Deepak,
As Mrudul has suggested, you can pick up a second hand 350D at about 10-15K depending upon condition. For bird photography you need a long lens.

The Sigma APO 150-500 OS HSM is about 50K. If you can get a second hand one, that would be cheaper, but won't fit into your budget. You can buy a new Canon EF 70-300 f4-5.6 lens without IS at around 10-11k. A similar new Sigma lens would cost around 11-12k. You can get started with this kit and polish your skills. Improve your tracking skills, sit in hide and you can get some close shots as well. Later on when you are comfortable, you can upgrade.
Cheers,
Sabyasachi