Subfamily Sterninae is a group of birds that includes several different genera, such as Sternula, Gelochelidon, and Thalasseus. There are several synonyms that can be used to refer to this subfamily, such as the marsh terns, sea swallows, or marsh swallows. The common tern is one of the most well-known members of this group, with a distinctive black cap and elegant flight patterns. These birds are typically found near bodies of water, including rivers, lakes, and oceans. The Sterninae group includes many different species, each with their own unique characteristics and behaviors, making them a fascinating subject for birdwatchers and researchers alike.