migratory cranes fly in flocks to southern countries

flock eurasian water fly cranes natural wild flying wildlife crane bird fauna blue flight nature europe group background environment european common animal migrating weather birds habitat gray migratory dawn migrate sky ornithology season silhouette crows wings migration valley out takeoff outdoors flocks southern countries grus also known family gruidae cranes medium-sized species only commonly found besides demoiselle virgo siberian leucogeranus leucogeranus along sandhill antigone canadensis brolga rubicunda one four