Migration Surveys
Some population surveys are conducted during the spring and autumn migrations, such as the Mid-continent Sandhill Crane Survey and the Fall Inventory of Mid-continent White-fronted geese.
Mid-Continent Sandhill Crane Survey
Nearly the entire population of cranes gathers in Nebraska’s Platte River Valley during spring migration. A pilot-biologist and observer count birds along established transect lines. Aerial photography of a sub-sample of crane flocks is used to quantify errors and develop correction factors to obtain a more accurate population estimate. A Status and Harvests of Sandhill Cranes report is produced each year.
Cranes on the river during survey. Jeff Drahota, USFWS
Cranes still on river at 10 AM. Jeff Drahota, USFWS
White-fronted Goose Survey
Another example of a migration survey is the Fall Inventory of Mid-Continent White-Fronted Geese that is conducted every September in the Canadian prairie, where the population gathers during the southward autumn migration.
A White-fronted goose on the Tule Lake National Wildlife Refuge. (Credit: David Menke, USFWS) David Menke, USFWS
