Well... you asked.
V
Synonyms: flock1, herd, drove2, pack1, gang1, brood
These nouns denote a number of animals, birds, or fish considered collectively, and some have human connotations. Flock is applied to a congregation of animals of one kind, especially sheep or goats herded by people, and to any congregation of wild or domesticated birds, especially when on the ground. It is also applicable to people who form the membership of a church or to people under someone's care or supervision. Herd is used of a number of animals, especially cattle, herded by people; or of wild animals such as antelope, elephants, and zebras; or of whales and seals. Applied to people, it is used disparagingly of a crowd or of the masses and suggests the gregarious aspect of crowd psychology. Drove is used of a herd or flock, as of cattle or geese, that is being moved or driven from one place to another; less often it refers to a crowd of people in movement. Pack is applicable to any body of animals, especially wolves, or of birds, especially grouse, and to a body of hounds trained to hunt as a unit. It also refers disparagingly to a band or group of persons. Gang refers to a herd, especially of buffalo or elk; to a pack of wolves or wild dogs; or to various associations of persons, especially when engaged in violent or criminal pursuits. Brood is applicable to offspring that are still under the care of a mother, especially the offspring of domestic or game birds or, less formally, of people.·The following related terms are used as indicated: bevy, a company of roe deer, larks, or quail; cast, the number of hawks or falcons cast off at one time, usually a pair; cete, a company of badgers; covert, a flock of coots; covey, a family of grouse, partridges, or other game birds; drift, a drove or herd, especially of hogs; exaltation, a flight of larks; fall, a family of woodcock in flight; flight, a flock of birds in flight; gaggle, a flock of geese; gam, a school of whales, or a social congregation of whalers, especially at sea; kennel, a number of hounds or dogs housed in one place or under the same ownership; kindle, a brood or litter, especially of kittens; litter, the total number of offspring produced at a single birth by a multiparous mammal; murder, a flock of crows; muster, a flock of peacocks; nide, a brood of pheasants; pod, a small herd of seals or whales; pride, a company of lions; rout, a company of people or animals in movement, especially knights or wolves; school, a congregation of fish, or aquatic mammals such as dolphins or porpoises; shrewdness, a company of apes; skein, a flight of wildfowl, especially geese; skulk, a congregation of vermin, especially foxes, or of thieves; sloth, a company of bears; sord, a flight of mallards; sounder, a herd of wild boar; stable, a number of horses housed in one place or under the same ownership; swarm, a colony of insects, such as ants, bees, or wasps, especially when migrating to a new nest or hive; troop, a number of animals, birds, or people, especially when on the move; warren, the inhabitants, such as rabbits, of a warren; watch, a flock of nightingales; and wisp, a flock of birds, especially of snipe.
FURTHER...
PATTERNS OF FLOCK SIZE, DIET, AND VIGILANCE OF NATURALIZED MONK PARAKEETS IN HYDE PARK, CHICAGO
Abstract
We examined patterns of diet, foraging group size, and vigilance effort of naturalized Monk Parakeets (Myiopsitta monachus) in Hyde Park, a neighborhood of Chicago, Illinois. Parakeets exhibited a highly seasonal and varied diet consisting of fruits, seeds, and buds, and they fed almost exclusively on birdseed provided at backyard feeding stations during the winter months. Birds foraged in groups of 1 to 31 birds, but most flocks were of 10 birds or less. Foraging group size was greatest in the fall and early winter, and smallest at the beginning of the spring when breeding began. Monk Parakeets adjusted their vigilance effort with changes in flock size. Individual vigilance effort declined with increasing flock size through a decrease in time spent scanning as well as the number of times scans were initiated. The number of parakeets exhibiting vigilance in a flock at any given time also decreased with flock size. It is likely that the highly adaptable and varied diet of Monk Parakeets contributes greatly to the persistence and growth of populations in a variety of North American habitats.
