Abstract
Differing environmental conditions can have profound effects on many behaviours in animals, especially where species have large geographic ranges. Seasonal changes or progression through life history stages impose differential constraints, leading to changes in behaviours. Furthermore, species which show flexibility in behaviours, may have a higher capacity to adapt to anthropogenic‐induced changes to their environment. The red‐throated diver (RTD) is an aquatic bird, that is able to forage in both freshwater and marine environments, though little else is known about its behaviours and its capacity to adapt to different environmental conditions. Here, we use time‐depth recorders and saltwater immersion loggers to examine the foraging behaviour of RTDs from three regions across northwest Europe. We found that in the breeding season, birds from two regions (Iceland and Scotland) foraged in the marine environment, while birds from Finland, foraged predominantly in freshwater. Most of the differences in diving characteristics were at least partly explained by differences in foraging habitat. Additionally, while time spent foraging did not change through the breeding season, dives generally became more pelagic and less benthic over the season, suggesting RTDs either switched prey or followed vertical prey movements, rather than increasing foraging effort. There was a preference for foraging in daylight over crepuscular hours, with a stronger effect at two of the three sites. Overall, we provide the first investigation of RTD foraging and diving behaviour from multiple geographic regions and demonstrate variation in foraging strategies in this generalist aquatic predator, most likely due to differences in their local environment.
Highlights
Many species and animal populations are dealing with reduced fecundity and survival from a plethora of anthropogenic pressures, such as marine debris (Horn et al 2020), pollution (Erikstad et al 2013, Amelineau et al 2019) and habitat loss (Harper et al 2008)
Our study provides the first description of foraging behaviour of red-throated diver (RTD) across three geographically distinct regions in northern Europe
We found RTDs predominantly engaged in short, shallow dives of less than 10 m, in foraging bouts ranging from a few minutes to hours
Summary
Many species and animal populations are dealing with reduced fecundity and survival from a plethora of anthropogenic pressures, such as marine debris (Horn et al 2020), pollution (Erikstad et al 2013, Amelineau et al 2019) and habitat loss (Harper et al 2008). These threats can vary widely across geographic landscapes, leading to differential pressures affecting populations (Plumpton and Andersen 1998, Hovick et al 2014). Understanding the fundamental biology of species and changes in their behaviour and ecology over temporal and spatial gradients is key to making informed management decisions to minimise current and future threats (Grémillet and Boulinier 2009)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
