Excess Baggage for Birds: Inappropriate Placement of Tags on Gannets Changes Flight Patterns

• Published in: PloS one Vol. 9; no. 3; p. e92657
• Main Authors: Vandenabeele, Sylvie P., Grundy, Edward, Friswell, Michael I., Grogan, Adam, Votier, Stephen C., Wilson, Rory P.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26.03.2014; Public Library of Science (PLoS)
• Subjects: Acceleration; Accelerometers; Aircraft; Aircraft aerodynamics; Aircraft bird strikes; Animals; Baggage; Biology; Biology and Life Sciences; Biomechanical Phenomena; Birds; Birds - physiology; Ecology; Ecology and Environmental Sciences; Energy expenditure; Energy Metabolism; Feeding Behavior - physiology; Flight; Flight behavior; Flight, Animal - physiology; Geographic Information Systems; Gravity; Laws, regulations and rules; Luggage; Marine ecology; Ornithology; Physical Sciences; Physics; Pitch (inclination); Research and Analysis Methods; Science Policy; Tags; Tails; Transmitters; United Kingdom > UK
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092657

Devices attached to flying birds can hugely enhance our understanding of their behavioural ecology for periods when they cannot be observed directly. For this, scientists routinely attach units to either birds' backs or their tails. However, inappropriate payload distribution is critical in aircraft and, since birds and planes are subject to the same laws of physics during flight, we considered aircraft aerodynamic constraints to explain flight patterns displayed by northern gannets Sula bassana equipped with (small ca. 14 g) tail- and back-mounted accelerometers and (larger ca. 30 g) tail-mounted GPS units. Tail-mounted GPS-fitted birds showed significantly higher cumulative numbers of flap-glide cycles and a higher pitch angle of the tail than accelerometer-equipped birds, indicating problems with balancing inappropriately placed weights with knock-on consequences relating to energy expenditure. These problems can be addressed by carefully choosing where to place tags on birds according to the mass of the tags and the lifestyle of the subject species.