Doug - I won't repeat any arguments, because I hear/have to stand these discussions every day: esential is the fit of sensor and lense, that means f.i. a Nikon-compatible DSLR will give best results only with the best (and that means generally prfessional/expensive) Nikon lenses (replace Nikon by Canon and you get the same); if you have old lenses which were good for film, they will most likely not satisfy you with a digital camera (that's what sales people usually do not tell). My actual images are made with a Fujifilm S7000 - works pretty well but has limitations. With your bird images you'll need a good tele lense and perhaps an image stabilisator (Panasonic). If I was free I'd take a Fujifilm S3 Pro with an excellent Nikon lens (probably 2) (2.000 EUR + lense + accessories + ...)

Gerald