I currently use the Panasonic FZ18 as well as a SLR system but a film based body. For more serious bird photography, the FZ18 does not have the resolution or the speed of AF tracking for more than a record picture. From the photographs posted on this site, one can see that a 400mm (600mm in 35 mm equivalent) is often used. Choose either a Nikon or Canon system, either an intro or advance body dependent on your needs. For intro body, Nikon D60 or Canon Xsi while advance body, Nikon D300 or Canon EOS 40D will suffice. A prime lens is more expensive, so a high quality zoom up to 400mm that has internal motor system, Nikon AFS or Canon USM will be suitable. If it offers Image Stabilization or Vibration Reduction feature, it will improve your chance a great deal. Invest first into a good qulaity lens with large enough f-stop for one of Nikon or Canon mount while the body could always be upgraded. Do not forget you may need the flash system and tripod with ball head to compliment the system. For equipment and advise, read from: dpreview.com and photo.net which are helpful. Good luck.
