SNP is spread over an area of about 1.43 square kms and has always been a safe haven for both resident and migratory birds. It was declared a Bird Sanctuary in 1972 with the efforts of Sir Peter Jackson, a renowned ornithologist and then Prime Minister Shrimati Indira Gandhi, who was pivotal in the inception of the Bird Sanctuary. Later in 1989, the status of the park was upgraded to that of a National Park.

Historically, over 300 species of birds have been sighted inside the sanctuary. Every year in winters, SNP floods with migratory ducks and other birds between October to March. In view of this, it is one of the most ideal locations for birdwatchers in Delhi NCR. A lot of foreigners passing through the area during this time, make a mandatory stop at the park for a little dose of birdwatching and have never been disappointed.

SNP is a good mix of both wetland and woodland habitat so birds favouring both habitats can be seen inside the park.