Seasonal migration of birds

One of world's leading experts on endangered species is David Wilcove. He wrote a book about migrations of birds and in poor words he thinks, migrating birds have not way home.

I know about this problems from the times I live in Italy and so wanted to look for more information around the internet.

There are many problems that have birds in their migrations ad the main of them is the human activity. Changes that human make on the roads of migration. So some persons thought to change this situation and to help the birds. Somebody builds houses for birds others think to cover lights over New York. Somebody wants to prevent seasonal migration (India)


In Italy, I hear about it every year, the hunters know that those are last existing individuals, but shoot them. And the persons that protect the birds too (Sicilia). In other places people understood what they lose only when the swallows don't came in spring more. Really sad.
Here where I live we see sometimes the birds flying over our heads. And there are zones of protection too. But how to do that poor birds know, where to go?

Did you know it?
One.The birds have different types of migrations. In spring they go in the places where they will make the family. After the nestlings are ready to fly, the birds can "wander" from place to place (and there are birds that pass their life "wandering"). This can help them to create the unite storm for migration too. And finally there are autumnal migrations to the warm and reach on food in winter places.

Two.There is a science, named phenology that studies seasonal changes in the nature. Like when this plant opens it's flowers and why?For ex. swift (on the photo) comes in Kaluga/Russia 2 weeks later as befor.