(CNN) When researchers found a hummingbird with shiny gold feathers on its neck in Peru’s Cordillera Azul National Park, they thought it was a newly discovered species.
The park, part of an outer ridge of the eastern slopes of the Andes, is an isolated place – the perfect place to find a genetically distinct species.
“I looked at the bird and said to myself, ‘This thing is unlike anything else.’ My first thought was that it was a new species,” John Bates, a curator of birds at Chicago’s Field Museum, said in a statement.
After finishing the fieldwork in Peru and returning to the Field Museum to conduct a DNA analysis of the bird, the researchers made a surprising discovery.
The bird had never been documented before, but it was a hybrid as a result of two related hummingbird species: the Pink-throated Brilliant Hummingbird, Heliodoxa gularis, and the Rufous-webbed Brilliant Hummingbird, Heliodoxa branickii.
Both hummingbird species are known to have distinctive pink feathers on their necks, leading the researchers to question how pink mixed with pink could result in gold feathers.
“We thought it would be genetically distinct, but it matched Heliodoxa branickii in some markers, one of the pink-throated hummingbirds from the general range of Peru,” Bates said.
The first DNA analysis focused on mitochondrial DNA, which is passed down from the mother’s side, and it matched Heliodoxa branickii.
The researchers then looked at nuclear DNA, the result of genetic contributions from both parents of the bird, and revealed aspects of Heliodoxa branickii and Heliodoxa gularis.
However, the golden-throated hummingbird was not the result of an even genetic split. One of its ancestors was probably an even mix of the two species, while later generations appeared to have mated with branickii hummingbirds.
A study detailing the findings was published Wednesday in the journal Royal Society Open Science.
Since it is rare for hummingbirds of the same species to have such wildly different throat feathers, the researchers delved deeper into the mystery of the golden feathers on the hybrid species.
“It’s kind of like cooking: (I) if you mix salt and water, you kind of know what you’re going to get, but mixing two complex recipes together can produce more unpredictable results,” said study co-author Chad Eliason, Senior Field Museum researcher, in a statement. “This hybrid is a mixture of two complex recipes for a feather from the two parent species.”
The basic color of feathers comes from pigment, such as melanin, but feather cell structure and the way the light is reflected by the springs that create structural color. It is this structural color that results in the iridescent nature of hummingbird feathers.
The research team studied the bird’s neck feathers using an electron microscope to measure how light bouncing off the feathers created different colors.
“There’s more than one way to make magenta with iridescent,” Eliason said. “The parent species each have their own way of making magenta, which is, I think, why you can get this non-linear or surprising result when you mix the two recipes to produce a feather color.”
The discovery suggests that hybrids may contribute to the rainbow of colors displayed in different hummingbirds.
“Based on the rate of color evolution seen in hummingbirds, we calculated that it would take 6 (million to) 10 million years for this drastic rose-gold color shift to evolve in a single species,” Eliason said.
The researchers hope their work inspires others to keep an eye out for potential hybrid hummingbird species, Bates said.
“New tools such as genetic data are opening up new understandings of how these events occur across geography and time,” Bates said. “One question we want to look into in the region of Peru where this study was done is how this complex footland has evolved over time and what role these changes have played in the diversification of birds and other organisms.”