Many people may equate songbirds more with Snow White than endurance flying, but Dutch scientists recently observed one species flying for 40 to 60 hours nonstop over the Sahara desert while migrating, Phys.org reports. More than 2 billion songbirds are estimated to cross the world’s largest hot desert annually, but scientists have until now had trouble tracking the birds’ journeys because of their small size and high numbers. The researchers attached small electronic loggers to 80 pied flycatchers to measure light and temperature readings along their migration routes. Once 15 of the birds were recaptured, the scientists could then extrapolate from the data to estimate latitude and longitude and when the birds took to caves to rest, according to their study in the journal Biology Letters. Two uninterrupted periods of flying for 40 to 60 hours were observed, and the songbirds were apparently able to keep flying during the hottest parts of the day.