The xenon-canto API allows developers to access information on 8,244 bird species, including over 100,000 recordings of bird songs available so far. Over 20,000 recordings are added each year. However, they say this is a long-term project, with an estimated 2,000,000 recordings needed for a complete record. At current rates, recording them all would take over 140 years.
The webpage about the API shows how to link to recordings and embed them in your website(s).
The homepage contains a rolling news blog on the latest recordings collected. And, like many birders, these people are dedicated. One blog entry reads,
"02-09-2012. Andrew Spencer has shared his 2000th species on XC, a Black Skimmer. Nearly all of his 5000+ recordings are top quality. Incredible."
Another webpage on the site shows how you can be a participant in recording calls. You can even get a ranking of who has collected the most recordings, the most species, and the number of species contributed only by that recordist. (Top dog is Frank Lambert, with over 6,500 recordings of over 2,300 species, of which 205 are unique contributions to Xeno-canto.
The screenshots below for the Yellow-olive Flatbill Calls show some of the information available: a visual representation of a bird call followed by what is offered by the options link: a list of subspecies plotted on a Googlemaps.
Attention birds: xenon-canto has a "species wanted" sign for additions to the database; apply within.
Founded in 2005, the website is run by the Xeno-canto Foundation headquartered in the Netherlands.