What is "whiffling"

Whiffle \Whif"fle\, v. i. [imp. & p. p. Whiffled; p. pr. & vb. n. Whiffling.] [Freq. of whiff to puff, perhaps influenced by D. weifelen to waver.]

1. To waver, or shake, as if moved by gusts of wind; to shift, turn, or veer about.
   --D?mpier.

2. To change from one opinion or course to another; to use evasions; to prevaricate; to be fickle.

   A person of whiffing and unsteady turn of mind can not keep close to a point of controversy.
   --I. Watts.

vb. (present participle of whiffle English)

Whiffling is a term used in ornithology to describe the behavior whereby a bird rapidily descends with a zig-zagging, side-slipping motion. Sometimes to whiffle, a bird flies briefly with its body turned upside down but with its neck and head twisted 180 degrees around in a normal position. The aerodynamics which usually give a bird lift during flying are thereby inverted and the bird briefly plummets toward the ground before this is quickly reversed and the bird adopts a normal flying orientation. This erratic motion resembles a falling leaf, and is used to avoid avian predators or may be used by geese ( family Anatidae) to avoid a long, slow descent over an area where wildfowling is practised.

The behavior is seen in several species including lesser yellowlegs (Tringa flavipes), the black-tailed godwit (Limosa limosa), the northern lapwing (Vanellus vanellus), geese (e.g. pink-footed goose (Anser brachyrhynchus)), three species of scoter (Melanitta), and other members of the family Anatidae.