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

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.

1. The first one is- keeping the legs more or less straight, fully spreading the wings right upward, they float their bodies in the air at an angle of 45 degrees with the ground. then they flutter their wings vigourously downwards- which help them to lift upwards in the air quickly.
Look at the Image- 1 to Image - 2.

Image - 1

sequential Image 2

2. The second process is – they utilise the strength of their legs for the initial thrust by first bending their legs to a great extent and fully spreading their wings upwards and then lift their bodies in the air. Then they flutter their wings vigourously downwards- and they move forward. In this case also, their bodies make an angle of 45 degrees with the ground level.
Look at the Image 3 to Image 5
Image 3

Sequential Image 4

Sequential Image 5

3. The third process is – They keep their legs vertically straight, bring the bodyline at an angle of 45 degrees and then flutter their wings with a great thrust in such a way that the extreme end part of the wings move forward to a large extend. This creates a large pressure in the surrounding air and help them to lift their bodies upward in the air. After this, they flap their wings very fast and move forward.

Look at the Image 6 to Image 8

Image 6

Sequential Image 7

Sequential Image 8

4. The fourth process is more or less same as the first one; the only difference is that the bodyline make a narrower angle, much less than 45 degrees with the ground and that after the take off they do not fly very high up in the air and fly close to the ground or water surface.

Look at the Image 9

Image 9

Besides these, I would like to mention here some other general observations

1. In every situation the head and bill always remain horizontal to the earth to navigate.

2. During take-off the shoulder or the inner part of wings work hard. But during flight the only outer part does the main work.

3. Neck and long throat stretch to a large extent so that the Center of Gravity of the body remains in the front as much as possible.

Equipment used - Canon 7D + Canon 500mm f4 + Monopod, photographed from a fishermen boat. All the images posted here is full frame except Image 6.
Photographed at Mathura Beel, North 24-Parganas, West Bengal, September-October, 2015

Critics and Comments are most well come to enrich our knowledge...

Nice detailed record of its flying behaviour. I had seen it taking off many times, but after reading this post I could understand that it does have take-off in different ways. The photographs sequences make it easier to understand how the body structure works for making the take off easier and streamlined. So much aerodynamics involved :). Thanks for sharing this detailed observations.

nice to see an interesting set of images and observations samrat. couple of general observations:

1. Usually the substrata from which the bird is trying to take off will have something to do with the amount pressure put on them for purchase and thrust and the way the legs are positioned at the time of take off . 1 &4 seems to be from a hyacinth bed and 2 from a solid surface.


2. the height and distance sought to be achieved in flight will also change the mode of take off, for example a quick escape will be different from the normal leisurely take off. Also when trying to move only a short distance it will be different from a long flight. 3 seems to be a leisurely take off and 2&4 a quick escape.

TFS
Roopak

Nice observations. .samrat bhai. Good details. Thanks for sharing

Thanks a lot Mrudul ji and Dheerendra bhai for your appreciating comments......
Roopak ji
I agree with you. although lots of parameter is to be included here. such as direction of wind, the height to be achieved ...etc...I am working on that...but it was clear that down-stroke is the main thing to start flying and the bird was following the process no 3 when the vegetation was tall....

Thank you again
samrat