Actogram analysis of free-flying migratory birds: new perspectives based on acceleration logging.
The use of accelerometers has become an important part of biologging techniques for large-sized birds with accelerometer data providing information about flight mode, wing-beat pattern, behaviour and energy expenditure. Such data show that birds using much energy-saving soaring/gliding flight like frigatebirds and swifts can stay airborne without landing for several months. Successful accelerometer studies have recently been conducted also for free-flying small songbirds during their entire annual cycle. Here we review the principles and possibilities for accelerometer studies in bird migration. We use the first annual actograms (for red-backed shrike Lanius collurio) to explore new analyses and insights that become possible with accelerometer data. Actogram data allow precise estimates of numbers of flights, flight durations as well as departure/landing times during the annual cycle. Annual and diurnal rhythms of migratory flights, as well as prolonged nocturnal flights across desert barriers are illustrated. The shifting balance between flight, rest and different intensities of activity throughout the year as revealed by actogram data can be used to analyse exertion levels during different phases of the life cycle. Accelerometer recording of the annual activity patterns of individual birds will open up a new dimension in bird migration research.
Department of Biology, Lund University, Ecology Building, 22362, Lund, Sweden. Johan.Backman@biol.lu.se.
Johan
http://orcid.org/0000-0002-4203-9793
J
Bäckman
Department of Biology, Lund University, Ecology Building, 22362, Lund, Sweden.
Arne
A
Andersson
Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
Lykke
L
Pedersen
Department of Biology, Lund University, Ecology Building, 22362, Lund, Sweden.
Sissel
S
Sjöberg
Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
Anders P
AP
Tøttrup
Department of Biology, Lund University, Ecology Building, 22362, Lund, Sweden.
Thomas
T
Alerstam
D061725:Accelerometry; D025041:Animal Migration / Q000502:physiology; D000818:Animals; D004463:Ecology / Q000295:instrumentation / Q000379:methods*; D005426:Flight, Animal / Q000502:physiology*; D020308:Songbirds / Q000502:physiology*
Accelerometer; Activity; Annual cycle; Bird migration; Flight pattern