Flamingos are famous for their long legs and necks and their pink plumage. And for the first time, it has been discovered that birds make loyal lifelong friendships and that physical traits may be involved in those bonds.
Long-lived relationships among flamingos include couples who have mated, build nests together, and raise chicks each year, as well as same-sex friends and groups of three to six close friends.
There are six species of flamingos that inhabit large saline or alkaline lakes, tidal flats, or shallow coastal lagoons in the Americas, Africa, Europe, and Asia. Flocks of these gregarious birds usually number in the thousands.
Paul Rose, study leader and behavioral ecologist at the University of Exeter in the UK, wanted to find out whether flamingos create complex bonds within their large groups.
Between 2012 and 2016, Rose collected data on four captive flocks of common, Chilean and dwarf flamingos and the great parinas that live at the Wildfowl & Wetlands Slimbridge Wetland Center in Gloucestershire. The flocks, ranging in size from just 20 individuals to more than 140, were considered similar in structure and behavior to wild groups.
After collecting this data over five years, Rose observed that flamingos maintain stable friendships, characterized mainly by being close to each other. These links may last for decades; flamingos can live 50 years.
"The fact that they are so long-lived suggests that these relationships are important for their survival in the wild," he says.
Rose determined that these wading birds avoid certain individuals, just like humans, another highly social species. Says avoiding might prevent disputes: "One way to reduce stress and fighting is to avoid birds you don't get along with."
Understanding the social ties of birds could help conservationists better manage both captive and wild flamingo populations. Rose points out the populations of four species of flamingos are declining.
Avian friends
For this research, Rose photographed the downtown flocks daily at four preset hours in spring and summer and three times in fall and winter. He also photographed the birds that were placed together in different subgroups in each flock. The birds have rings on their legs, which makes it easy to identify each individual.
A flamingo colony is a crowded mass of birds that eat, groom and sometimes fight. If one bird gets too close to another, they use their long necks and huge beaks to attack each other and sometimes go to great lengths to show that one has a longer neck than the other.
Consequently, Rose defined neck length as a measure of friendship between flamingos: birds that are sitting or standing "less than a neck away from another bird" were considered friends. When other flamingos were nearby, but more than a neck apart, Rose marked them as belonging to different groups.
He found that larger flocks had more variety and more social interactions with complex social networks consisting of subgroups of two, three, or six birds.
Some birds were so consistently friends over the five years of the study that Rose said she could easily predict which ones would be together.
"There were two close-knit older females who did everything together, from courtship displays to nest building, and they were always joined by a male 20 years younger," says Rose. Their study appears in the June issue of the journal Behavioral Processes .
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