title: Excess baggage for birds: inappropriate placement of tags on gannets changes flight patterns.
abstract: 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.
authors.affiliation: Biosciences department, College of Science, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Sylvie P
authors.initials: SP
authors.lastname: Vandenabeele
authors.affiliation: Biosciences department, College of Science, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Edward
authors.initials: E
authors.lastname: Grundy
authors.affiliation: College of Engineering, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Friswell
authors.affiliation: RSPCA Wildlife department, Wilberforce Way, Southwater, West Sussex, United Kingdom.
authors.forename: Adam
authors.initials: A
authors.lastname: Grogan
authors.affiliation: Environment & Sustainability Institute, University of Exeter, Cornwall Campus, Penryn, Cornwall, United Kingdom.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Votier
authors.affiliation: Biosciences department, College of Science, Swansea University, Singleton Park, Swansea, United Kingdom.
authors.forename: Rory P
authors.initials: RP
authors.lastname: Wilson
mesh_terms: D000054:Acceleration; D000818:Animals; D001696:Biomechanical Phenomena; D001717:Birds / Q000502:physiology*; D004734:Energy Metabolism; D005247:Feeding Behavior / Q000502:physiology; D005426:Flight, Animal / Q000502:physiology*; D040362:Geographic Information Systems