There are more than 10,000 regional checklists in Avibase, offered in 9 different taxonomies, including synonyms in dozens of languages. Each checklist can be viewed with photos shared by the birding community, and also printed as PDF checklists for field use.
The Blue Tit (Cyanistes caeruleus or Parus caeruleus) is a small passerine bird in the tit family Paridae. The bird is easily recognisable by its blue and yellow plumage, but various authorities dispute their scientific classification. Source: Wikipedia