So they can survive from their predators, who live on ground.
In trees
penguins
cause they are really high
In tropical rain forests it is found as epiphyte on trees. Since the older leaves of this fern form a nest like structure it is called Birds' nest fern.
They give many birds and animals a safe place to nest and raise there young.
erm, do you mean the random event type birds nest. These happen when wood cutting, particularly the maple and yew trees near Seers village and Catherby
Your answer relies on asking WHICH birds nest WHERE: Some birds nest out in the open, right on the ground, such as ducks, gooneys and penguins. Some nest on desolate islands, such as the albatross and the blue-footed booby. Some nest INSIDE of trees, such as the woodpecker, and some nest HIGH in the trees, such as falcons, hawks, and eagles. The rainforest (like the Amazon) has three layers of canopy in which various birds nest. Ptarmigans nest right on the tundra. You could step on them if they didn't jump up and fly away right before you do so.
The larger the bird, the larger its nest.
No. Some birds nest on the ground (curlews), some (woodpeckers) make holes in trees and some lay their eggs in other birds nests (cuckoos).
to keep their babies out of danger and also trees are high enough so that the mother can teach them how to fly you AIKALO !!
no, unless you want to turn into a tree person and have birds nest in your hair.
Since there is not unlimited trees to make nest in, I'd say they do compete for shelter.