“[T]he species may not actually need to land for sleep”

NPR – The Two-Way: This Bird Can Remain Airborne For 10 Months Straight.

“Scientists have long suspected that the common swift remains airborne for extraordinary amounts of time during its annual migration.

Now, a team of scientists in Sweden has proved that these birds fly for tremendously long periods of time. They affixed data loggers onto a total of 19 of the master fliers in 2013 and 2014, and recaptured the birds months or years later. Researchers found that the birds can spend almost their entire 10-month nonbreeding period on the wing.”