While science has finally cracked the answer to El Paso’s mystery hummingbird’s maternal lineage, the answer sparks even more questions. 

First spotted in the Franklin Mountains in January, the little bird stumped scientists and birders alike. Experts guessed the unique bird was most likely a hybrid — the combination of two species — but there was a longshot possibility of it being a Central American White-bellied Emerald. 

After months of testing, it was determined that the shimmering blue and green bird is a hybrid – and its mother was a Costa’s hummingbird, a species most often found in Western Mexico, the southern tip of California and into Arizona.

Michael Harvey, an assistant professor in biology at the University of Texas at El Paso, along with some colleagues, netted the bird in February, and took two tail feathers, hoping for a skin or blood sample to extract a good genetic sample from. After taking some measurements, they released the bird, which has not been spotted since. 

“Although many thought the bird might be a hybrid, I don’t remember anyone suggesting Costa’s as a potential parent. Pretty wild,” Harvey wrote in a November email to researchers and bird enthusiasts. 

Hybridization is well-known within hummingbirds and can occur in them even in species that are not closely related, said Chris Witt, a professor of biology and the curator of birds at the Museum of Southwestern Biology at the University of New Mexico.

“What’s really cool about this particular bird is its phenotype, or expressed traits, are transgressive, outside of the ranged traits of its parents,” Witt said. 

“They have a good chance of finding out who the father is,” Witt said. “But that’s going to take some careful lab work.”

Andrea Sarinaña, a senior in biology in her second semester in Harvey’s lab, only had a few chances to get any genetic material to sample. 

“I only had two feathers, and there was no backup,” Sarinaña said. “If the two feathers failed, then the project would essentially come to a stop.”

There was no tissue at the base of the feather, so all hope lay within the shaft and the small blood vessels holding any genetic material. The genetic material is split between traits inherited from a mother — called mitochondrial DNA — and material inherited from both parents — nuclear DNA. 

Sarinaña tried amplifying the genetic codes, and out of 12 tests, only the first one was successful. After sequencing the code and comparing it to an open-source database on the National Institutes of Health website, they found a 100% match to Costa’s hummingbird. 

“The fact that it was a Costa’s hummingbird surprised everyone,” she said. “None of us were expecting it, because it’s not native to El Paso.”

Sarinaña will try to amplify nuclear genes to reveal the father – and even the sex of the hybrid bird. Harvey said if the amplification fails, the team might try to sequence smaller samples to piece together the whole genome. Either way, it’s likely to be months before results come in. 

Sarinaña said the project has fueled her interest in answering unknowns through science. 

“I feel like pursuing a degree in genetics, or a Ph.D. in genetics is gonna let me continue learning throughout the rest of my life and continue to make a difference,” she said.