At least two juveniles
Along with some sanderlings (Calidris alba) and common terns (Sterna hirundo).
They are black kites as they were a large brown bird of prey with a forked tail. The tail fork can be assumed from the bird with the splayed tail as the feathers on the outer edge are longer than those in the middle of its tail. They were also in a group and black kites are very social. They are very abundant in the area.
A group of black kites were feeding together on a piece of roadkill which is a common sight along the highway. Sometimes they are joined by ravens. The kites would all fly off when a car approached but would quickly return to their meal.