eBird by Cornell Lab

eBird Mobile makes it easy to record the birds you see in the field, and seamlessly link these observations with eBird--a global online database of bird records used by hundreds of thousands of birders around the world. This free resource makes it easy to keep track of what you see, while making your data openly available for scientific research, education, and conservation. eBird Mobile is the only app that passes information directly from the Android device to your eBird account on the web. Features

- Track your bird sightings from anywhere in the world.
- View your Life, Year, and Month lists for any region or nearby location.
- Full global taxonomy based on The Clements Checklist of Birds of the World.
- Common names available in 41 languages and regional versions (e.g., Portuguese names in Brazil or in Portugal).
- Checklists customized for your location and time of year, showing most likely species based on eBird data.
- Real-time feedback on whether a sighting is rare in the area.
- Quick entry tools to make note-taking faster than ever before.
- GPS enabled location plotting and tracking options.
- Map tools that show you hundreds of thousands of eBird Hotspots.
- Full offline functionality, enabling use in places with limited or no Internet connection.
- Entire app translated to Bulgarian, Czech, Danish, German, Spanish, Finnish, French, Hebrew, Croatian, Khmer, Norwegian, Dutch, Polish, Portuguese, Russian, Serbian, Swedish, Thai, Turkish, Ukrainian, Chinese (Simplified), and Chinese (Traditional).