Birdr is a free, open-source bird-identification training app for birders worldwide. Available on iPhone, Android and the web, it helps users improve their ability to recognise bird species through interactive quizzes, personalised practice and country-based challenges. Players can choose short or extended games, select a country and difficulty level, and answer questions using photos, video or sound recordings.

After each quiz, they can review their answers and practise species they missed. My Tricky Birds offers focused drills on lookalike species and birds that users find difficult, while personal checklists track which birds they have identified correctly in a chosen country. Birdr also provides live multiplayer quizzes, high scores and browser-based play, including passerine sound quizzes.

Its Country Challenges offer structured learning across species found in countries around the world. Birdr is built in spare time and has no current funding; community members can contribute feedback or review photos, and supporters can help with hosting and AI costs through sponsorship or explore partnership and grant opportunities