Respuesta :
The branch of biology which deals with birds is called ornithology. It describes the nature and the behaviour of the bird.
Over the years the population of birds start decreasing due to overexploitation.
The reason why the population of birds reduction are as follows:-
- Invasion of the alien species
- Overhunting
- Land fragmentation.
Therefore, the main cause of reduction in bird populations is Land development.
For more information, refer to the link:-
https://brainly.com/question/15889243