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Listen to part of a lecture in a biology class. The professor is discussing the behavior of a particular species of bird, the European starling. Professor: Now, we've talked about how some birds migrate in large flocks. But the European starling has a rather unique social behavior. Unlike many birds that form flocks only during migration, starlings gather in enormous groups, sometimes numbering in the hundreds of thousands, to roost together at night. These gatherings are called communal roosts. The interesting thing is that they don't just happen randomly. Researchers have found that starlings choose roost sites that are near abundant food sources. This might seem counterintuitive, because with so many birds, competition for food would be fierce. However, the roost acts as an information center. Birds that have found good feeding areas return to the roost, and the next morning, less successful foragers follow them to those areas. This way, the whole group benefits. Additionally, the sheer number of birds provides protection from predators, since it's harder for a predator to target an individual in a massive swirling cloud of birds. So, the communal roost is not just a sleeping arrangement; it's a complex social structure that enhances survival.