Las Aves de España

This is quite likely the most complete app for the birds you will see in the Iberian Peninsula. Given that it is done by Spain's official ornithological society, the content is quite good: descriptions, maps, sound, photos, videos. Top itineraries is also a very handy feature. Minor issues are that, for example, sorting by "families" will not let you truly scroll all the way to the bottom of the list, and I can't understand at all why, having just released a nice new logo, SEO preferred to use the photo of an owl for their app icon, instead. It looks rather ugly next to my other apps. Also, I'd encourage future integration with a modern listing platform, like eBird, but the SEO still hasn't caught on to the practical value of this.