The 2009 crop of birding-related offerings for iPhone & iPod Touch is off to a very strong start with the release of Raptors by Natural Guides, LLC.Jerry Liguori, one of the top raptor authors and ID experts in the US, provided the knowledge and images that make this a fantastic portable reference for 19 of the most common raptors (and vultures) that occur in the US. After the gorgeous Golden Eagle closeup on the startup screen (at right), the app takes you to a listing of the featured species.Clicking on a species takes you to a page with text information about the bird (overview, plumage, size, call description, habitat, prey, nesting information, and trivia.) There are links to images (the program features over 200 photos), sound samples, and range maps for each species. The images are zoomable, but not rotatable to landscape format (an enhancement that would be nice.)There are a couple other features beyond the guide functions to mention, too. First, there is a quiz generator with images, sounds, or trivia questions. There's also a checklisting function to record your raptor sightings.The current iteration of the app has a few little bugs- sometimes it quits without apparent reason and there are a few little typos that I've found, but I anticipate these will be addressed in future updates. Perhaps they'll round out the list with the rest of the regularly occurring North American raptors, too. Especially across the southern part of the country, many interesting & sometimes fairly common species (like Harris's Hawk and Crested Caracara to name a couple) should really be included to make this a comprehensive guide. I'd hate to think that someone new to observing raptors would get stymied by something fairly common in many areas like Mississippi Kite just because it wasn't listed in this app. Still, I think this is a harbinger of more to come for iPhones and other smart phones and mobile computing devices, and I anxiously await the next "guidebook 2.0" to drop.