Science

Watch: Female Hog Island Osprey Defends Remaining Chick From Great Horned Owl

Having already lost two chicks to the raptor, Rachel has been remaining close to the nest and on high alert in a fascinating display of adaptation.
By Andrew Del-Colle
Digital Editorial Director, ÃÛèÖAPP Magazine
Published July 21, 2017

It's been a dramatic two weeks for Rachel and Steve's family. Early last weekÌýa Great Horned Owl attacked in the middle of the nightÌýand took a chick from the Osprey couple's nest at ÃÛèÖAPP's Hog Island in Maine. Then, a few nightsÌýlater, it returned for seconds. Even for a nest camÌýthat has capturedÌýitsÌýshare of nest attacks and ³ó¾±²õ³Ù´Ç°ù¾±³¦Ìý³¾´Ç³¾±ð²Ô³Ù²õ, this has been an especially eventfulÌý12Ìýdays.Ìý

Since theÌýattacks,Ìýviewers of the cam, which is hosted by Ìýhave been anxiouslyÌýwatching to see if the owl would strikeÌýagain andÌýRachel would be able to protect the lone remaining chickÌý(as noted in our story about the first attack, male Ospreys don't usually defend their nestsÌýat night). In response to the attacks,ÌýRachel has stuck closer to the nest, and that paid off last nightÌýwhenÌýpresumably the sameÌýGreat Horned Owl returned for round three.ÌýThisÌýtime, though,ÌýRachel was ready.Ìý

As can beÌýseen in the video above, the clip opens up almost rightÌýaway with an attemptedÌýattack that Rachel manages to thwart. Then, at the 2:57 mark,Ìýthe Great Horned Owl appears in the background, landingÌýin the bough of an evergreen toÌýsurvey the situation. After a full minute, it takes wing again, disappearing from view. Rachel, who is sitting on the edgeÌýof the nest,Ìýclearly spots the bird, though, as she begins loudly emitting her warning calls. The owl swoops in anyway and attempts to land on a large limb sticking out from the nest, only to be chased away. Undeterred, the owl returns again at 5:45Ìýfor one more attempt. But Rachel digs her talons into its back and once again defends the nest.ÌýIt's not clear if the chick was harmed during theÌýattacks, but it at least got to surviveÌýto see another Hog Island sunrise.Ìý

While it's been captivating to watch this saga play out,ÌýRachel'sÌýadaptations to the attacks are illuminatingÌýin anÌýevolutionary and biologicalÌýsense. WeÌýonce again askedÌýSteve Kress, who works on Hog Island and is ÃÛèÖAPP'sÌývice president of conservation andÌýdirector ofÌýseabird restoration program, for his thoughts on this latest news. Here's what he wrote back in an email:Ìý

"There is a lot of insight about how individual predators learn new and ingenious ways to capture prey.ÌýWhat is surprising here is that Rachel seems to be learning new ways to defend her remaining chick. Predator-prey interfaces are often thought to be driven by selection favoring specific behaviors that then become genetically hard-wired, but if Rachel is changing her behavior by perching lower and closer to her chick, it appears she is learning from her experience and adapting her behavior to be a more successful parent. The camera is once again showing new and very exciting insight to bird behavior."Ìý
Considering the owl clearly realizes that there's one remainingÌýmeal in thisÌýnest, there's a good chance that this isn't the last time Rachel will have to fight it off.ÌýHowever, she might not have to keep up theÌýdefense for too much longer. Last year's broodÌýfledged in early August,Ìýand this chick isÌýgetting very close. If Rachel can keep the owl at bay, theÌýchickÌýmight just be able toÌýleave thisÌýnest—and allÌýits drama—far behind.Ìý
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ÃÛèÖAPP is a nonprofit working to save birds and theÌýplaces they need. To support our conservation efforts, Ìý
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