Territories: a fixed space defended by an individual or group of individuals -- can be short or long period of time (e.g., hummingbird at feeder, year-round resident -- territory holder is dominant in this space over all other members of the species -- can be just for feeding, roosting, breeding, or all-purpose -- size varies with diet and resource needs of the species

Territories can be very small and just for breeding

Some territories can be all inclusive, held year-round, to provide food, shelter, nesting space Carolina Wren

Margaret Nice (1941) published classic paper on territory types in birds based on systematic surveys: Type A: all purpose, used for mating, nesting, feeding, shelter, etc. 75% of Passeriformes Type B: mating and nesting only, food obtained elsewhere in neutral areas or separate feeding territories may exist; many colonial species Type C: mating only, includes grouse leks with nest built by female elsewhere Type D: nesting only, usually small nest area as in swallows. Common when nesting habitat is limited or patchy Type E: feeding only, defended separately from nesting territory; hummingbirds at feeder, gulls at trash cans Type F: roosting only, rarer but defend best spot for energy conservation, perch. Starlings, anhingas 1883 – papers on birds

Townsend’s Solitaire and ‘super territories’ -- defends much larger area than needed for food (juniper berries) in winter (Type E), up to 600x larger -- thought to provide insurance against sudden loss of winter food -- has Type A territory in summer

Western Gulls and Territory Size -- size depends on microhabitat types -- open areas need more space for chicks to hide, more aggression with neighbors -- rocky areas can be smaller, more aggression with potential interlopers

-- driving forces for this behavior include patchy and limited nesting sites, patchy food supplies, protection from predation, or combination of all factors Colonial Breeding -- Information Center Hypothesis: individuals watch and learn from others in the colony, follow to food supplies that may be ephemeral -- e.g., gulls, cliff swallows

westernviews.us Cliff Swallows feed at insect swarms Observations have shown that clusters of birds (within 10 nests of each other) will depart at same time Behavior persists only if different birds find food

Disadvantages of Colonies -- disease spread more easily (e.g., botulism, avian cholera) -- parasites spread more easily (e.g., ticks, lice) -- intraspecific competition intensified, e.g., Ashmole’s halo in seabird colonies swallow bug effect of parasites on chick growth animal.discovery.com

Foraging by Imperial Cormorants shows halo effect Birds also forage to minimize energy expense and maximize energy gain (optimal foraging) Wilson et al. 2011

Intraspecific competition at colonies also means constantly maintaining the territory, may necessitate winter attendance e.g., murres, auklets, gulls on Farallon Islands floaters – non-breeders searching for nest sites, difficult to know numbers, but removal of breeders indicates their presence (penguins)

Latrabjarg Bird Cliffs, Iceland