Forget the Robin, returning Ferruginous Hawks are the true harbingers of spring

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Each spring, Ferruginous Hawks return to the Canadian Prairies from their wintering grounds and our research team is ready to greet them. These provincially endangered and federally threatened Hawks return from the United States and Mexico in mid-March, when they form pairs and build their nests.

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“Everything went South for Ferruginous Hawks” Southward migration paths for 11 Ferruginous Hawks monitored using GPS satellite telemetry in 2012 and 2013.

Ferruginous Hawks generally return to the same territory and nest as the previous year, but this isn’t always the case. Some nests are used for 10+ years and others are abandoned after only one year. Understanding what influences their habitat selection between years could be crucial for their habitat conservation.

Our team heads out first thing in the spring to tour southern Alberta and Saskatchewan. We check on historical Ferruginous Hawk nests and seeing who has returned home. Encountering a spring snow storm is pretty typical for our early spring field work, but it’s nothing that North America’s largest Hawk can’t handle.

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A FEHA nest in a spring snow storm. That nest looks pretty cozy to me.

Sometimes Hawks choose to nest in a new spot because they had a lousy run the previous year. Our study has found that Hawks that had a successful nest the previous year are more likely to come back and use the same nest. Hawks that didn’t fledge any young were more likely to change nests the next year. This means that, like many bird species, Ferruginous Hawks will hedge their bets. If they did well last year, they’ll try the same thing again. Last year was terrible? They’ll try something new and hope for the best.P1P4

A female Ferruginous Hawk sits in the nest prepared for another breeding season. You get pretty good at identifying Hawks from just their foreheads, which are sometimes the only thing visible through a spotting scope 300 m away.

Other factors can also influence re-occupancy of nest. Winter storms can knock nests out of trees and other species will even steal a Ferruginous Hawk’s old nest. We’ve encountered Great Horned Owls, Red-tailed Hawks, Swainson’s Hawks, Common Ravens, and Canada Geese in old Hawk nests.

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A female Great-horned owl incubates her eggs in a nest which was occupied by Ferruginous Hawks in previous years.

Our team’s research will be ongoing throughout the summer of 2014 with the ultimate goal of improving Ferruginous Hawk conservation and management strategies. But, in the meantime, we are happy to already confirm nearly 200 “Ferrug” nesting attempts this breeding season!

Stay tuned for more updates,

Cameron Nordell, Jesse Watson, and Janet Ng

Our research group is the Raptor Ecology and Conservation Team (REACT) in Dr. Erin Bayne’s lab, partnered with Dr. Troy Wellicome with Environment Canada.

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