Time, light and sound: nocturnal predators in landscapes of the Anthropocene

Overview

Urbanisation is one of the most pervasive forms of habitat change. More than half of the world’s human population now resides in urban areas, and urban land cover is projected to triple between 2000 and 2030 (1). This poses major threats to single species, biodiversity and ecosystem services (1). Nevertheless, some species may be able to establish in urban areas, where they usually display strong physiological and behavioural changes compared to their counterparts living in natural habitats (2). Ultimately, the future of these urban populations will depend on their ability to adapt to city life (3).
There is increasing recognition that urbanisation can profoundly modify not only the spatial environment, but also the temporal one (4). Particularly critical are artificial light at night and locally elevated sound levels, which can affect the natural rhythmic environment, disrupt organismal clocks, interfere with sensory perception, and ultimately lead to associated changes along the food chain (for example, behaviour of prey) (5). However, such evidence comes mostly from diurnal species, which have been found to expand their activity into the night to extend foraging time and increase mating success, exploiting the presence of light pollution to see and move through the urban night (6, 7). In contrast, there is a surprising lack of data from nocturnal species. Nocturnal species may also be strongly affected by light at night, especially in the case of prey that want to avoid being seen by predators. Moreover, nocturnal predators often hunt using acoustic cues, which makes them susceptible to anthropogenic noise, too (8). On one hand, these acoustic hunters may be forced to forage during quieter periods of the night, for instance by avoiding activity at noisy rush hours. On the other hand, they might switch between sensory cues and rely more on visual hunting in noisy areas, perhaps even exploiting areas polluted by anthropogenic light to find their prey. Distinguishing between these competing, although not fully exclusive hypotheses, will provide novel and exciting insights into how species may adapt to anthropogenic temporal environments.
This project will approach this unique challenge by studying Tawny owls (Strix aluco) (Fig. 1), a nocturnal predator that usually prey by sound. Individual owls will be tracked around-the-clock, using accelerometers to detail behaviour (Fig. 2), GPS to detail space use (Fig. 3), and soundmeters and lightmeters to detail the sensory environments experienced by the birds. Simultaneously, we will quantify the lightscapes and soundscapes in which these raptors move, by around-the-clock, on-animal recordings using dedicated sensors. We will further collect data from nests about provisioning rates, delivered food items, and breeding success. Specifically, this project has three fundamental objectives:
• Objective 1: Timing of activities in city- and forest-dwelling owls: To quantify the plasticity in timing of Tawny owls using accelerometry data.
• Objective 2: Moving through urban lightscapes and soundscapes: To examine how sensory pollutants (light and noise) shape foraging behaviour and foraging efficiency. To this end we will use on-bird measures of light and high-resolution GPS data, and from ground measurements of noise. Using these data, we will build movement models to identify spatio-temporal responses of owls to time-structured, anthropogenic changes to their habitats.
• Objective 3: Links to diet and reproductive success: To identify how the modified use of time and space in urban areas impacts on diet and reproductive success. Decreased parental foraging efficiency, delivery of fewer or lower quality food items, and disrupted rest phases could all impact nestlings’ body condition and fledging success.

Methodology

The study is in collaboration with Dr Patrik Karell from the Novia University of Applied Sciences (also affiliated with Lund University in Sweden) in Finland, who will provide access and support for field work with Tawny owls in Sweden, Prof Barbara Helm from the Swiss Ornithological Institute (expert on circadian rhythms in birds), Dr Petra Sumasgutner at the Konrad Lorenz Research Centre in Austria (expert in urban ecology and raptors) and Dr Dan Chamberlain in Turin (expert in urban ecology). Thus, there will be ample opportunities for the student to expand their research network and thus the project itself (including new ideas and methodologies), and to be exposed to a vibrant research environment.

Field work will be conducted in Scotland (Glasgow and surrounding forest areas) under the supervision of Dr Dominoni and Sweden (Gothenborg and surrounding forest areas) under the supervision of Dr Karell. Tawny owls breed in nestboxes, making an ideal system for studies combining monitoring of reproductive activities with catching and tagging animals for biotelemetry data collection.
This project will use novel biotelemetry technology consisting of tags fitted with GPS, accelerometer and light logger sensors, produced by project partner Technosmart. Field work will involve monitoring of breeding events, catching and ringing adults and chicks, tagging adults, recording of provisioning behaviour and diet via nest-cameras. Pilot data exist (Figs 2-3) for owl movements and activity, and for lightscapes (www.lightpollutionmap.info).
The student will identify an appropriate framework to model both temporal and spatial effects of sensory pollutants on activity levels, home range and characteristics of hunting behaviour (e.g. Generalised Additive Models with auto-regressive terms, or Bayesian state-space models). This shall allow to fully characterise the roles of time, space and explanatory variables, permitting projections and interpolations to non-censused areas. Finally, using GLMMs links will be made between spatio-temporal habitat use of urban and forest owls to changes in diet and reproductive success.

