What are some of the causes of diminishing number of birds?

There are many causes of diminishing number of birds.

Loss of habitat- Due to deforestation many species of birds have lost their natural habitat.

Change in climate- Change in climate due to global warming is another reason for the dwindling of birds. It has been found in a research that many species of migratory birds have got a change in their migration cycle due to sudden climate change in these recent years.

Poaching - poaching and killing of birds for various products is also a valid reason for diminishing number of birds.

Mobile towers- The electromagnetic waves emitted by mobile towers seriously threaten the navigational skills of birds honey bees and is a major cause of colony collapse disorder.