It's the busy season for wildlife rescuers, with the greatest number of injured or orphaned animals coming in during the summer months. But how do you stop baby birds from imprinting on their human caretakers before being released back into the wild?
One wildlife center in Longmont has a feathery solution.
Kelly Leonard was walking on the Colorado Trail at Copper Mountain after a late June snow when her dog spotted something on the ground.
"It was a little bird," Leonard said. "And he was totally immobile, he was shivering and his wing was out. He would not have made it through the night."
Leonard ran home and looked online for bird rehabilitators. She ended up contacting Greenwood Wildlife Rehabilitation Center, based in Longmont, and determined that the bird needed to be rescued. So she grabbed a box and a towel, scooped him off the trail, and drove down the mountain to the center when they opened the following Monday.
Summer is the height of bird season at Greenwood, according to Chelsea Barrett, the center's development manager. Last year, they treated over 1,800 birds with numbers peaking in June and July, and dwindling in September. The birds made up more than one-third of all the animals that come through their rehabilitation program.
A couple weeks after his arrival, the young crow found by Leonard is still in the bird nursery at Greenwood. Licensed wildlife rehabber Amanda Manoa prepares a meal of fruits, vegetables, kibble and seeds. Before stepping into the corvid room, Manoa pulls a black-feathered, beak-nosed Mardis Gras mask over her face. The reason?
"We really value things that can help us with the animals not habituating to people," Manoa said.
Research has shown that corvids, a family of birds that includes ravens, crows, magpies and jays, are extremely good at remembering faces. And if a baby bird imprints on a human feeding them, they might come up to humans for food later in life.
"That's not what we want," Manoa said. "We want them to have a very natural existence in the wild."
Manoa introduced the masks earlier this year, after reading the research — like University of Washington professor John Marzluff's study of crows and facial recognition — and hearing about similar programs at other wildlife facilities around the country.
"I went to the party store and bought some super cheap little masks with black feathers," she said. "I also wanted to change our face shape a little, so I looked for one that had a pointy nose instead of a flat thing."
The masks go on whenever something positive is happening, like feedings, changing bird baths or anything fun. When staff do something the birds perceive as negative, like administering subcutaneous fluids or West Nile vaccines, they don't wear the masks as a way to instill a little bit of fear of humans.
Kaeli Swift, a corvid researcher at the University of Washington, says birds like crows and ravens have a more unique relationship with humans than most other wildlife.
"These are animals that are inherently going to be more drawn to people," she said.
Swift says the ability of corvids to coexist with humans can be a good thing for the species evolutionarily, but at the same time, "if we overdo it, particularly with young birds … then you can cross a line to something that becomes a lot more mortally dangerous for them. And so I think it's really responsible that they are trying to disrupt an overconfidence-building by these birds with their human caretakers."
So why are corvids so smart, and how did they get so good at recognizing faces?
First, it's important to clear up a common misconception about facial recognition as an indicator of intelligence, said Swift. The more researchers study animal behavior, she said, the more it seems that the ability to recognize faces is actually not that special.
Lots of animals can tell faces apart and remember them — even bees, for example. But it's also true that corvids are very intelligent.
"Their brains have evolved to be kind of similar to ours in terms of their ability for complex thinking," Swift said.
There are a number of hypotheses as to why corvids evolved that way, from being social animals that rely on cognitive complexity to tell individuals in a group apart, to having generalized diets that require the ability to safely explore new environments and solve problems.
"So we don't know the answer explicitly yet, but it's a really cool area of study," Swift said.
Back at the Greenwood wildlife center, older magpies and crows are flapping around an outdoor enclosure. As Amanda Manoa walks toward them carrying a bundle of branches, the birds make warning noises, sounding very different from the young birds in the nursery begging for food.
"They're talking to each other but they're not begging at us, so that's a really good thing for us," Manoa said.
She puts on a mask again just before she brings the branches into each area of the enclosure for the birds to play on. The branches are a form of natural enrichment, something positive, so Manoa doesn't want the birds to associate them with a human.
The crows kept outside are over eight weeks old, and so far, their behavior is exactly what Manoa hopes to see.
"There's a little bit of a younger crow in there, and he was begging but he wasn't begging at me, he was actually begging at the older crow, so that's fine, that's good behavior for us," she said. "They know they're a crow, and that's what we really, really want."
The older birds will soon be moved to a larger enclosure to further develop their flight muscles. A couple weeks later, they'll be released back into the wild.
As for the little crow Kelly Leonard rescued on Copper Mountain, the staff at Greenwood plan to release him close to where he was found once he's ready.
Leonard said she wants him to be a happy, well-adjusted bird, and doesn't want him to be overly attached to humans. But part of her also hopes he remembers her.
"I just hope someday when my dog and I are out hiking on the Colorado Trail, I can look up and see him up there," she said.