What features of a camera make it good for bird photos

I would second just about everything posted in HelloBirdy's prior thread. Good advice there! (Good luck with the P610, HelloBirdy. It seems to be a first choice for a lot of birders. ).

Have you had much experience with cameras thus far? There are definitely factors which make some cameras better for birds than others, but there are also factors which make some cameras better for certain users than others.

If you're just starting out, your first decision should be whether or not you are comfortable with the idea of interchangeable lenses or not. For fast focusing (think birds in flight or zippy little honeyeaters etc) a DSLR with a good quality lens will generally give you better results due to their better autofocus than compact cameras. Their bigger sensors will also generally give better image quality when the light isn't so great or conditions are otherwise bad. They're going to be bigger, more expensive and more complicated, however. Lens selection will be as big a factor as the camera body itself, if not bigger. $2000 would probably involve looking at used gear or making some compromises on the features of the camera body and/or the quality and reach of the lens (or both). You may want to factor in a tripod or monopod for some of the bigger lenses out there.

A bridge or superzoom type camera will be smaller, lighter and cheaper (think maybe between a quarter and a half of your budget). They're also going to give you the most zoom, as their small sensors give you a much more "zoomed in" field of view through the lens. But it generally won't be up to par with an interchangeable lens camera otherwise. A bridge is a good place to start as you'll be able to take it everywhere with you and zoom right in on birds from far away, lessening the need for extra hours spent getting closer to the birds. Great for record shots and identification, but on occasion you'd be up against it trying to get a really stunning image. 

Modern mirrorless cameras (interchangeable lenses, but smaller than DSLRs) can sometimes give you a good combination of features, or a compromise between all of the above, but there's no such thing as a free lunch!

I agree in principle with what Detritus said.  The camera is not the most important item it is the lens you are going to use.  Generally a 300mm telephoto lens is the entry for bird photography. The cheap kit lenses are OK for general use like landscape but telephotos are in a different world. The bigger the minimum aperture the better but the cost can go ballistic. Generally the price range the average person goes for is less than $1500 and these have a minimum aperture around the f5.6 to f6.3.

Most DSLRs with the small sensors (crop factor lens) has a crop factor of around 1.5 meaning the 300mm lens acts as a 450mm lens. The expensive full frame cameras with the 35mm sensor doesn't have the crop factor however they can be programed to behave as if the do.  Full frame is the way to go and the reasons are too complicated to list here but they are outside the price range of most amature photographers.

When photographing birds use Aperture priority if the birds are perched or relatively static and Shutter priority if they are moving quickly as in flight.  To freeze a birds wing in flight you could well go up around 1/4000 second shutter speed so you will need plenty of light or a high ISO and this is where full frame cameras come in as they can go up to very high ISOs where a crop factor camera starts getting digital noise at around 800 ISO

I hope this helps,

Doug.

 I won't recommend any brand as that is a personal decision. 

Very good AF

Burst speed of around 10 fps or more

Buffer of around 50 frames or more

Large clear viewfinder

Light weight if shooting hand held

Mirrorless have a number of advantages such as blackout-free shooting. If BIF are a priority this will reduce the learning curve a lot.