Jesús Duarte

We performed a before–after control–impact (BACI) experiment to assess the impact of red-legged partridge releases on mammalian predators, a common game management measure. During three consecutive years (2014–2016), 100 farm-reared red-legged partridges were kept every year for four weeks in an acclimatisation pen on a hunting estate in southern Spain. Before and after releasing the birds, we estimated partridge and predator abundances in a 1000 m buffer around the release point and at a second point where no partridges were released as a control. Results showed that red fox and red-legged partridge abundances increased significantly close to the release points immediately after releasing the birds. Fox abundance was significantly associated with partridge abundance and distance to the pen. Other non-fox predators did not show the same patterns, nor did their abundance increase after the release. The experimental results suggest that the red fox is the main mammalian predator associated with the released birds and that partridge releases may produce an attraction effect on this predator species. The release of partridges can adversely affect the image of the fox as a predatory species that may take advantage of a newly abundant resource, creating a conservation problem that encourages conflict between predators, without distinguishing species, and hunters.

The presence of wild species in urban areas is becoming increasingly common. In southern Spain, species such as wild boar cause significant damage and problems in human-dominated environments, such as peri-urban areas, sports facilities, and urban parks. Here, we used camera trapping to monitor the entry rates of ungulates (wild boar and red deer) into three golf courses located in urban areas in southern Spain. The courses are surrounded by hunting estates and other non-urban areas where species are controlled through lethal methods. Wild boars are controlled year-round, and red deer are controlled during specific hunting periods. We tested for differences during periods of normal human activity and periods of the COVID lockdown using generalised linear mixed models. We controlled ungulate raids for 2639 trapping nights, obtaining 1093 wild boar and 225 red deer independent events. During the COVID lockdown, wild boar raids on golf courses decreased significantly. Meanwhile, equivalent deer raids increased significantly during the hunting period. The results indicate that certain urban areas where control by firearms is not permitted—such as golf courses—can function as safe zones for wild species. This reserve effect is related to the structure of the urban habitat and the resources it offers in terms of security and food.

La crisis energética mundial desencadenada por la invasión de Rusia en Ucrania provocó un aumento sin precedentes en el uso de energías renovables. Según la Agencia Internacional de la Energía, para 2027 la energía solar fotovoltaica (FV) será la fuente de energía con mayor capacidad eléctrica instalada en el mundo. Sin embargo, el desconocimiento de su impacto en la fauna silvestre a medio y largo plazo es preocupante. En este estudio se monitoreó la ocurrencia de aves rapaces en una planta solar FV, ubicada en Andalucía, España, durante los dos primeros años y medio de funcionamiento. Se registraron seis especies dentro de la instalación solar FV. Las más frecuentes fueron Buteo buteo y Falco tinnunculus, observadas en el 88,9% de los muestreos, seguidas de Milvus migrans con un 83,3% y Milvus milvus con un 55,6%. Las menos frecuentes fueron Hieraaetus pennatus y Athene noctua, observadas en el 16,7% y 5,6% de los muestreos, respectivamente. Los comportamientos observados con mayor frecuencia dentro de la instalación solar FV fueron: posado (38,1%) y vuelos direccionales (37,7%), seguidos de caza (14,8%), volteretas (9,1%) y vuelos territoriales y de cortejo (0,3%). Los resultados son notables debido al uso que hacen las rapaces, el cual, al menos en el presente estudio, muestran la compatibilidad entre este tipo de infraestructuras de producción de energía y la ocurrencia de estas aves. No obstante, la ausencia de datos sobre las condiciones preexistentes antes de la instalación de la planta solar FV dificulta la capacidad para determinar con precisión el verdadero impacto de estas infraestructuras sobre las rapaces. [Traducción de los autores editada]

As human activities such as urbanization encroach on natural areas, some wildlife species adapt to these changes and learn ways to utilize newly available resources. We monitored the use patterns of the Eurasian otter in three urban ponds in southern Spain (Málaga province). We compared weekly otter visits and relative spraint abundance between the urban ponds and two control ponds located in natural areas, testing for differences in use patterns between them using Generalized Linear Mixed Models and the Wald–Wolfowitz run test. We also estimated prey survival rates through Kaplan–Meier estimator curves. We also assessed problems of coexistence with human interests. Relative spraint abundance was not affected by pond type (urban or natural). However, the number of otter visits was lower for urban ponds, and the pattern was not random but concentrated over a short time until prey depletion, suggesting consistent use of the urban feeding patches. Available food resources in urban settings can become a viable option for otters, which appear to explore urban habitats when it suits them. However, in the monitored urban ponds, otters competed with human interests and generated a conservation problem that almost led to lethal measures.

