Frigate bird and Pelecaniform seabird

Frigate bird noun - Long-billed warm-water seabird with wide wingspan and forked tail.

Pelecaniform seabird and frigate bird are semantically related. In some cases you can use "Pelecaniform seabird" instead a noun phrase "Frigate bird".

Pelecaniform seabird noun - Large fish-eating seabird with four-toed webbed feet.

Frigate bird and pelecaniform seabird are semantically related. Sometimes you can replace phrase "Frigate bird" with "Pelecaniform seabird", this phrases are similar.