At the end of the days after completing all our household chores and just before retire to our beds most of us will admit that we cherish the habit of a lengthy yawning. But why only before going to sleep, we often do that when we feel a little relaxed in between spells of hectic periods. And we do that involuntarily. For us humans it is very common to yawn. Not only humans, the apes, monkeys, lizards, tortoises and even some birds also do yawn regularly.
Earlier it was not so easy as the ease with which I declared that the birds also do yawn because the ornithologists did not even think of the birds yawning!
The celebrated ornithologist Heinroth carried out some research works on the changes of behaviours among the different species of the birds. For many decades after that he has recieved many accolades for his contribution in the field of ornithology. The impact of his works was so impressive among the ornithologists that his observations spoke the last word regarding the behavioural studies of the birds. Interestingly, he did not believe that the birds also yawned. And everybody agreed to his views in this regard
Though there have been many research work done and many articles published about yawning in human, no such work has been done worth mentioning about yawning in other animals, mainly among birds. In the year 1967 two ornithologists E G Franz Sauer and E M Sauer published their research paper in the famous ornithological journal, The Auk and in that paper they demanded that the birds do yawn. They conducted their research work on ostriches in the deserts of Namibia, Kalahari, in Erongo Mountain and in Etosha Pan from 1957 to 1958 and in 1964.
I was observing an Asian Openbill Stork in the Mangalajodi wetland in December previous year. It was very close to our boat and was cleaning its feathers with its beak unafraid of our presence. We know this behavior of the birds as “preening”. Some of the very common habitual practices do not generally come to our notice and goes unheeded. Preening is one such behavior of the birds. In the cases of the birds this habit is considered as their comfort behavior.
Simply speaking, during the time the birds feel at home with their surroundings and do not feel any threat from anywhere around that is the time they perform a comfort behavior like this. The bird I was talking about was doing just that and at the end it was standing on one of its two legs. Then it started rubbing its back with the hind portion of its neck.