Searching for [red bird] shows good results, but you can still find some unrelated images. What if you search for [bird] and restrict the results to red images? Here's the URL:
http://images.google.com/images?q=bird&imgcolor=red
(you can replace "red" with "blue", "green", "teal", "purple", "yellow", "orange", "pink", "white", "gray", "black" and "brown")
You can try the new feature using this simple drop-down:
