The sight of birds moving together in the sky is a common natural spectacle. English contains a rich vocabulary of collective nouns, often known as terms of venery, to describe specific avian assemblies. These specialized names originated centuries ago, reflecting the perceived characteristics or behaviors of the birds they describe. Understanding these terms helps explore the natural history and physics of why birds fly together.
The Universal Answer: What is a Flock?
The most widespread and generally accepted term for a group of birds is a “flock.” This generic term applies universally to nearly all bird species when they gather, especially in flight or while foraging. This includes groups of pigeons wheeling over a city square or dozens of mixed species feeding together in a forest.
The term “flock” is particularly useful when the specific species is unknown or when the group is composed of multiple different species. Other simple, non-specific synonyms include “assembly” or “congregation.” These terms acknowledge the social nature of the birds without requiring specialized knowledge.
Beyond the Flock: Specific Collective Nouns
Many bird species possess unique collective nouns that are more descriptive than the general term “flock.” These specialized names often highlight a distinctive behavior, sound, or characteristic of the species when gathered. A “murmuration” is the most famous, referring specifically to a large group of European starlings performing coordinated aerial acrobatics before roosting. The name derives from the low, indistinct sound created by the thousands of beating wings within the dense cloud of birds.
The term “kettle” describes a group of soaring raptors, such as hawks or vultures. This name is inspired by the visual effect of the birds circling tightly within a thermal updraft, resembling ingredients stirring in a pot. Broad-winged hawks form immense kettles, using these columns of warm, rising air to gain altitude with minimal energy expenditure before gliding onward.
For geese, the collective noun often changes depending on their activity and formation in the air. When flying, these groups are most precisely called a “skein” or a “wedge,” with “skein” referring to the elongated formation itself. The V-formation is an aerodynamic strategy that allows trailing birds to exploit the upwash of air created by the wingtip vortices of the bird ahead. This significantly conserves energy for the group.
A group of owls is traditionally known as a “parliament.” This term stems from the association of owls with wisdom, rather than their group behavior, as owls are generally solitary. A group of finches is most commonly referred to as a “charm,” capturing the delightful nature of these small, lively songbirds. Sparrows, known for their gregarious nature, are often called a “host” or sometimes a “quarrel.”
The Functional Reasons for Group Flight
Birds fly in groups primarily for survival and efficiency. One of the most significant advantages of grouping is predator evasion, achieved through two related phenomena: the dilution effect and the confusion effect. The dilution effect reduces the probability of any single individual being targeted by a predator as the group size increases.
The confusion effect arises when a predator is unable to focus on and successfully track a single target within a large, rapidly moving mass of birds. The sudden, synchronized movements of a starling murmuration make it harder for a falcon to lock onto a specific bird. Furthermore, a larger group offers better collective vigilance, as more eyes are available to detect threats earlier, allowing the flock to react sooner.
Group flight also provides substantial benefits in terms of energy conservation. By positioning themselves precisely within the upward-moving air created by the preceding bird’s wingtip vortices, birds can reduce drag and increase lift. Studies on great white pelicans flying in formation have shown a reduction in wingbeat frequency and heart rate compared to solo flight, indicating a measurable energy saving.
Finally, gathering together facilitates the efficient transfer of information. Social birds often rely on the movements and vocalizations of their flockmates to locate newly discovered patches of food. This collective knowledge-sharing allows the entire group to forage more effectively and reduces the individual time spent searching for sustenance.