Editing Rhea (bird) (section)

==Behavior==
[[File:Greater rhea skeleton.jpg|right|thumb|Rhea skeleton]]

===Individual and flocking===
Rheas tend to be silent birds, except when they are chicks or the male seeks a mate. During the breeding season, the male will attempt to attract females by calling. This call is a loud booming noise. While calling like this, they will lift the front of their body and ruffle their plumage, all while keeping their neck stiff. They will then extend and raise their wings and run short distances, alternating with their wings. He may then single out a female and walk alongside or in front of her with a lowered head and spread wings. If the female notices him, he will wave his neck back and forth in a figure eight. Finally, a female may offer herself, and copulation will commence.<ref name="Davies"/>

During the non-breeding season they may form flocks of between 20 and 25 birds,<ref name=Coomber>{{cite book|last=Coomber|first=Richard|title=Birds of the World|year=1991|publisher=Colour Library Books Ltd.|location=Godalming, Surrey|isbn=0862838061|pages=[https://archive.org/details/photographicency0000coom/page/8 8–9]|editor=Gill Waugh|chapter=Rheiformes: Rheas|chapter-url=https://archive.org/details/photographicency0000coom/page/8}}</ref> although the lesser rhea forms smaller flocks than this. When in danger, they flee in a [[zigzag]] course, using one wing and the other, similar to a rudder. During the breeding season, the flocks break up.<ref name="Davies"/>

===Diet===
Mostly, rheas are herbivorous and prefer broad-leafed plants, but they also eat fruits, seeds, roots, and insects such as grasshoppers, small reptiles, and rodents.<ref name=Davies/> Young rheas eat only insects for the first few days. Outside the breeding season, they gather in flocks and feed with deer and cattle.<ref name=Coomber/>

===Reproduction===
Rheas are polygynandrous, with males courting between two and twelve females and females commonly mating with multiple dominant males during the breeding season. After mating, the male builds a nest where each female lays eggs. The nest is a simple scrape in the ground, lined with grass and leaves.<ref name=EoB/> The male incubates from ten to sixty eggs. The male will use a decoy system and place some eggs outside the nest, then sacrifice these to predators so they do not attempt to get inside the nest. The male may use another subordinate male to incubate his eggs while he finds another group of females to start a second nest with.<ref name="Davies"/> The chicks hatch within 36 hours of each other. Right before hatching, the chicks begin to whistle.<ref>{{Cite web|date=2020-01-27|title=Listen: Greater Rhea Nests Are Filled With Dozens of Whistling Eggs|url=https://www.audubon.org/news/listen-greater-rhea-nests-are-filled-dozens-whistling-eggs|access-date=2022-01-26|website=Audubon|language=en}}</ref> The group of females, meanwhile, may move on and mate with other males. While caring for the young, the males will charge at any perceived threat approaching the chicks, including female rheas and humans. The young reach full adult size in about six months but do not breed until they reach two years of age.<ref name="EoB"/>