Is the pelican the frigate bird's closest relative?

No, the pelican is not the frigate bird's closest relative. While both belong to the order Pelecaniformes, they are part of different families; pelicans belong to the family Pelecanidae, while frigate birds are in the family Fregatidae. Their evolutionary paths diverged significantly, making them more distantly related than one might assume based on their shared order. Instead, the closest relatives of frigate birds are other seabirds within their family, such as the tropicbirds.