PATTERNS OF FLOCK SIZE
Flock size was highly variable (range = 1–31), but in general parakeets formed relatively small feeding groups, usually of five birds or fewer (4.8 ± 0.3, median = 4). Of the 300 flocks observed, 81 (27.0%) contained more than 5 birds, but only 29 (9.7%) were larger than 10 birds. The largest group seen consisted of 31 birds feeding on carpetweed (Mollugo sp.) seeds in October 1998. The largest mean flock sizes were recorded for October through January (Fig. 3), with a significant decrease in the number of birds feeding together in late winter (χ210 = 30.5, P < 0.01). By February, smaller flocks were seen, usually consisting of one or two pairs of birds. The mean flock size of 3.0 ± 0.4 calculated for May was the lowest of any month. This time of year coincided with the period when parakeets were most actively attending to their nests. In July and August, several of the observed flocks appeared to consist of a pair of birds accompanied by one to three juveniles begging for food.
The number of flocks seen per hour of observer effort each month was relatively constant, whereas the number of birds seen per hour decreased from October to May, approximately coinciding with the pattern for average monthly flock size (Fig. 3).
DISCUSSION
Monk Parakeets are gregarious and often form large flocks when feeding. It is likely that seasonal changes in flock size are due to a number of factors. Gilardi and Munn (1998) found that Neotropical parrots dwelling in dense, humid forests exhibited relatively small flock sizes in the nonbreeding season, supporting the aridity hypothesis proffered by Cannon (1984). Monk Parakeets inhabit open and moderately dry habitat in Chicago and exhibit larger flock sizes in autumn and winter, when food resources are assumed to be less abundant. A seasonal change in foraging group size, as documented here, also has been noted for naturalized Mitred Parakeets (Aratinga mitrata) inhabiting arid, open areas in southern California (Collins and Kares 1997), and for mixed-species flocks of Neotropical parrots in Costa Rica (Chapman et al. 1989).
Formation of larger flocks when resources are scarce or widely dispersed may be important to survivorship in Monk Parakeets, especially juveniles during their first autumn and winter. Individuals in flocks would presumably learn the location of food sources more rapidly than they would if they foraged alone (Cannon 1984). However, competition and the limited amount of most food items eventually constrain flock sizes (Pulliam and Caraco 1984). We observed intense competition between Monk Parakeets in flocks for perches at backyard feeding stations during the winter. The high nutritional value of foods eaten at certain times during the year, such as birdseed rich in oils, also may limit the individual benefit of larger flock sizes (Pulliam and Caraco 1984).
The risk of predation also may significantly influence the flock size of foraging Monk Parakeets. Westcott and Cockburn (1988) hypothesized that Australian parrots join flocks to minimize risk of predation, and that resource utilization has only minor influence. Monk Parakeets spend a significant amount of time scanning for potential predators while foraging. Our results indicate that individuals can significantly decrease their vigilance effort by joining a flock and thus devote more time to other activities, especially foraging. When more eyes are available to scan and detect predators, the likelihood of escape is increased (Pulliam and Caraco 1984). Charnov and Krebs (1975) suggested that this benefit is even greater for species that sound an alarm call when a predator is detected. Monk Parakeets are known to sound their alarm call in response to potential predators (Martella and Bucher 1990), and we also observed this behavior on several occasions during this study. Flocking by parakeets results in a reduction of an individual's vigilance effort, but it is unknown whether the risk of predation influences flock size more than resource availability. Spreyer and Bucher (1998) reported that Monk Parakeets at foraging areas in Argentina exhibit behaviors suggestive of a sentinel system, but we did not observe such behavior in our study.
Flocking by parrots while feeding is likely due to a complex set of ecological factors (Pulliam and Caraco 1984). Our results suggest that predator avoidance and exploitation of heterogeneous food resources both may influence size of foraging groups in Monk Parakeets in Chicago. These results invite further studies on the ecological factors influencing flock size in parrots. Future studies of Monk Parakeets might examine the role that communal roosting plays in the daily movements of individuals and flocks (Chapman et al. 1989, Mabb 1997). Radio telemetry studies of home range and foraging in Monk Parakeets also are needed.
