It is very very rare
The cow bird. The cow bird lays it's eggs in another birds nest, and then when the cow bird's eggs begin to hatch, the baby cow birds will push the other birds out of the nest.
Cuckoos do this.
Flamingos are birds, they lay eggs in a nest that they have prepared for it.
In a nest
No. they lay eggs in their nest
Cuckoos and cowbirds are famous for laying their eggs in other birds' nests, and leaving the chicks to be raised by the other birds.
The female Common Cuckoo lays her eggs in other birds nests, like the Reed Warblers and Willow Warblers nests.
why do all birds build nest
Most birds nest their eggs. The material from which nests can be constructed depends on the species of bird and the materials available in the area. Robins and eagles are both well known species that nest their eggs.
When birds build a nest the then lay "eggs" in it. The eggs hatch into baby birds and the adults feed these until they are big and strong enough to fly off the nest.
mostly
Scientifically it's called "brood parasitism". The most well-known example of this type of birds is the Common Cuckoo. This is also the origin of the words "cuckold" and "cuckoldry".