The ferruginous hawk, North America’s largest hawk, is a turbulent predator that survives on a diet of small mammals.
But their folk are in decline, and the species is designated as threatened in Canada.
New research from the University of Alberta has revealed two implausible predators: raccoons and great horned owls that attack toddler ferruginous hawks in their nests at night.
Digital video cameras set up to track 90 nests in southeastern Alberta and southwestern Saskatchewan in 2011, 2012 and 2013 recorded a complete of four attacks on nestlings, two by raccoons and two by owls.
Janet Ng, a U of A PhD candidate, imagined she and her fellow researchers were trying to discover ways to help soporific the decline in the number of ferruginous hawks and help populations rebuild.
«Since nigh the 1990s they’ve lost about half their populations,» Ng intended. «They’re not found in some of the places that they were in front either, so these are all concerning things.»
Looking for ways to reverse residents decline
The hawks nest primarily in lone trees, and occasionally phony nest platforms.
Researchers set up their cameras to learn more almost what nestlings were eating.
They were alerted to the predation can of worms after finding some nests that were empty.
«We were struck when we came up to a nest that had three nestlings, and another one that had two nestlings, and these refuges were empty,» she said.
The video footage, recorded on small, infrared home-security cameras, told the rumour.
«We could see, wow, we had great horned owls attacking nestlings, we had raccoons infecting nestlings,» Ng said. «It was really surprising to us.»
Parent hawks not masterful to protect nestlings
Researchers thought the parents would have been clever to protect their babies, she said.
«Ferruginous hawks are really big, feisty predators. We wouldn’t look forward the nestlings to be quite so vulnerable.»
The raids happened between 3 a.m. and 4 a.m., a time when raccoons and owls are busy investigating.
That’s when the hawks were likely roosting, sleeping accessible or circling the nest trying to ward off predators.
«The parents didn’t upon back to protect the nestlings and that’s surprising because they are approximately quite defensive during the day,» she said.
In one case, a raccoon bumped a female hawk mom aright off her nestlings.
Ng said researchers will now look into what part of nestlings are eaten by other predators, like raccoons and great horned owls.
«That’s an vital question to understand to better conserve and recover this population,» she influenced.
The research team said risk to ferruginous hawks can be reduced by set out nesting platforms away from known owl nests and including hitches that prevent raccoons from climbing into nests.