The pictures above and below are of a goose performing an upside-down contortion as it battled to land in heavy winds. The bird was captured by a wildlife photographer flying with its neck twisted 180 degrees and its body seemingly facing the wrong way. The bird, a greylag goose, was photographed as it came in to land on a freshwater lake. (See articles here and here).
The maneuver is a tried and tested way of braking, called whiffling.
The aerodynamics of bird flight are similar to those governing a plan, with lift created by the curved shape of the wing combined with velocity. This creates an area of low pressure above the wing and high pressure beneath it, creating upwards force.
But Mother Nature has also provided birds with the ability to decelerate swiftly by turning over their wings to "spill out" the air, a maneuver known as whiffling. According to ornithologists it makes a bird "drop like a stone" so that they instantly lose height.
Some ducks and wading birds such as black-tailed and bar-tailed godwits and pelicans are also known to whiffle.
Below is the bird's "landing sequence":
The additional image below, taken from here, shows a group of pink footed geese in various stages of whiffling:
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