Mechanism behind the "Take-off" of Grey Heron (Ardea cinerea)

[Samrat Sarkar]

Since the last few weeks I have been working on Grey Heron (Ardea cinerea). I am especially trying to understand the mechanism behind their take-off. Normally, the whole phenomenon of flying of any bird can be differentiated in various stages. The initial stage is obviously the “Take-off”. And this is followed by climbing, diving, bounding, gliding, soaring, hovering and lastly, landing.
In fact, flying is obviously a unique power of the birds which had to be achieved through the struggle of millions of years. Birds fly for different reasons. They fly for escaping from predators and other dangers, for finding and grabbing food, for migration etc. The first stage of flight is Take-off. It is very important for any birds because a steady and perfect take-off reach them into a perfect flight.
Grey Heron can take-off from shallow water, wetland reed bed and floating hyacinth or from other vegetation too. It is a wonder how such a tall bird weighing just over 1 Kg can take-off in a fraction of second.
All the birds which live close to different water bodies do not take-off in a same way. Ducks and cormorant fly directly from the surface of water. They initially run over the surface of water and flap their wings fast on water for initial lift. Then they achieve frontal velocity in air by fast upward and downward stokes of their wings.
Grey Heron does not follow the process that ducks do. They have two long legs. Dr. Salim Ali wrote in his book about take-off of Grey Herons in details. “The initial take-off from the perch is clumsy and accompanied by an awkward stretching of the long neck, vigorous labored flapping of the wings, and by much swaying and balancing with the long loosely dangling legs. The launching is preceded by a slow swing or waggling of the tail up and down, as if to assist in the process. The bird then flexes its legs and springs upward. Once in the air it flies strongly with steady flaps of the broad wings, neck characteristically folded back in a flat ‘S’, head drawn in between the shoulder, legs trucked under the tail and trailing behind.”
Here are some of my observations on their take-off with some sequential photograph. i have observed mainly four types of take-off.