A new study suggests there’s nothing soft about pink, as it was revealed that the pinkest flamingos are the toughest. Published in the journal Ethology, the study from the University of Exeter and WWT Slimbridge Wetland Centre, both in the UK, found that a pink flush of feathers was a good indicator of how aggressive a bird was likely to be when feeding, as well as a sign of good health or that the bird was ready to breed.
For the study, researchers observed the behavior of Slimbridge's captive lesser flamingos in different feeding situations ranging from small indoor spaces to large outdoor spaces, with or without a pool. They found the flamingos with lots of space by the outdoor pool spent twice as much time foraging and half as much time displaying aggressive behaviors compared to birds who were indoors competing to feed from a bowl. Interestingly, their observations also revealed that when the race for food turned sour, the birds most likely to resort to fisticuffs were the pinkest flamingos, irrespective of whether they were male or female.

The findings form a strong argument for ensuring captive birds are fed over a wide space where possible, as cramped conditions are more likely to result in fights. Flamingos live in large groups with complex social structures (they even have cliques), and the research indicates that small changes to how zoos and sanctuaries feed their flamingos can keep them content and colorful.
"Colour plays an important role in this, said Dr Paul Rose, from the University of Exeter, in a statement. “The colour comes from carotenoids in their food, which for lesser flamingos is mostly algae that they filter from the water.
"A healthy flamingo that is an efficient feeder – demonstrated by its colourful feathers – will have more time and energy to be aggressive and dominant when feeding. When birds have to crowd together to get their food, they squabble more and therefore spend less time feeding.”
Lesser flamingos don’t have a breeding season and instead simply breed when they’re fit enough to do so. This health is indicated by the color of their feathers, which are pinker in their prime and paler when they’re poorly. The indication that a bird is ready to reproduce is described as a “pink flush” in their plumage, which goes away when the bird parents a chick or is past its reproductive prime.
"This study is a great example of why I love working with WWT Slimbridge,” said Dr Rose. "Based on my observations, I suggested some changes – and the keepers were willing to try them out. As a result, we get pinker, more relaxed flamingos."