are shorebirds and pelagic birds part of "marine biology"?

sorry if this is a dumb question !! I was just wondering if pelagic birds (or otherwise migratory birds that travel over water frequently and eat from marine environments) and shorebirds are considered part of marine biology or if they are more the focus of terrestrial biologists? I know everything is interconnected which is an amazing thing about our Earth, but in which field would you say these organisms are most represented? thank you!! :)