A flexible GPS tracking system for studying bird behaviour at multiple scales

Abstract

Tracking devices and bio-loggers provide crucial information on the ecology and behaviour of birds in their natural environment. An optimal tracking system should be lightweight, measure three-dimensional locations, enable flexible measurement schemes, transmit data remotely and measure environmental variables and biological parameters of the individual. Giving full consideration to the traits of birds and the constraints of technology, we have developed a GPS tracking system that attempts to achieve most of the aspirations of an optimal tracking system for free ranging birds without the need to recapture them. Here, we describe the design, performance and limitations of the system. We also present measurements on the tracked Lesser Black-backed Gull Larus fuscus to show how such a system can generate new opportunities for research at multiple scales. The GPS tracker weighs 12 g and includes a GPS receiver, micro-processor, 4 MB of memory for data storage, solar panel and battery. It has a tri-axial accelerometer to monitor behaviour. To maximize flexibility, it is equipped with a radio transceiver for bidirectional communication with a ground-based antenna network, which enables data to be downloaded and new measurement schemes to be uploaded remotely. The system facilitates a multi-scale approach to studying bird movement, from fine-scale movements (3-s measurement intervals) to long-distance migratory movements (intervals of 20-30 min) of the same individual. We anticipate that flexible tracking systems that enable researchers to optimize their measurement protocols will contribute to revolutionizing research on animal behaviour and ecology in the next decade.

Social foraging and individual consistency in following behaviour: testing the information centre hypothesis in free-ranging vultures

“…Vultures in France were tracked using GPS transmitters (UvA-BiTS, Amsterdam, The Netherlands) [40] deployed with a leg-loop harness [41,42]. No adverse effects on behaviour (either breeding or survival rate), were observed during the study.…”

Unexpected diversity in socially synchronized rhythms of shorebirds

“…2). (3) For nine nests a GPS tag, mounted on the back of the bird, recorded the position of the bird 36 . The precision of the position depends on cloud cover and sampling interval 36 .…”

“…(3) For nine nests a GPS tag, mounted on the back of the bird, recorded the position of the bird 36 . The precision of the position depends on cloud cover and sampling interval 36 . Hence, to account for the imprecision in GPS positions, we assumed incubation whenever the bird was within 25 m of the nest (Extended Data Fig.…”

Stacked space-time densities: a geovisualisation approach to explore dynamics of space use over time

“…6). Data were collected using the UvA Bird Tracking System (http://www.uva-bits.nl/, [6]). Nest-locations for each of the individuals are also known.…”