Clubbing is an enlargement of the ends of the fingers and a downward sloping of the nails. Although it's not caused by chronic obstructive pulmonary disease (COPD), it can be a sign of coexisting lung cancer or other lung disorders in patients with COPD. Clubbing is sometimes called digital clubbing. It can affect the fingers and/or toes.
Relatives. Darwin's finches can be divided into groups based on beak type. There are three species of tree finch: the small tree finch, medium tree finch, and large tree finch. Tree finches have grasping beaks.
All true finches belong to the family Fringillidae, but many types of pet birds from other families have the word finch in their common name since they look similar to the true finches. Two of the most commonly kept pet true finches are Zebra finch (Poephila guttata) and Society finch (Lonchura domestica).