VANCOUVER -- During Metro Vancouver's cold snap, social media has been filled with photos of hungry hummingbirds and tips on how to keep hummingbird feeders from freezing.

But despite the attention from humans, the Wildlife Rescue Association of B.C. says it’s responded to an influx of calls about distressed and starving hummingbirds, and in two days alone this week took 75 calls and provided care for 10 birds.

"They eat other natural foods as well," said Linda Bakker, the co-executive director of Wildlife Rescue Association.

"But with the snow they really have a hard time finding food, and they have a super high metabolism. They need to eat constantly throughout the day, and sugar water gives them a lot of energy."

The Anna's hummingbird was voted Vancouver's city bird in 2017. The male sports a beautiful, sequin-like head of magenta feathers, and the bird is a favourite of backyard and patio gardeners.

Hummingbirds eat insects as well as flower nectar, and some hummingbirds migrate to warmer places in the winters.

But the proliferation of hummingbird feeders in urban areas and the mild climate of the South Coast means that many of the tiny birds stay in the Lower Mainland all winter long, Bakker said. The Wildlife Rescue Association is urging people to keep their humminbird feeders out during the winter, and make sure they don't freeze in cold weather.

Other local birds are adapted to winter weather in the Lower Mainland, and Bakker said the Wildlife Rescue Association doesn't recommend feeding other birds all winter long. But when it snows, all birds could use a little help.

"They're perfectly able to find their own food," she said. "But in the snow, you could put out some bird food or a bird feeder to help them through the snow dump."

Signs that birds may be in trouble include seeing birds on the ground that are unable to fly, birds that are weak and confused, are soiled, or have their tongue sticking out, according to the Wildlife Rescue Association.

Hummingbird feeders are filled with sugar water, and to prevent them from freezing in the cold weather, Wildlife Rescue suggests getting several feeders and rotating them throughout the day.

On social media, hummingbird enthusiasts have been sharing various tips for keeping feeders unfrozen, from using hand warmers to Christmas lights. Bakker said you can buy special hummingbird feeder warmers, but it's not necessary: many homegrown solutions will work just as well, provided they don't create a fire risk or make the liquid too hot.

Bakker said it's also important to change the sugar water and clean hummingbird feeders once a week with a bleach and water solution, and make sure they're completely dry before refilling the feeder to prevent mold.

Bakker said the Wildlife Rescue Association has been getting a lot of calls from people who are asking for advice, and between 10 and 25 per cent of those calls result in hummingbirds being brought in for care at the association's wildlife hospital.

Often that care involves simply warming up the birds and feeding them, but the association also treats hummingbirds for concussion if they've flown into a window.

If you notice a hummingbird that appears to be motionless in a tree early in the morning, it could be in its natural overnight state, when the quick-moving birds' metabolism slows down, they stop eating, and go into a "zombie-like" state called torpor.

Ian Young, a Vancouver-based journalist, described a bird he saw in this state on Twitter.

"An hour later, the sun now properly up, the bird seemed to have dropped from its perch," Young related. "But I looked closer, and there it was, alive and well and right way up, and fluffing its feathers on the same perch."

But Bakker said anyone who has questions about hummingbirds' welfare is welcome to call Wildlife Rescue's helpline at 604-526-7275.