The puffin has adopted a clever hunting strategy
THE Atlantic Puffin with its huge, colourful, parrot-like bill, its very large, pale, summer cheek patches and what often appears to be a comical expression on its face, is a favourite of photographers and is an eagerly sought-after subject in seabird and wildlife photography.
Seabirds like the Northern Gannet, our largest seabird, hunt for surface-shoaling fish by flying overhead until they spot their prey below, then partially folding their wings to form an anchor-like body shape they plunge-dive from a height hitting the water headfirst at a speed that drives them underneath to grab a hard-earned meal.
Puffins adopt a different strategy; they float high in the water on the surface, and when they spot a shoal of fish like sandeels below they upend and dive using their stubby wings to ‘fly’ underwater in pursuit of their prey.
In the current issue of the scientific journal ‘Biology Letters’, a MaREI research team together with the Zoological Society of London, an international conservation charity, carried out a two-year study of foraging puffins off the Saltee Islands in the sunny south-east.
MaREI is the Cork-based marine and renewable energy research, development and innovation centre supported by Science Foundation Ireland. The team comprises internationally recognised experts from Irish universities, research groups and industry partners.
The authors of the report found that instead of the birds swimming aimlessly about in search of food, the puffins drift on the tidal stream and let the current transport them to suitable feedings patches.
A tidal stream is a current associated with tides. Tides cause the water in the sea to rise and fall so the movement is vertical; the tidal stream is the associated horizontal current. Tidal streams usually flow close to the coastline and since they can be quite strong it makes sense that life forms would evolve to take advantage of the free ride.
The authors found that by drift-hunting in this way, the birds save energy that would otherwise be used in looking for prey. Energetic models suggest the cost of foraging trips using the drift strategy is 28–46% less than flying between patches. It appears likely that the birds have evolved to exploit the tidal steam and that the strategy is learned behaviour.
The authors suggest that the drift strategy they observed in puffins may be far more widespread among other species of seabirds than currently thought.
Atlantic Puffins drifting on the tidal stream.