Looking for a lense for my camera?

I'm in searching for the right kind of lense for my camera. I have a nikon D5000 and need a portrait lense and some kind of telephoto lense for taking shots of birds or in my case buffalo and things like that. I don't know what modle or anything like that.could you please help me?

Try online web sites. I'm sure they can provide

The Nikon AF-S 70-200mm f/2.8
http://www.bhphotovideo.com/..._2_8G.html
that would be best, and would be good for both types of photography you want to do

if you want a cheaper, two lens solution, the 50mm f/1.8G or f/1.4G (the ideal portrait focal length for APS-C cameras), or if you don't mind standing back a bit more, the 85mm f/1.4G (the ideal portrait lens)

and the 55-200 or 55-300mm lens

50mm: http://www.bhphotovideo.com/...4261208119

85mm: http://www.bhphotovideo.com/..._1_4G.html

55-200mm: http://www.bhphotovideo.com/..._AF_S.html

55-300mm: http://www.bhphotovideo.com/..._5_6G.html

If you already have the 18-55mm kit lens, that should be enough for portraits. If you want to easily blur out backgrounds, get the lowest f/numbered 50mm lens you can afford. For taking buffaloes up close, I recommend you get at least 300mm. If you want to combine portraits and wildlife in one lens, then get something like 55-300mm or 75-300mm.

http://keerok-photography.blogspot.com/2011/05/lenses-so-many-of-them-there-is-no-best.html

Wildlife, 300mm is minimum, more is better. Cheapest quality way to get to 300mm is nikon's 55-300. If you do get more serious, Sigma makes a 150-500.

Portraits, a 50mm f1.8 AF-S will do nicely for headshots and moderate distances.