So the only time I’ve spotted (what I believe to be) a magnificent frigatebird was down in South Padre Island, Texas years ago. You might notice, I’ve prefaced this with ‘I believe to be’ a magnificent frigatebird, since it could very well be a cormorant. I’m going with the the idea that it is either a magnificent frigatebird (too far away, and picture was taken from the side & hard to be able to tell sex) resting in the lagoon since it was still summertime and cormorants usually don’t show up until mid-fall to winter in the area.

The magnificent frigatebird is a large seabird that (in size) comes in somewhere between a brown pelican and American white pelican (larger than the brown, but smaller than the American white).
The exact color pattern for these birds depends on the sex of the bird. Breeding males are black, with their bright red throat pouch (which may or may not be visible). Females are basically black, with some white on their chests and bellies. The young will have dark feathers, but white heads and bellies along with a tan streak on their upper wings. The head feathers of the young will gradually transition from white to black as they age.
Since the picture I managed to get of the possible frigatebird is from the side–it is literally impossible to tell if it is a female or male.
These are sea birds that can be spotted along the coasts of certain states and throughout the Caribbean region.

The states, where you might see them foraging, possibly resting on piers or rocks, or possibly harassing other birds include: the Carolinas, Florida, Alabama, Mississippi, Georgia, Louisiana, Texas, and a little bit of southern California and southern Arizona (close to Baja California).
For spotting–look for the birds soaring over the waves using their tails to steer, or look for the birds that are ‘chasing’ others with hopes that they will give up their catches.
While they’re sea birds–their feathers aren’t ‘waterproof’ like other sea birds, so they actually don’t dive for their food. They will skim the surface of the ocean for food such as plankton, jellyfish, squids, and fish such as tuna, herring, and flying fish. They will also chase and harass other birds with the goal being to force the other birds to release or regurgitate their catches, which they will then dive for to collect before it hits the water.
Here were two other interesting facts about these birds:
Young frigatebirds learn to ‘chase and steal’ food from others by holding sticks in their beaks and chasing each other. When a stick is dropped, other young frigatebirds will dive to retrieve the stick and possibly ‘continue’ the game.
Incubation of the eggs take almost two months, the chicks don’t leave the nest until they’re almost six months old, and thier mothers will continue to feed them until they’re a year old.
My photography goals include: getting a better picture (so I can state without hesitation that the bird is a magnificent frigatebird), plus getting a picture of them soaring over the waves, and possibly harassing another bird for food.
Reference: https://www.allaboutbirds.org/guide/magnificent_frigatebird