One study on how they do it.
https://publish.wm.edu/cgi/viewconte...ontext=reports
Spent hour upon hour watching these birds from the ships helideck, failing that, going to the bow and passing the time watching dolphins. Never ever observed the birds attempt to get airborne on no wind days, they'd just paddle out of your way. Only times ever saw them above sea level was heading offshore (flying) and a bird was soaring along in a dry front at 1,500 feet (Golden Beach
JT), the other was popping out of a cloud at 500 feet to be confronted by a bird. I assume he was soaring in some localised disturbance that wasn't obvious to us.