Monday, June 18, 2012

Feathers for the Swallows

dead swallow and goose feather
Violet-green swallow on a big feather that he may have carried up to feather his nest if he hadn't crashed into a window.

A huge bag of goose feathers stands by my front door for the swallows.  They use them to line their nests.  When the swallows arrive in spring migration, they begin to build the nests and are on the lookout for materials.  In May and June, if it isn’t raining, I grab a handful of goose feathers from the bag every time I go outside.  Feathers scattered on the ground attracts barn, violet green, and tree swallows.  But they prefer to catch floating airborne feathers rather than swooping down face-first to grab them off the earth.  So I blow feathers from a ten-foot plastic pipe into the air for the birds to snap up.  The birds soon learn what I am up to when I pick up the pipe: they fly around and around, waiting for a feather to come out.  I notice that from the beginning to the end of the season, their feather catching skills improve.  They learn to grab them by the fluff at the front of the shaft and fly with them curved underneath their bodies.  So I give them bigger and bigger feathers, even larger than the ridiculously large size of the feather pictured under this poor bird that crashed into a friend’s window.    

Monday, June 4, 2012

Why Feathers Are Curved Part 2


argus pheasant feathers
Great Argus Pheasant wing tip feathers
A mix of side-to-side and front to back curve feather curve lets each kind of bird fly in their own special way. 

How a feather shaft is shaped depends on what type of flight is important:
·         quick but short bursts of flight like seen in pheasants and a lot of songbirds. The first primary flight feathers of these birds are super-curved from side to side but not so much front to back.  This makes for a quick lift-off.  Think of a forest grouse that explodes off the ground, usually scaring the bejeezus out of anyone close by. 
·         soaring flight like vultures and eagles. The main flight feathers have some front to back curve or camber.  My sister showed me a huge Wood Stork primary feather from Tanzania that had so much front to back arc camber that five of them would make a full circle. 
·         Fast flyers like swallows, ducks, and falcons or gliders like seagulls.  Their feathers usually have less curve both side to side and front to back. 

Other aspects of wing flight feathers like their shapes let them do what they do in flight.  Which is a good subject for an upcoming series of blog articles: shapes of feathers.
There is way more to flight feather curves than what I have outlined here.  A good source to start with is the 2010 book, Bird Feathers: AGuide to North American Species by David Scott.