gemessen als H/L-Verhältnis, sowie die Leukozytenprofile bei der bedrohten Dupontlerche (Chersophilus duponti) anhand von Proben aus Spanien und Marokko bewerten. Darüber hinaus haben wir untersucht, ob das H/L-Verhältnis mit Variablen wie der Populationsdichte, dem Vorhandensein von Blutparasiten und der individuellen physischen Verfassung zusammenhängt. Wir stellten fest, dass das H/L-Verhältnis zwischen den einzelnen Ländern nicht variierte, aber die während der Brutzeit gefangenen Tiere höhere H/L-Werte aufwiesen als nicht brütende Tiere. Weder die Dichte an Männchen, noch der Zeitpunkt innerhalb der Brutsaison hatten einen Einfluss auf das H/L-Verhältnis. In Spanien wiesen Tiere mit einer besseren physischen Verfassung ein niedrigeres H/L-Verhältnis auf, unabhängig davon, ob sie mit Malaria infiziert waren. In Marokko zeigten malariainfizierte Vögel höhere Werte des H/L-Verhältnisses als nicht infizierte. Außerdem stellten wir fest, dass unsere Durchschnittswerte für das H/L-Verhältnis in Marokko innerhalb der Werte für andere Sperlingsvögel lagen, nicht aber in Spanien. Tiere mit einem höheren H/L-Verhältnis sind möglicherweise gestresster oder besser in der Lage, mit Stresssituationen umzugehen. Obwohl das H/L-Verhältnis ein nützliches und relativ einfach zu beschaffendes Maß für Stress ist, muss der eventuelle Einfluss der Umwelt auf Stress und die Möglichkeiten, diesen durch das H/L-Verhältnis zu erklären, sorgfältig untersucht werden. Diese Untersuchung bietet neue Einblicke in die Biologie dieser Art und liefert nützliche Referenzinformationen für die Bestimmung des aktuellen St

Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as the leukocyte profiles, in the threatened Dupont’s Lark (Chersophilus duponti), using samples from Spain and Morocco. Furthermore, we tested whether variation in H/L ratio was associated with variables such as population density, presence of blood parasites and individual body condition. We found that H/L ratio did not vary between countries, but individuals captured during the breeding season showed higher values of H/L compared to non-breeding ones. Neither male density, nor date within the breeding season had an effect on the H/L ratio. In Spain, individuals with higher body condition showed lower H/L ratio regardless of whether they were malaria-infected. In Morocco, malaria-infected individuals showed higher values of H/L ratio than the non-infected birds. Moreover, we found that our average values of H/L ratio in Morocco were within the ranges of other passerines, but not in Spain. Individuals with higher H/L ratios may be more stressed or present higher capability to face stressful situations. Although H/L ratio is a useful and relatively easy way to obtain measure of stress, the impact that the environment might have on stress and the way it is explained by H/L ratio must be addressed carefully. This study provides new insight for this species’ biology and provides useful reference information to test the status and survival of other populations.

Urbanisation processes are increasing worldwide at surprising rates affecting wildlife in many ways: changing habitat structure, reducing resources, and modifying the distribution, composition and abundance of local biota. In different countries, urban waste collection techniques are evolving and surface rubbish containers (neighbourhood receptacles for temporarily storing anthropogenic household waste located above-ground on the streets) are being replaced with underground ones (metal boxes with steel chutes that fed into large underground containers) to improve sanitation measures, to avoid bad smells and waste scattering by animals. We aimed to detect if House Sparrows were more abundant close to surface rubbish containers than close to the underground ones. We recorded an abundance index of House Sparrows during two visits in winter 2018–2019 to point counts located in groups of both container types (80 and 85 groups of underground and surface containers, respectively) in eight towns of Eastern Spain. We modelled the abundance index according to rubbish container type, and 14 other environmental variables at four scales: container, nearest buildings, near urban features, and general locality features using GLMMs. House Sparrows were more abundant close to surface than to underground rubbish containers, which may be linked with higher food debris availability. The presence of other urban features (bar terraces, private gardens, mature trees) interacting with the rubbish containers also influenced the abundance of House Sparrows. The replacement of above-ground rubbish containers with underground ones may deprive House Sparrows resources, which could lead to the decline of this species, especially in urban areas with little green cover.