Project Timeline

Year 1

Y1—Months 0-6: Kick-off meeting with supervisory teams, literature review; Months 6-12: pilot field work in Scotland to collect movement and activity data with GPS loggers, attendance of workshops on spatial ecology and advanced statistics.

Year 2

Y2: Months 0-6: Attendance of workshop on analysis of spatio-temporal movement data, pilot analysis; Months 6-12: field work as in year 1, analysis and write up for objective 1, initiate analyses for objective 2.

Year 3

Y3: Months 0-6: Field work in Sweden, further analyses for objective 2 and 3; Months 6-12: attendance of scientific writing course, manuscript preparation, attendance of scientific meeting.

Year 3.5

Y3.5: Months 0-6: Attendance of international scientific meeting, completion of manuscripts and submission of thesis.

Training
& Skills

The training provided by this project will cover a broad suite of important formal quantitative and computational approaches and their application. This, combined with extensive field work with birds, will provide the student with an extremely strong basis for pursuing independent research in their field(s) of interest or for a transition to roles in growth areas such as data science.
The scholar will be based within IBAHCM under the supervision of Dr Davide Dominoni. At IBAHCM the student will be exposed to a vibrant research environment that takes pride in its strong collaborative approach to scientific research. Several special interest groups are present in the institute that will help the student develop theoretical knowledge and practical skills, including the Avian Biology group, the Spatial Ecology group and the Statistical Ecology group.
In year 1, the student will receive training on spatial modelling, GIS, management of large datasets, Bayesian statistics, by following dedicated courses offered within IBAHCM, by attending external specific workshops and courses, and through the support of the supervisors (DD and MB in particular). The student will also receive training on using the University of Glasgow computing cluster to enable rapid data processing. In year 2, the student will develop skills in spatio-temporal modelling of biotelemetry data, integrating different datasets on movement data and environmental variables, with training from MB, external collaborators and specific training courses. The student will also join retreat sessions on scientific writing and will start to lay out the first manuscript. He/she will also spend time with Dr Bogdanova at CEH to discuss analyses of movement data. In year 3, through participation in Institute seminars and national and international conferences, she/he will also develop presentation and communication skills.

References & further reading

1. K. C. Seto, B. Guneralp, L. R. Hutyra, Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools. PNAS. 109, 16083-16088 (2012).
2. M. Alberti et al., Global urban signatures of phenotypic change in animal and plant populations. Proc. Natl. Acad. Sci., 201606034 (2017).
3. M. T. J. Johnson, J. Munshi-South, Evolution of life in urban environments. Science. 358, eaam8327 (2017).
4. B. Helm et al., Two sides of a coin: ecological and chronobiological perspectives of timing in the wild. Philos. Trans. R. Soc. London B.
5. D. Dominoni, J. Borniger, R. Nelson, Light at night, clocks and health: from humans to wild organisms. Biol. Lett. 12, 20160015 (2016).
6. D. M. Dominoni, B. Helm, M. Lehmann, H. B. Dowse, J. Partecke, Clocks for the city: Circadian differences between forest and city songbirds. Proc. R. Soc. B Biol. Sci. 280 (2013), doi:10.1098/rspb.2013.0593.
7. B. Kempenaers, P. Borgström, P. Loës, E. Schlicht, M. Valcu, Artificial night lighting affects dawn song, extra-pair siring success, and lay date in songbirds. Curr. Biol. 20, 1735-1739 (2010).
8. J. T. Mason, C. J. W. McClure, J. R. Barber, Anthropogenic noise impairs owl hunting behavior. Biol. Conserv. 199, 29-32 (2016).

Further Information

Applications: for information on the application process and the IAPETUS2 DTP please see: https://www.iapetus2.ac.uk/how-to-apply/.

This project is in competition with others for funding, and success will depend on the quality of applicants. Funding includes tuition fee waiver for Glasgow University, a competitive stipend, and research support. To express interest please first contact Dr Davide Dominoni (Davide.Dominoni@glasgow.ac.uk) by early January 2022, including a paragraph detailing your reasons for applying and how your experiences fit the project.

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