Each year the United States Fish and Wildlife Service (Service), in conjunction with states, the Canadian Wildlife Service, provincial governments, and other partners, conducts breeding grounds surveys to estimate the size of duck breeding populations. Specialized surveys track trends in the populations of other harvested migratory species such as the mourning dove and the American woodcock. The North American Breeding Bird Survey, conducted annually on approximately 2,900 routes in the United States and Canada by thousands of volunteers, is used to follow changes in the distribution and abundance of many other migratory bird species utilizing wetlands and associated habitats.