Conservation

Hog Island Osprey Chick Snatched From Nest by Great Horned Owl

Despite this year’s use of stylized mannequins to deter predators, Steve and Rachel's nest was attacked once again.


Just seconds before the attack in the early morning of July 25, Rachel spotted something in the distance. She flapped her wings, shifted her weight, and almost left her perch overlooking the nest, but it was already too late. 

With Rachel still peering into the darkness, a Great Horned Owl silently swooped in and grabbed a hold of her chick Dion. The mother Osprey barely had time to react before the owl and her baby were gone. For the next two hours, she stayed in the nest with her remaining chick Halley before returning to her branch where she keeps watch.

For the fifth consecutive year, a chick has been taken from Osprey couple Rachel and Steve, who reside on Hog Island Audubon Camp. The chain of events was captured on Audubon and explore.org's nest cam

This is the ninth year Rachel and Steve have returned to the island to nest, and in that time they have gained a loyal following of cam watchers. But beginning in 2015, eight of the 13 chicks that hatched have been taken by Great Horned Owls or Bald Eagles. Although it’s become a regular occurrence, observers are still shocked to experience the loss of a young bird they’ve breathlessly watched grow up.

“I was disappointed and saddened by the reality of losing a chick that was getting so close to fledging,” says Steve Kress, executive director of the National Audubon Society’s Seabird Restoration Program, “but I also know that predation happens, and that owls are very effective and smart.” 

The attack took place less than two weeks before Dion and Halley were expected to fledge. Kress had been “warily hopeful” that they would survive, given that previous years’ attacks took place in early July. But he also noted that predators are rewarded a meatier meal if they wait for the chicks to grow bigger.

“The Ospreys capture prey, and likewise, so do Great Horned Owls,” Kress says. “Predators are neither good nor bad; they’re just doing what they’re so well-adapted to do.”

Rachel and Steve lost both of their chicks in 2015, and have continued to lose at least one of their two to three hatchlings each year. The annual attacks have pushed the Hog Island team to interfere and “think out of the box and try something different,” Kress says. 

Last year the team took action after two hatchlings were taken by Great Horned Owls. To protect the last chick, the team set up a mannequin, hoping predators would perceive it as a real human and stay away. The successful fledging of that chick encouraged the team to expand the strategy this year with a “Manny Family” of three.

Now, as a part of the official 2019 Predator Deterrence Plan, three mannequins stand on the lawn, illuminated with a floodlight at night. Another light shines on the nest to give Rachel a better opportunity to sight predators. By changing the outfits, altering the postures, and moving the location of the mannequins each night, the team aims to sustain the elements of deception and fear for predators. 

The goal was to come up with a “minimal plan” that keeps predators away without hurting them, as Hog Island is a sanctuary for Great Horned Owls and Bald Eagles, too, Kress says.

The team predicts that there is a good chance the owl may return and is working to amend its strategies so that it can more effectively keep Halley safe. The evening following the attack, an audio element was added to the deterrence plan with hopes of discouraging the owls from coming back.

“The owl has learned by now that the mannequins, which have been there for several weeks now, aren’t real,” Kress says. “When we have a setback we don’t give up, we just try to modify. It’s kind of a discovery-as-we-go approach, and I think that’s the nature of adaptive wildlife management.”

As for whether the Hog Island team should be interfering in this natural process at all, Kress says that the benefit of observing the birds is justification enough.

“People are engaging and learning about the lifecycle of Ospreys,” Kress says. “But it all comes to an abrupt end when the chicks are taken. We want people to see the entire family life from the return of the birds back in April to the fledging of the young.”

One notable moment happened in early July, when the team noticed that Rachel returned to the nest one day with a limp in her left foot. As Rachel stayed in the nest to heal that week, the team saw Steve step up his participation in parental duties, bringing in more fish for the family and spending more time in the nest to feed and care for the chicks.

“This is the stuff we would not see if a predator took the chicks,” Kress says. “We continue to get new insights, even after many years of observing, about how these wild birds are living."

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