At least 4,000 birds are migrants at some point or other; that's 40 percent of the world's bird population, says the Audubon Society. Of those busy birds, it turns out that their approaches to re-fueling and taking breaks during the trip are different, bird by bird. These differences have to do with flight length, says a recent study reported in the journal Animal Migration.

The study, led by Tulane University, looked at three shorebird species: semipalmated sandpipers, western sandpipers and dunlins. Respectively, one of those makes short flights interspersed with stops in between; the next flies for long periods and stops only once or twice; the third species is in the middle of the other two, according to a release.

The researchers captured these birds along the Gulf of Mexico and measured their pause times and rates of refueling. From this, they concluded that birds going the long-haul distance stayed for longer periods at the sites where they refueled; those birds also put on more weight, faster, than short-distance travelers. The "in moderation" birds that made short flights had shorter feeding visits and gained less weight, the release noted.

Shorebird stopover sites throughout the migratory flyway are slowly dwindling due to habitat losses, and this information can help to predict the impact of such losses to different bird species and develop conservation plans to mitigate these impacts," said Andy Davis, Editor-in-Chief of the journal Animal Migration, the release confirmed.

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