An adult Great Tit is approximately 14 cm in size, has a wingspan of 22 to 25 cm and weighs 17 grams. The great tit has a black crown, white cheek spots and a black belt over its yellow breast. Males can be recognized by the wider black belt and the larger quantity of black between the legs and more gloss on the head. Great tits see each other not like we see them. This group of birds is able to observe UV-light very well, in contrast to humans and most other animals. UV-sensitivity serves to recognize their peers easily, but to be not too conspicuous for predators, which do not distinguish the UV-light. The female of the great tit selects her partner also by UV-light: the more UV-reflection, the better. Particularly the black belt is important in this respect. In addition the male must also prove that he can dance, sing and feed her. The estimated number of couples of great tits in the Netherlands is about 600,000 and is still rising. The average age of a great tit in good living conditions is approximately 10 years.