A weak chum salmon run along B.C.'s coast is having a devastating effect on the local bald eagle population.

The fish is a staple in their diets and and the lack of it has the eagles starving and fighting for what little food is out there.

Animal rescue organizations are seeing more of the big birds in bad shape, said Bev Day, of the Orphaned Wildlife Rehabilitation Society, in Delta, B.C.

"We've had a few in that were hungry," Day told CBC News Thursday. "We got one in the other night that had been drowning. It got into the water and didn't have the strength to get out. Some people hauled it out."

There have been reports on Vancouver Island of eagles falling out of trees, dead from starvation.

The weak chum salmon run was made worse earlier this month by heavy rains that washed away many of the few remaining salmon carcasses.

Swarming dumps by the thousands

The birds have been forced to scavenge in garbage dumps, like the Vancouver landfill.

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A starving young bald eagle is given treatment by an animal technician in Delta, B.C. (CBC)

On biologist recently counted 1,400 eagles at the dump. Another 1,300 were counted at a landfill near Parksville, on Vancouver Island

The eagles are as attracted by the possibility of food as they are by the warmth generated by the rotting garbage, said Day.

"If they don't have enough body fat it's hard for them to produce enough of their [own] heat," she said.

The dump might seem to provide easy pickings, but wildlife officials said it can be a dangerous place. Poisoned pests, such as rats, are often disposed of in landfills, which in turn will poison an eagle.

There's also an impact on other species, like seagulls, who often have dumps to themselves.

The eagles should get a break in March when herring runs usually appear in the Strait of Georgia, biologists said.

With files from the CBC's Tim Weekes