Re: What a Sighting!

Clearly I spoke beyond my knowledge.  I remember that in the first year or two of Rod’s project, a migrating HY whopper was taken by  a GOEA.  Because this happened so early in the project, I guess I thought it was a regular occurrence over the decade+ project.  Thanx for setting the record straight Ruth (& Wendy).

Re: What a Sighting!

I was interested in the discussion of eagle predation on cranes and the suggested role of that predation in the ultimate failure of the Grays Lake whooping crane project.  That project was created and run by my late husband, Rod Drewien, long before we met. 

He concluded that the project failed because the number of fledged whooper chicks that survived to breeding age was not adequate.  And, among those that did survive, they showed little interest in pairing with their own species. His hypothesis was that they had imprinted on the sandhills that raised them rather than on their own species.  No one had tried cross-fostering before and  he did not know if imprinting issues would cause a problem.

Rod’s blood pressure would soar when talked about how he could not reduce the mortality of the chicks that did make it to fledging.  I’ll never forget his photo of a recently fledged dead whooper chick that had become entangled in one of the many Refuge barbed wire fences on one of it’s first flights.  That incindent led to removal of a many miles of Refuge barbed wire fences in the pastures  and modifications of their grazing system.     Rod was always emphatic that grazing on the NWR, which many conservationists opposed, was essential to substitute for bison grazing.  Cranes need large amounts of short grass habitat in the marsh system for foraging and evolved with large grazers.  Flipping over cow pies to eat the insects beneath is also an important food source of protein.

But Rod could not overcome the vulnerability of cranes to collisions with wires, be they powerlines or fences. Some apparently learn to avoid them, many die in their first collision.

I contacted Rod’s long-term project assistant Wendy Brown who is now retired from USFWS and asked her if there were any data regarding eagles killing whooping cranes.

Her reply:

“I don’t have the statistics at hand, but I absolutely am certain eagle predation was not a major factor.   I’m pretty sure Rod actually observed a kill by a golden eagle on a young whooper in flight.   Golden eagles were always on the lookout for the unwary sandhill OR whooper.
 
But — power lines were indeed a major factor — the major factor.   But eagle predation, while it may have had some unknown effect on disappearance of chicks, was not.   
 
Because all birds were radioed and carefully tracked, we had a pretty good handle on causes of mortality.”

Cranes evolved with eagles, and Bald Eagles were likely the most common species near their marshes.  But it’s the thin wires that humans string across their flight paths that cause the most mortality.  Wendy and others have published some good articles on how this mortality can be reduced in key sites with various powerline markers.  Those lines can also be deadly to swans and many in eastern Idaho have been marked over the years.

.

10th Dean Hale Woodpecker Festival registration

Idaho birders, 

Announcing an Oregon Birding opportunity. Judy, jmeredit@…

East Cascades Audubon is pleased to announce that registration opens Saturday April 9 at 8 am PDT for the 10th Dean Hale Woodpecker Festival headquartered in Sisters, June 2-5offering 14 guided tours in search of 11 different species of woodpeckers and 200 other birds. More information: www.ecaudubon.org/dean-hale-woodpecker-festival or DHWF2022@…

_._,_._,_

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Re: What a Sighting!

Great thread here! One wonders if there’s a fitness disadvantage those predators may see that we can’t? Of course, we do see that the prey birds are isolated as an individual or pair, in a normally flocking species. And I like the background on the Gray’s Lake Whooping Cranes – remember journeying over to see them in summer, pre-migration. Early 80s I believe.


Jim Lyons
jflyons@…
208-340-0533

Re: What a Sighting!

I have a falconer friend who carries a pistol on his hip with blanks to fire and try to scare Golden’s or other raptors away from the bird he is flying.

It makes sense for the Bald Eagle to go after a crane in the air since their beak would be a less formidable weapon than it is on the ground … yeah I get a little over analytical watching raptors … but that must have been amazing to watch.

On Apr 2, 2022, at 6:30 AM, lcarrigan_55 via groups.io <lcarrigan_55@…> wrote:


Exactly, was surprised to see that a bald eagle was the predator. Know a falconer who has lost several of his peregrines to golden eagles over the yrs! And, have personally witnessed a golden chase balds away from a carcass. 

But, they’re all predators & suspect the lone pair of sandhills just presented too much temptation to pass on. Perhaps, the sandhill cranes were young, last yr birds & not as wise in the ways of predator avoidance. In any case, was fascinating to witness.

Brian

Ken Miracle
chukar28@…
208-570-2780
“Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God” 2COR 3:5

Re: What a Sighting!

Well, I’d say that’s an equally good sighting! A goose is more maneuverable in the air than a crane. I’m thinking the fact that yours was a lone goose & my sighting was a lone pair, may have presented too tempting target. As opposed to trying to take a member of a larger group. Perhaps, what we’ve witnessed is more common than realized! 

Brian

Re: What a Sighting!

Great dream … thinking of all that I saw in 70 years of wandering in the outdoors before I took up photography and after but did not get it 🙂 Jeff’s dream could save me a lot of $ in camera gear 🙂

On Apr 2, 2022, at 12:38 AM, Jeff Brough <brogjl@…> wrote:


[Edited Message Follows]

Very cool !!  Things like that are practically a once in a lifetime event.  I always have loved the moments in nature that are seen but not captured, and there have been many for me. While I have managed to photograph a few, they are so rare, and happen so fast it’s impossible to catch except in one’s own memory.  I am patiently, hopefully, waiting for the technology that will allow one to print photos directly from their brain to paper, thus allowing for the most elusive moments to be shared with everyone.  “It is a dream, I have” …..
  Jeff Brough
  www.flickr.com/j-brough/albums

Ken Miracle
chukar28@…
208-570-2780
“Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God” 2COR 3:5