Between 2019 and 2022 we carried out a survey to update the distribution data of the red squirrel in the province of Málaga. Fifteen years after the last elaboration of the distribution atlas, it was likely that this forest species had expanded in step with the increase in forest mass in the province. The results show that the species has expanded in the province, increasing its distribution range between 24.8% and 27.7% and almost tripling the number of UTM grid squares. The species has colonised the region of Antequera, the mountains of the Arco Calizo Central and the banks of the Genil River in the north of the province. To the south it has expanded towards the urban environments of the city of Málaga and has begun its expansion towards the west. In the extreme northeast, the species has made less progress, colonising some new areas just beyond the limits of the Sierra Tejada, Almijara and Alhama Natural Park. Most of the new populations are geographically closer to the population at Montes de Málaga, which seems to have served as the main source population. In the eastern area, subtropical crops seem to function as a barrier limiting further expansion. We propose and discuss a series of hypotheses regarding the origin of the population and the need to undertake future studies of historical, genetic, and epidemiological distribution models.

In this study, we evaluated predation of the ocellated lizard on red-legged partridge nests in an olive grove in southern Spain over three consecutive years. The microhabitat characteristics of prey nests are analysed through comparison with successful nests. We found only 13 nests predated by lizards during the study period. This number was three times lower than that of nests that failed due to causes related to agricultural practices or human activity in the same period and study area. A few of the nests were predated by mammals more than they were preyed upon by lizards. The nests preyed on by lizards were associated with proximity to their refuge areas (e.g. stone piles, old buildings with holes, or rabbit burrows). The characteristics of the olive grove (e.g. drip irrigation and absence of vegetation under the olive trees) may favour the ocellated lizards' search-and-hunt strategy, which allows a lizard to readily find a nest if it is inside the lizard's territory and close to its refuge. We propose management strategies for reducing lizard-related nest losses. However, we argue that olive grove intensification is a major cause of partridge nest failure rather than predation by lizards and other predators.

Today, governments and administrations strive to minimise issues associated with Feral Pigeon (Columba livia var. domestica) colonies in urban areas. Scientific evidence has demonstrated that control measures are ineffective in the long term, and colonies recover rapidly. Most scientific research has occurred under high-density circumstances, primarily in large city centres. Moreover, very few studies have been conducted in residential zones or suburban areas where colony densities are lower, but where Feral Pigeons generate the same issues. In this study, we analysed the recovery time of Feral Pigeon colonies in 11 buildings in low-density urban areas where control campaigns were previously conducted to reduce their abundance. Recovery times were highly variable among the buildings (50–3072 days). Distance to the nearest uncontrolled colony of Feral Pigeons, i.e., a source area, was the primary factor that contributed to recovery time, which significantly increased with increasing distance to source colonies. Thus, buildings closest to the Pigeons’ source areas (500 m away from source areas. Our findings highlight the relevance of identifying an effective management unit for the implementation of control programmes to reduce immigration rates and increase long-term effects.

We monitored the incidence of predation behavior in Eurasian otters (Lutra lutra) from urban ponds in southern Spain, following reports of the mustelids’ presence in various urban locations. In one of the case studies, 30 small common carp and 35 Koi fish were released in May 2017 and April 2018, respectively, into two different ponds. Otters extensively predated on these fish over a period of 75–80 days. Only two small carp (6.6%) survived in one of the ponds and 10 Koi fish (28.5%) in the other. The surviving Koi were relocated. We determined that fish survival functions and mortality rates between these two years were not significantly different. At the second urban location, otters extensively predated on Iberian frogs over a period of 5–6 days in May 2018, left the area, and repeated this pattern in May 2019. Finally, at the third urban location, otters consumed 20 goldfish in 16 days in August 2018. Our results indicate that available food resources in urban settings can become a viable option for certain bold individuals of wildlife species and that otters appear to explore urban habitats when it suits them. Appropriate management and damage control strategies are therefore needed to ensure the survival of this protected species in case food resources in the wild become limited and urban raids become habitual.

Linear infrastructure intrusions into natural ecosystems, such as motorways and high-speed railways, causes direct loss of habitat but also impacts fauna through collisions. Wildlife road mortality is well documented and extensive conservation legislation exists in many countries to minimise the negative impact of these infrastructures. However, although these measures are implemented because of legislation, these structures are often not adequately maintained. Here we present data on the functionality of perimeter fences along two motorways in Malaga province (southern Spain) erected to prevent collisions with the common chameleon (Chamaeleo chamaeleon). We sampled the fences along the 14 km of the two motorways included in the 17 1 × 1 km squares of the study area. Our results show that the reptile fence is permeable throughout at those points where the metal sheeting was absent and where the vegetation had overgrown around the fence, hence allowing chameleons to cross. Given our results, we conclude that this situation is likely to be similar in other regions of Spain and in other countries. This is because construction/concessionary companies do not consider the environmental impact of construction projects in the medium and long term, and environmental authorities do not ensure that companies comply with the legislation.