Some Canada geese, usually migratory birds, have settled in Fairfax County and are fouling streams and fieldsand forcing the county to pay for an expensive cleanup, officials said.

The rise of home developments that include water features, such as ponds, and the lack of hunting pressure have allowed some Canada geese to set up a permanent habitat in the county, said Charles Smith, natural resource specialist with the Fairfax County Park Authority. Some of the geese, he said, were raised locally in captivity and have no memory of migration.