Flamingos form strong pair bonds although in larger colonies flamingos sometimes change mates, presumably because there are more mates to choose from.  Flamingo pairs establish and defend nesting territories. They locate a suitable spot on the mudflat to build a nest (the spot is usually chosen by the female).  It is during nest building that copulation usually occurs. Nest building is sometimes interrupted by another flamingo pair trying to commandeer the nesting site for their own use. Flamingos aggressively defend their nesting sites. Both the male and the female contribute to building the nest, and to defending the nest and egg.  Occasional same-sex pairs have been reported.