Eurasian Blue Tit Flying In And Out Of The Nesting Hole On Tree Trunk

blue tit cyanistes caeruleus eurasian nesting hole tree trunk nest hole close up natural nature eurasian blue tit wildlife bird tit wild animal outdoor bark feather nest forest cute ornithology cyanistes beak plumage green birdwatching closeup birds spring caeruleus blue titmouse small springtime warbler fauna passerine feathers birdie habitat hollow cavity wood species nat geo landscape