Question

What will happen to environment if there are no birds

Answer 1

if birds get absent in the nature  there will be no pollination if there is no pollination there are less chance for flower to grow and bare seed and gradually the trees in environment decreases  

i hope this helps you

Answer 2

See, birds are a part of food chain, these animals making the environment or there habitat balanced. If there would be no birds the entire ecosystem system will get unbalanced like the balance of gases on the earth's atmosphere!!!
No prey would get proper food chain which will effect the ecosystem as well as our environment.