Bruno Herlander Martins

Aquila verreauxii es considerada un depredador altamente especializado que se alimenta principalmente de damanes y ocupa hábitats montañosos escarpados a lo largo de su distribución en África y la Península Arábiga. A pesar de su gran tamaño y de sus similitudes morfológicas con rapaces carroñeras, el consumo de carroña ha sido raramente documentado y no se había registrado previamente en la Península Arábiga. En este estudio reportamos el primer caso confirmado de uso sostenido de carroña por Aquila verreauxii en Arabia Saudita, documentado mediante cámaras activadas por movimiento en una estación de cebo en la Reserva de la Biosfera Harrat Uwayrid, en la región de AlUla, al noroeste de Arabia Saudita. Dos individuos de Aquila verreauxii visitaron un cadáver de cabra en la estación de cebo durante cuatro días consecutivos en diciembre de 2024, con una presencia combinada que superó las 11 horas. Las águilas mostraron alimentación repetida y prolongada, sin aparente reticencia en la explotación de la carroña ni competencia interespecífica. No se registraron buitres ni otras grandes rapaces en el sitio durante el período de cuatro días. Nuestras observaciones sugieren que la carroña puede representar una oportunidad de alimentación de bajo costo para Aquila verreauxii en este entorno árido, donde las presas tradicionales pueden ser menos abundantes. Nuestras observaciones también aportan evidencia adicional de flexibilidad conductual en una rapaz típicamente considerada un depredador obligado. Este estudio resalta el valor del seguimiento sistemático para detectar comportamientos poco frecuentes y mejorar el conocimiento de la ecología trófica de las rapaces en regiones poco estudiadas. [Traducción de Bruno Herlander Martins]

Worldwide, humans have altered ecosystems not only by reducing and changing the distribution of resources but also by providing new foraging opportunities to wildlife. However, little is known about the early-life development and maintenance of new foraging behaviours, which are crucial for species to adapt to human-induced environmental changes. Using a longitudinal global positioning system (GPS)-tracking dataset from 71 adult and 147 juvenile white storks (Ciconia ciconia) tracked for up to 6 years, this study investigates shifts in the exploitation of landfill resources during ontogeny and explores whether selective survival, within-individual improvements or both shape the emergence of this behaviour. Landfill use was found to increase with age. From their second year of life onwards, white storks visit landfills more often than in their first year, forage more in areas with abundant organic waste and reduce their foraging energy expenditure. Overall, this study reveals that the age-related increase in the use of anthropogenic food sources is driven primarily by within-individual improvements operating most strongly in early life, rather than by selective survival of individuals that most frequently and proficiently use landfill sites. As more species rely on anthropogenic food subsidies, this work highlights how opportunistic species cope with and adapt to human-driven environmental change, influencing individual lifetime decisions and potentially impacting population dynamics.

The development and miniaturization of GPS tracking devices has enabled a better understanding of migration phenology, but it can be challenging to identify where and when migration starts and ends, and researchers rely on multiple methods to infer it. Here, we use GPS tracks of 18 trans‐Saharan migrant White Storks Ciconia ciconia to determine how the choice of method influences the estimation of migratory timing and discuss its implications. We evaluate and provide R code for the implementation of five alternative methods: spatial threshold, absolute displacement, spatio‐temporal displacement, net squared displacement and change point analysis. Spatial threshold, absolute displacement and spatio‐temporal displacement methods produce, in most cases, significantly different estimates of migration timing and duration as compared with net squared displacement and change point analysis.

Agama agama is a successful invader that was recently introduced to Santo Antão Island of the Cape Verde archipelago. The species was then noted to be present also in São Vicente and Santiago Islands but the geographic origin of the introductions remains undetermined. Given its wide range and taxonomic identification problems, we compared new 16S RNA sequences with available Agama agama sequences in order to determine if some geographical structure was present that allowed identification of the country of provenance and number of introduction events on the Cape Verde Islands. Some geographical structure of genetic diversity and reasonably large within-group average divergence were revealed, especially in the countries around the Gulf of Guinea. Results support a single origin for this introduction, as a single 16S haplotype is found among the three Cape Verde Islands, and suggest Liberia as the country with the smallest genetic distance to the individuals found in the Cape Verde archipelago. We suggest that local authorities take action against this exotic species as it is spreading and reproducing and predation on endemic species of reptile has been confirmed.

Despite the increasing worldwide use of global positioning system (GPS) telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects. We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra). The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55). GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%). Our results suggest that GPS telemetry is reliably applicable to riparian and even diving freshwater animals. They also highlight the need, in GPS wildlife studies, for performing site-specific pilot studies on GPS functioning as well as for taking into account eventual spatial and temporal correlation of location estimates. The limited price, small dimensions, and high performance of the device presented here make it a useful and cost-effective tool for studies on otters and other aquatic or terrestrial medium-to-large-sized animals.