The Atlantic Puffin has a face that has launched over 1,000 ships full of wildlife photographers and bird lovers. But the puffin is more than a pretty face.
By Rex Graham
Scientists are most amazed by an overlooked feature of this glamour species – its wing.
The Atlantic Puffin wing
Andean Condors have perfected the biggest, Bee Hummingbirds the smallest, but puffins have a marvelously efficient in-between-sized wingspan of 550 mm (21 in). It is one of the bird world’s most ingenious marvels of bioengineering.
The innovation is tucked out of sight when the short stocky birds pose for photographs. Most lenses are focused on the hatchet of a bill ribbed in blues, yellows and orange stripes. They are indeed gorgeous. Their performance engineering is evident when they become airborne.
Built for speed
Puffins look like equal parts bumble bee, penguin and racing pigeon.
Puffins beat their wings very fast – 400 beats per minute, and attain a 55-mile-per-hour (90 km-per-hour) cruising speed. Racing pigeons average 50 mph. Puffin wings are a blur as they zoom to and from their fishing grounds.
But bumble bees and hummingbirds don’t swim. The puffin wing does double duty, dry or wet.
Scientists have been surprised by how puffins do it. Loons, grebes and diving ducks are no match. They propel themselves underwater with their webfeet, not wings.
Smaller, better, faster wing
Puffins’ smaller-than-normal wings are analogous to penguin flippers.
Puffins opt for speed over agile in the air. They fly to fishing grounds, often 50-100 km (30-60 mi) from their colonies in an hour or less.
Puffins’ flight muscles are special. The pectoral muscles that power each wing down stroke look anatomically like those of racing pigeons, but there are biochemical differences that give puffins an advantage while swimming.
Surprisingly effective upstroke
A puffin’s upstroke is significantly faster than a pigeon’s. Small wings and faster upstroke enable faster wingbeats and higher speeds. Racing pigeons and other flying birds also need an upstroke, but they invest far more muscle mass on the down stroke.
The upstroke muscle (called the supracoracoideus) is only 1.6% of the body mass of a racing pigeon. It’s 3 times larger in puffins. Scientists now know why: “It most likely evolved to raise the wing against the resistive drag of water,” said Christopher E. Kovacs of Brown University and Ron A. Meyers of Weber State University in the Journal of Morphology.
The upstroke was thought to slow the birds slightly in preparation for the next down stroke.
Swedish researchers discovered that puffins’ upstroke helps maintain their swimming speed. “Our results clearly show that the Atlantic Puffin can use an active upstroke to gain thrust while diving, in contradiction to previous suggestions,” researchers at Göteborg University said in the Journal of Experimental Biology.
The end result is a master aerialist and pursuit predator of fish. Puffins, murres and auklets are Northern Hemisphere equivalents of penguins that fly. Murres and auklets also “fly underwater,” but Atlantic Puffin’s are better.
Kovacs and Meyers have made key discoveries about how puffins swim so efficiently. The birds actually change the shape of their wings while extended underwater. “Puffins are able to reduce the effective wing surface area underwater by ?exing the elbow and wrist joints to reduce wing span by approximately 50%,” Kovacs and Meyers said.
Flight-muscle biochemical enhancements
There’s more. Puffins have fined-tuned the biochemistry of their flight muscles. They have both fast-twitch fibers that are most helpful while flying, and slow-twitch fibers with greater ability to perform while the birds hold their breath.
This hybrid biochemistry provides a unique blend of speed and endurance. It explains how they can fly so fast to feeding grounds and pursue fish so effectively on their dives as much as 75 m deep. Kovacs and Meyers said puffins are “unique organisms adapted to a dual-medium lifestyle.”