Wildlife

Wildlife Wednesday: Costa’s hummingbird found livin’ on a Prairie

Plus: the extinct mega-herbivore that once shaped kelp forests, the rare fern fueling a Cape Breton golf course controversy, the great gray owl's hunting skills revealed, and the continuing crash of Canada's fish stocks despite investment.

A Costa's hummingbird. (Tracey Riddell/Can Geo Photo Club)
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With an average weight of less than four grams, the Costa’s hummingbird is a small but mighty species typically found in the southwestern United States and western Mexico. So when the tiny bird was discovered in a backyard in Saskatchewan, Canada, in mid-October, bird banders were understandably shocked. How did this unexpected visitor get so far outside its typical range? Once in the care of Living Sky Wildlife Rehabilitation, staff identified the species as a young male based on its feathers — an iridescent purple crown, white eyebrow, and purple elongated gorget.

Although Costa’s hummingbirds have been spotted in Alberta and B.C., this is believed to be the first time one has been found in Saskatchewan. The question of how the bird arrived in the province is still unanswered, but staff may be able to find out where it came from through isotope analysis. 

‘Til the cows come home

An illustration of the now-extinct Steller's sea cow. (Photo: Biodiversity Heritage Library/Wikimedia Commons [CC BY 2.0])
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For millions of years, the eating habits of the Steller’s sea cow — a four-ton marine mammal and relative of the manatee — helped shape kelp forests all along the Pacific coast of North America.

Researchers from the California Academy of Sciences have revealed that, by eating massive quantities of kelp fronds from the upper canopies, the now-extinct sea cows allowed light to spur productivity in the lower reaches of the kelp forests. As such, the kelp forests of the 1700s — before Europeans hunted sea cows to extinction — were likely very different to those we see today.

Kelp forests are now in steep decline across the Pacific, and the absence of large marine herbivores like the Steller’s sea cow may be a contributing factor. The researchers tested this by using historical kelp forest data to get a better picture of how they used to be, then modeled how the ecosystem might respond under different scenarios — including the presence of Steller’s sea cows. Their results showed a totally different type of kelp forest, one that was more resilient to conditions such as ocean warming or disease outbreaks. 

The results suggest there may be ways to build resilience into kelp forests by simulating the role sea cows play — such as by selectively harvesting the upper fronds of kelp forest canopies — and that we ought to look further back in time when evaluating ecosystems. 

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Leaf in limbo 

The upswept moonwort normally grows in western North America. (Photo: Tab Tannery/Flickr [CC BY-NC-SA 2.0])
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The discovery of a rare fern at West Mabou Beach Provincial Park in Cape Breton, N.S., is leading to renewed calls to rethink a controversial golf course proposal in the area. Acadia University biologist Alain Belliveau logged the fern in 2018 during a survey that confirmed the existence of 17 other rare and endangered animals, plants and lichens, including four birds. However, he only just got confirmation of the 18th find — the upswept moonwort fern — after sending photos of the unidentified plant to some fern experts. “I wish I had identified that four years ago,” he said in a recent interview with CBC News. “That’s a long time to sit on something that’s such an incredible discovery.” The upswept moonwort, which normally grows in western North America and has never been found in the Maritimes, requires a specific fungus to be in the soil to grow. In other words, the rare fern likely cannot be successfully moved and transplanted if the golf course plan was to go ahead. Belliveau says the find demonstrates the need for continuing biodiversity surveys in the area.

All ears

Photo: jadsonmorais/PxHere
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How do great gray owls locate voles so accurately under the snow and ice? To find out, a team of Canadian and U.S. researchers used buried and unburied loudspeakers to see how snow absorbs and refracts vole noises. They then used an acoustic camera to spatially locate sound sources.

“[Great Gray Owls] actually put on weight over the winter. So, as it gets snowier, they’re getting fatter. That was making us scratch our heads,” says study co-author James Duncan. “As it turns out, they’re supremely adapted to catching prey under snow.”

Their abnormally large facial discs are specially adapted, allowing the owls to hear the low-frequency sounds that pass through thick layers of snow. Once located, the owls hover directly over their prey, as in this position there is less sound refraction and attenuation from the snow, allowing the greatest accuracy. Their great strength then allows them to punch through ice thick enough to support a person’s weight and snatch unfortunate voles beneath.

Stock crash

The spring herring fishery in the Gulf of St. Lawrence was closed earlier this year. (Photo: Chung Kevin/PxHere)
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An independent audit has revealed that Canada’s $120 million efforts to rebuild depleted wild fish stocks are failing.

The 2022 Fishery Audit, carried out by nonprofit Oceana, assessed 194 fish stocks in Canada and revealed that, despite the investment, fewer than one third of wild marine fish stocks in Canada are considered healthy and most critically depleted stocks lack plans to rebuild them.

While 30 per cent are in what Fisheries and Oceans Canada considers the healthy zone and sustainable for fishing, this is down from 34 per cent in 2017. Fifteen per cent are in the cautious zone, meaning fishing should be reduced. The status of a further 37 per cent of stocks are currently uncertain.

Worryingly, 17 per cent are in the critical zone, which means serious harm is occurring to the stock, and very few of these stocks have plans in place to rebuild them.

The audit suggests that one leading issue is the lack of formal consideration of climate change in management approaches.

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