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. 
The tobacco industry produces a lot of cigarettes, and that leads to a lot of filters discarded on the ground. According to Americans for Nonsmokers’ Rights, we end up with billion pounds of them each year, making cigarette butts the most common type of litter. Plenty of creative solutions, from musical ash trays to roads made from cigarette waste, have been proposed in the past. Now, a new startup is developing a strategy that takes advantage of something that’s already a part of our cities. As The Next Web reports, Crowded Cities wants to train urban crow populations to pick up our cigarette butts.