The seasonal survival pattern of a garden dormouse Eliomys quercinus population was studied in a Mediterranean agricultural field area from East Spain, a geographical location in which this species does exhibit no hibernation. Individuals were captured from nest—boxes checked monthly during a 4-year period. Data were analysed using an open population Cormack–Jolly–Seber model including sex, age class and season as factors. Best models included the effect of age and differences in survival between adult males and females. Survival rate was more variable between seasons in males than in females or juveniles. Maximum adult male survival was reached in autumn, decreased in winter and dropped to very low values in spring and summer. Survival of adult females was higher and presented a less marked seasonal pattern. Seasonal survival of juveniles was fairly constant along the year. Recapture probability also varied seasonally and was twice in winter than in the rest of the year. The local annual survival rate obtained in adult females exceeded the survival rate observed in some garden dormouse populations from Italy, but it was considerably lower in comparison to the values obtained in South Spain and France. The possible energetic consequences of the constant sexual activity exhibited by this garden dormouse population and the effect of other factors, such as the availability of food and social interactions between individuals, seem to influence in the seasonal variations in survival rate for this rodent species in this agricultural habitat.

Moon phase affects the ecology and behaviour of animals and may thus affect both circadian and circannual rhythms. Its influence on nocturnal and dawn bird behaviour is known, but fewer studies have examined its effect on passerines’ singing activity, some of which have yielded contradictory findings. With the aim of elucidating whether moon phase affects dawn singing in passerines, we recorded dawn singing activity of the Dupont’s Lark Chersophilus duponti in three mediterranean shrub-steppes, through repeated sampling over three lunar cycles per breeding season in 2 years. Our results corroborate the idea that moon phase affects signalling behaviour of passerines. We found that, on average, dawn singing started 15 min earlier when the moon was full, due to variations in the light intensity, which seems to act as a trigger for singing activity in the Dupont’s Lark. Nonetheless, the dawn chorus finished at the same time regardless of moon phase, maybe due to a low contribution of moonlight as sunrise approaches. As a consequence, performance time increased during full moon nights. However, the total production of songs did not differ between moon phases, and therefore, song rate was lower during full moons. Reduced song rate on full moon nights could be a response of singing males to reduce their predation risk, since singing on bright nights can increase the ability of predators to locate them, but it could be also related to the energetic cost of longer choruses. The consequences of moon phase for mate attraction, reproductive success and behaviour in this and other bird species remain unknown, and thus our research can serve as a starting point from which to develop new studies.

Many European towns and cities have undergone reurbanisation processes in recent decades. However, their effects on urban biodiversity have been poorly studied. Currently urbanisation processes include park remodelling, which involves the replacement of semi-natural substrates (natural grass, bare soil) with artificial ones (pavement, concrete, areas for dogs, artificial grass). Our aim was to explore, for the first time, the effects of park remodelling on the trends and abundance of a declining urban exploiter, the House Sparrow. An abundance index of House Sparrows was obtained in 32 urban parks of four towns in the Valencian Community (Spain) in four summers (2015–2018). Of the studied parks, 10 were remodelled during the study period. Before remodelling, the trends and abundance of House Sparrows in both groups of parks were similar and stable on average, which suggest no bias between both park groups. However, House Sparrow abundance was significantly reduced in parks affected by remodelling works while in those non-remodelled it remained stable. Park remodelling might be linked to a reduction in both habitat suitability and availability of trophic resources, which could harm urban House Sparrows populations and possibly other species as well. Therefore, new park policies and urban planning measures are urgently needed to preserve urban House Sparrows.