The Apple Computer centric web site MacNews has a new posting about software for birding and bird watching.
http://www.macnews.com/2010/11/12/category-review-birdingbirdwatching-software-mac-os-x
In addition to these titles there are a number of apps in the iTunes App Store for your iPhone. Some are silly and others are addictive games (Angry Birds). Enjoy.