Minnesota Birdsong: An interactive poster Cute interface with birdsong content provided by the always amazing Cornell Lab of Ornithology.
NestWatch offers all kinds of interesting information about birds and their nests with beautiful pictures of the birds, their nests, clutches, broods, and fledglings. An example: the Indigo Bunting. Each page about a particular bird includes their often beautiful songs and sounds. There is a related Flickr NestWatchers site, as well as an extensive community with links about places for bird watching in each state. It's part of the fabulously encyclopedic website of the Cornell Lab of Ornithology with its own rich archive of superbly organized recordings and videos at the Macaulay Library. [more inside]
Because there are so many birds around the world, and because they often look very similar, you likely need a field guide to help you figure out what bird is in your backyard. Well, just in time for spring, the Cornell Lab of Ornithology has redesigned their wonderful All About Birds site and they can help you with building your skills. Don't forget to bring your checklist!
RavenViewer. The Cornell Lab of Ornithology offers free sound analysis software that allows you to simultaneously listen to and watch spectograms of animal communication, such as the uncanny mimicry of a lovesick Satin Bowerbird or the chilling call of the Common Loon. If birds aren't your bag, there's lots of other animal sounds (and stunning video) to explore.
The Cornell Lab of Ornithology is a great source for all kinds of information on our feathered friends. The bird identification section is particular useful. There are also NestCams.