Overgrown Nail Symptoms: Without proper perching materials claws/nails will not naturally wear and will become overgrown. Overgrown nails will prevent the bird from being able to perch. They could also get stuck and bound in nesting materials and can die from being hung upside down.
Causes: Poor variety in perches. No natural wearing of nails.
Treatment: Cut the claws with sharp scissors. Pay attention not to injure the blood vessels. (The dark areas of the nails) To prevent further issues with overgrown nails provide a variety of thick and thin branches in the aviary or cage. This will assist in natural wearing of nails.
Pet Bird Care Us magazine, Common Finch Diseases: Aries Munandi, June 2015