There are many great places to take shots of a bluebird during nesting season (over by now). Keep any eye out for nesting boxes. I have found that patience, lighting and persistence have the greatest impact on getting a good shot. I am using a Panasonic G1 and 100-300mm lens for all of my shots. Probably at the low end technology wise but very portable with good length (600mm at 35mm equivalent). I rarely go above ISO200 and have been using a cheap monopod.