January 27, 2022
Winter leaves hummingbirds in the cold: dead, alive … or in torpor?
Chris O'Neill

A feeder suspended from a hanging indoor light fixture helped revive an Anna’s hummingbird found motionless outside on a cold winter day. The species’ winter range has shifted north over the past several decades, making it more common for wildlife rescue centers to be contacted about hummingbirds found grounded in the cold. (Photo courtesy Ted Stannard)

January 27, 2022
Winter leaves hummingbirds in the cold: dead, alive … or in torpor?
Chris O'Neill

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On a frozen morning this past December, Bellingham resident Ted Stannard found a tiny bird lying motionless below his backyard feeders — an Anna’s hummingbird.

He gently placed the bird on a soft cloth in a small box and brought the hummingbird inside, hoping the warmth might resuscitate it. He placed the box in a quiet part of his home and waited to see if the bird would respond. 

“We had him around the corner in the little breakfast nook,” Stannard said. “You could tell he was breathing but [its breathing] was very low.”

The Anna’s hummingbird is the only hummingbird adapted to winter as far north as southwest British Columbia. It has bronze-green feathers and a gray belly; male Anna’s sport a reddish-colored hood and the female has red only on her neck.

The tiny dynamos weigh between one- and two-tenths of an ounce — roughly the weight of a standard sheet of laser printer paper. With a resting heart rate between 420 to 460 beats per minute and an average body temperature of 107, the Anna’s have a very high metabolism requiring constant food. Cold snaps like the ones in recent months can easily prove fatal for these birds.

“He was thoroughly conked out and I let him sleep,” Stannard said. “I thought maybe he would wake up and just sit there.”

Hours later, the hummingbird regained its senses, and Stannard was shocked by how quickly the bird became mobile.

“All of a sudden he was flying around the house,” Stannard said. “Then I thought, well, maybe we can feed him indoors.”

Stannard hung one of his feeders from a pendant lamp over his dining-room table and the bird began to feed but quickly grew restless.

“He was anxiously heading for every bright spot on the ceiling,” Stannard said. “It became clear he wanted out.”

Stannard dimmed the lights except for one hallway leading to the door. “When he got in there, I opened the door and he zoomed out,” Stannard said. 

Climate change and torpor

According to the Seattle Audubon Society, the Anna’s hummingbird range has shifted over the years from wintering in western California to lower British Columbia because of warmer temperatures due to climate change and more food in backyard feeders and garden flowers. 

Another reason for the Anna’s success is a survival mechanism shared by birds, according to Shona Aitken, education coordinator at Wolf Hollow Wildlife Rehabilitation Center on San Juan Island. 

 “They’re pretty tough and they can deal with cold weather by going into torpor,” Aitken said. “Their metabolic rate goes down and their temperature goes down and that can help them conserve energy.” 

Going into torpor allows the Anna’s to reduce their body temperature from 107 to as low as 48, while their heart rate can dramatically drop from over 400 beats per minute at rest to around 50 beats. Aitken said that in most cases when someone finds an Anna’s motionless, the bird is in a state of torpor. 

“This torpor thing is normal when it’s colder,” Aitken advised. If a feeder is in a sheltered, warm area, the birds may just be resting in between feedings. Only intervene if a bird is visibly injured or found lying on the ground to protect them from cats and other predators. 

Call the pros, please

Suzanne West, executive director at Sarvey Wildlife Care Center in Arlington, said that it is commonplace to see Anna’s hummingbirds at her center during the winter months.

“We’ve had nine hummingbirds in the last six weeks,” said West. “Five of those were released, one was euthanized and three passed away within the first 24 hours.”

West advised concerned citizens to call their local wildlife rehabilitators as soon as they find an animal in need of assistance. Many well-intentioned but inexperienced people do more harm if not properly directed by a professional. One of the most common mistakes people make with hummingbirds, West said, was to attempt to feed them with a syringe and spill nectar on their feathers.

“These birds were coming in sticky,” West said. “Take a small feeder and put it in the box so they can self-feed; don’t offer food or water to an animal unless you’ve been directed to do so by a wildlife rehabilitator.”

West advised creating a quiet and warm cave-like environment with a box lined with a soft cloth or tissue paper. Cover the box with a towel to keep the bird as unaware of its surroundings as possible.

“They don’t know you’re not the cat or hawk or some other predator that’s trying to kill them,” West said. “That can cause them to die — just the stress.” 

As for Stannard’s revived hummingbird, he wasn’t sure if he made it or not, but a recent sighting gave him hope.

“There were two a couple afternoons ago,” Stannard said. “I don’t know if it’s the same hummingbird, but they’re back.”

Reported by Chris O’Neill

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