Garden Wildlife: Green Finches Green finches are common garden birds with big triangular bills. Bright yellow and olive green, they are sociable and come to feeders and bird baths in towns and in the country. They eat seeds and insects. Chaffinches are also common finches.ALERT: both types of finch and some other birds are being infected by a disease-causing parasite which weakens them and stops them feeding. The parasite is spread at infected feeding stations and bird tables. Major birding organizations recommend that we clean our bird feeders and tables frequently, once a week as a minimum, and soak them in a weak bleach solution to halt the spread. If you see diseased birds, it may be better to stop feeding for a number of weeks (there are lots of wild sources of food at the moment) and do a thorough clean. Don’t allow children or pets to handle diseased birds.