Final answer:
Birds are classified as either long-distance migrators or medium distance migrators based on the distance they travel during migration. The classification is subjective and varies depending on the species and region. Migratory distances can vary widely among bird species.
Step-by-step explanation:
Birds are classified as either long-distance migrators or medium distance migrators based on the distance they travel during migration. There is no specific migratory distance that defines a bird as a long-distance migrator. This classification is subjective and varies depending on the species of bird and the region they inhabit.
For example, some birds that migrate a few hundred miles may be considered long-distance migrators in certain regions, while in other regions, they may be classified as medium distance migrators.
It is important to note that migratory distances can vary widely among bird species. Some birds, such as the Arctic tern, migrate for as long as 44,000 miles round trip, while others, like the American robin, migrate around 2,500 miles.