Maximizing detection probability for effective large‐scale nocturnal bird monitoring

The importance of population contextual data for large-scale biomonitoring using an apex predator: The Tawny Owl (Strix aluco)

Top predators are often used as sentinel species in contaminant monitoring due to their exposure and vulnerability to persistent, bioaccumulative and, in some cases, biomagnificable contaminants. Some of their ecological traits can vary in space and time, and are known to influence the contamination levels and therefore information on ecological traits should be used as contextual data for correct interpretation of large-scale contaminant spatial patterns. These traits can explain spatiotemporal variation in contaminant exposure (traits such as diet and dispersal distances) or contaminant impacts (traits such as population trend and clutch size). The aim of our research was to review the spatial variation in selected contextual parameters in the Tawny Owl (Strix aluco), a species identified by the COST Action European Raptor Biomonitoring Facility as one of the most suitable candidates for pan-European biomonitoring. A considerable variation in availability of published and unpublished contextual data across Europe was found, with diet being the most extensively studied trait. We demonstrate that the Tawny Owl is a suitable biomonitor at local scale but also that taking spatial variation of other contextual data (e.g. diet) into account is necessary. We found spatial gaps in knowledge about the species ecology and biology in Southern Europe, along with gaps in certain population parameters (e.g. population trends) in several countries. Based on our findings, we proposed a minimal recommended scheme for monitoring of population contextual data as one of the first steps towards a pan-European monitoring scheme using the Tawny Owl.

Bird Communities and the Rehabilitation of Al Karaana Lagoons in Qatar

Qatar, a peninsular country in the Persian Gulf, is significant to avian species due to its location along the African–Eurasian Flyway, a key migratory path. Receiving untreated domestic and industrial liquid waste from Qatar in the past, Al Karaana Lagoons have since been reconstructed as an artificial wetland to address the growing environmental concern posed by contamination build-up. This study documents the changes in biodiversity at Al Karaana Lagoons following their environmental remediation. Data collected (2015 and 2017) by Ashghal (Public Works Authority) prior to project implementation was analyzed alongside data collected independently following project completion (2019–2021). There was a marked increase in bird biodiversity following remediation, including substantial use by migratory species and resident breeders. Further analysis of water quality data of the TSE (treated sewage effluent) ponds shows that they are eutrophic but still support substantial bird life. The project’s success demonstrates how reclaimed lands can provide important habitats to local and migratory birds and encourages similar restoration efforts in the future in both Qatar and elsewhere. We call for the continued monitoring of the site and the implementation of guidelines for the use of the site that balance human activities and habitat quality.

Colonization of Urban Habitats: Tawny Owl Abundance Is Conditioned by Urbanization Structure

Natural habitats are being altered and destroyed worldwide due to urbanization, leading to a decrease in species abundance and richness. Nevertheless, some species, including tawny owls, have successfully colonized this novel habitat. Consequences at the population level have not been described; thus, our main objective was to describe the effects that urban structure have on the tawny owl population at local and landscape levels. Data were obtained from 527 survey points over 7 months in a large-scale owl survey in the Basque Country (northern Spain) in 2018. At the local scale, the interaction between forest and urban cover affected tawny owl abundance, the optimum being in medium forested areas. The interaction between urban cover and clumpiness index (urban patch distribution) showed a generally negative effect. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. In conclusion, at the local scale, when a minimal forest structure is present in urbanized areas, the species can exploit it. At the landscape scale, it prefers smaller urban towns to cities. Thinking ahead, the current tendency toward "green capitals" should benefit tawny owl populations.