What determines the Flight Paths of Birds?

What determines the Flight Paths of Birds?

The long drawn out trade Union Action gave me some free time to watch bird migration. This year the weather pattern was bizarre and in keeping with that the birds that came in also differed in type if not numbers. Numbers never approached the 30 which I used to count 30 years. Numbers have come down to 3 to 5 and only fluctuation was seen in the migratory birds. Unsusal finding was there were three types of woodpeckers. The common one without a distinct crown feather with a big beak. Another tiny woodpecker (not young ones) and the third was exotic hooded varity very beautiful. All of them were looking for nesting site and were exploring the bread fruit tree for boring holes. They came for about three days and vanished. I am fortunate but (birds are not and their flypath is now interrupted by rapid development and there is no food or water. surface well that the birds came was closed in the name of development and the little stream is dry now.

What determines the Flight Paths of Birds?

We can assume they migrate in search of food, nesting site and to avoid the harsh winter condition but what determines the flypath?

I wondered and wondered. We have not done adequate studies to postulate any firm scientific theory. I developed a theory based on simple observation. All the birds hate rainclouds. Not only clouds interfere with vision but the cold weather fronts and lightening must surely be frightening to the birds. My observation is relate to the movement of clouds. The clouds h the Hanthana range and breaks into basically two paths. One goes towards Kandy and the other towards Katugastota. Usually one dominate the other. If the clouds come down towards Panideniya it is very likely the clouds will go towards Katugastota. If it does not but hit the Peradeniya Botanical Gardens it will move definitely towards Kandy. All these are very simple observation and nothing extravagant and I see them and avoid the rain especially when I do not carry a an umbrella.

There is a corridor of no clouds and the birds often get it right and come well in advance of the rain in this corridor. No rain or thin drizzle the birds are their in numbers. Heavy rain of course no birds and the local resident birds get out of the way well in advance.

This of course is a very simple observation but I really do not know why these birds take a particular pathway. This is something I will study if I find time or in my retirement.

One thing is sure if we make radical change to the tree cover in the name of development the birds I see now will be never seen again on the same route.