Canada Goose’s jackets aren’t flying out of department stores the way they used to — and their prices are heading south for Christmas.

The Toronto-based outerwear maker — which got a boost in 2013 when supermodel Kate Upton appeared on the cover of Sports Illustrated wearing little except one of the bulky, badge-encrusted coats — typically sells its jackets for $900 and up.

But this holiday season, a Wall Street analyst calculates the jackets are getting marked down 13 percent on average — nearly twice as steep as last year’s 7 percent — with retail experts blaming everything from slow traffic at shopping malls to internet campaigns from animal-rights activists.

“Some of the markdowns are deeper and some shallower,” said John Morris, an analyst at DA Davidson who published a holiday pricing study this week. But overall, “there are deeper markdowns this year, which undercuts the brand equity and integrity.”

Canada Goose is one of the two most heavily discounted brands out of 18 clothing companies that Morris covers, including Lululemon Athletica, Urban Outfitters, L Brands and Columbia Sportswear. The other laggard is battered teen label Abercrombie & Fitch.

In past seasons, shoppers rarely found a Canada Goose jacket for less than its full sticker price — despite the fact that those prices frequently topped $1,000 at venues like Neiman Marcus, Saks Fifth Avenue and Bergdorf Goodman.

“It has always had strong pricing power in department stores,” Morris said. “But that’s eroded… It doesn’t seem to have as prominent a place under the Christmas Tree this year.”

Canada Goose denied the report’s claims, saying they have been “proven false” through web searches of retailers like Nordstrom and Neiman Marcus, where the coats were still selling for full price this week.

“Canada Goose is not a promotional brand. We maintain consistent pricing through our country-specific distribution channels,” the company told The Post.

Nevertheless, upscale mall anchors like Saks, Nordstrom and Bloomingdale’s have more Canada Goose inventory than they can sell, according to Craig Johnson of Customer Growth Partners, a retail research firm.

“A lot of stores still have plenty of Canada Goose outerwear in all sizes and colors,” Johnson said. “This is when you expect to see much less.”

Animal-rights activists have been aggressively targeting the 57-year-old company, alleging that the feathers in its parkas and the fur trim on its hoods come from abused geese and coyotes.

Last month, Upton got blasted on Instagram when she praised Canada Goose’s “efforts to make this world a better place,” with one user replying that Canada Goose “literally kills animals for fashion.”

“Trapping coyotes for their fur in horrific leg traps absolutely despicable!” another wrote.

As reported by The Post, the company earlier this year was targeted by the Federal Trade Commission over its claims about its animal sourcing, apparently prompting the company to water them down.

On its website, Canada Goose now says it does “not condone any willful mistreatment, neglect, or acts that maliciously cause animals undue suffering.”

“I think the animal-rights issues don’t help,” said DA Davidson’s Morris.

The company — whose other celebrity customers have included Jimmy Fallon, Emma Stone and Bradley Cooper — hinted at a slowdown in November when it handily beat Wall Street’s estimates on top and bottom with sales up 28 percent, but didn’t raise its forecast for the year.

The company’s shares fell 12 percent, to $34.81, after its earnings report on Nov. 13.