Territory: a defended area.

• territory vs.home range: home range is area within which a bird spends most of its time, over a specified period
• resources provided by territories: mating opportunities (especially for males); floaters, males without territories, may not mate. Food for adults, young; protection against predators; sites...

• Type A - all purpose breeding (breeding, feeding of adults; food for young.) ex: many passerines, raptors, a variety of species
• Type B - nesting; some feeding of nestlings; adults feed elsewhere. ex: red-winged blackbirds
• Type C - nest only. ex: many gulls, auks
• Type D - mating only. ex: lek species such as many grouse, manakins, etc.
• polyterritoriality: male holds more than one, non-consecutive territory. ex: Pied Flycatcher (a European species in the thrush and relatives group)
• non-breeding territories: birds of either sex may hold territories in the winter.  May defend against individuals of either sex.
• non-territorial species: many species are not observed to defend areas.  Ex: many finches (Fringillidae)

• usually by males against conspecific males; displays, songs, fights...
• female defense of territories
• monogamous species: females may defend joint territory against females
• polygynous species: females may defend a smaller territory within the male territory
• interspecific territoriality: rare
• may occur "by mistake" if species can not recognize each other
• may occur between competitors: red-winged blackbirds and yellow-headed blackbirds where the species occur together