How to land (gracefully) on a stump

Taking a rapid series (10 frames per second) of high-shutter speed (1/5000 sec) images of flying birds allows one to see just how birds manage some of their aerial dynamics, like how to land gracefully on a small spot.  The test for the birds was to flap-glide-brake from bushes about 25 feet away to land precisely on the edge of a stump feeder filled with delicious suet.

Wings and legs fully outstretched, the Green Jay makes a perfect landing.

What amazed me was that all five species we observed used the same technique:  flap, fold wings in horizontal posture, making them look like a speeding bullet, then brake by spreading wings wide with huge gaps between the flared primary feathers and switching to a vertical posture with outstretched feet.  This is the type of flight used by many small to medium-sized songbirds, often viewed as roller coaster, or bounding flight.

Flap-glide pattern of bounding flight in small birds (Cornell Lab).

Bounding flight like this accomplishes at least two important things:  first, it saves energy, 15-20% over the cost of continuous flapping because of the reduced drag during the glide (closed wing) phase; second, it lowers the cost of flying more slowly between closely spaced perches.

Orange-crowned Warbler bounding flight with wings closed prior to full braking mode of outstretched wings and feet.

Female Hooded Oriole bounding flight. The bird might have changed its mind a little too late to make a totally graceful landing — it was still in bullet shape quite close to the stump.

The Green Jays were masters of this technique, transforming from bullet shape to full braking mode in milliseconds.

Streamlined like a torpedo, then suddenly, full flare of the wings, tail, and feet for stopping short.

I didn’t catch the glide phase of the Golden-fronted Woodpecker as it made its approach. A full flap, then glide, then landing was this male’s approach like all the other species.

Not every approach to the stump was completely graceful, but birds are such adroit athletes, even being slightly off-balance on approach can be immediately corrected.

Can you just imagine the alarms going off in the bird’s brain as it makes sudden changes in its approach for landing?

Graceful