Flap or soar? Flight strategies of the Manx Shearwater

Rory Gibb (Institute of Zoology, Zoological Society of London, Regent's Park, UK) and colleagues have published in the Journal of the Royal Society Interface on flight patterns in Manx Shearwaters Puffinus puffinus.

The paper’s abstract follows:

“Global wind patterns affect flight strategies in many birds, including pelagic seabirds, many of which use wind-powered soaring to reduce energy costs during at-sea foraging trips and migration. Such long-distance movement patterns are underpinned by local interactions between wind conditions and flight behaviour, but these fine-scale relationships are far less well-understood. Here we show that remotely-sensed ocean wind speed and direction are highly significant predictors of soaring behaviour in a migratory pelagic seabird, the Manx shearwater (Puffinus puffinus). We used high-frequency GPS tracking data (10Hz) and statistical behaviour state classification to identify two energetic modes in at-sea flight, corresponding to flap-like and soar-like flight. We show that soaring is significantly more likely to occur in tailwinds and crosswinds above a wind speed threshold of around 8ms-1, suggesting that these conditions enable birds to reduce metabolic costs by preferentially soaring over flapping. Our results suggest a behavioural mechanism by which wind conditions may shape foraging and migration ecology in pelagic seabirds, and thus indicate that shifts in wind patterns driven by climate change could impact this and other species. They also emphasise the emerging potential of high-frequency GPS biologgers to provide detailed quantitative insights into fine-scale flight behaviour in free-living animals.”

Manx Shearwater, photograph by Nathan Fletcher

See a popular article on the paper here.

Reference:

Gibb, R., Shoji, A., Fayet, A.L., Perrins, C.M., Guilford, T. & Freeman, R. 2017.  Remotely sensed wind speed predicts soaring behaviour in a wide-ranging pelagic seabird.  Journal of the Royal Society Interface DOI: 10.1098/rsif.2017.0262.

John Cooper, ACAP Information Officer, 28 July 2017