Harrison's new decoys are about 15 percent smaller than the ones he made before. Those were big birds, as big as the largest-known ivory-bills. David Ligon of the University of New Mexico said they were too big for the job, which was to taunt territorial ivory-bills into coming down and driving away the interlopers.
He was right, Harrison said, sounding mildly rueful that he hadn't thought of it himself.
"A bird is not going to pick a fight with something it's not going to win," he said.
So these four - there will be two male and two female; the females don't have the red-crests - are smaller. A wire snaking from the bird to a battery pack will be disguised as a vine, he said.
Sunday, September 24, 2006
Harrison's new robotic Ivory-bill decoys
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4 comments:
I wish Harrison would go away with all his goofball ideas, and I'm a believer.
The idea that a bird would not antagonize a larger bird or enter "a fight it could not win" is completely untrue and most birders should know this. In order to band local raptors for my research project, I have used a live great horned owl as a lure to trap many raptors of several species in the vicinity of the nest of the target bird. I have used this technique personally to trap American kestrels, short-eared owls, northern harriers, red-shouldered hawks, and Swainson's hawks. Most of the targeted birds were smaller than my great horned owl, but aggressively interacted with my owl in a process known as "mobbing" in order to defend their nest and young. In the same scenario, I have seen countless passerines, hummingbirds, swallows, and other birds also engage a live great horned owl.
In fact, it seems like the larger the raptor targeted for this sort of trapping, the weaker the response from the nesting birds.
Likewise, one can regularly see conspecifics going after intruders of either sex and all sizes during the nesting season. If a male peregrine falcon sees a larger intruding female, he will give chase, and if unsuccessful, he may return to his eyrie and alert the female who will then go and also interact aggressively with the intruding female.
All of these are things that birders see routinely during the nesting season.
How Bobby Ray Harrison can assume that a smaller than life model would provoke stronger defense is a question only he can answer. But if the model is smaller than the real threat, it stands to reason that the model would not provoke a reaction because it is not threatening. Nest defenders do not spend energy and effort attacking non-threats; you don't see scrub jays in California harrassing red-winged blackbirds -- it works the other way around.
Stan Moore San Geronimo, CA
How Bobby Ray Harrison can assume that a smaller than life model would provoke stronger defense is a question only he can answer.
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This is because Bobby is not a birder and not an ornithologist. He is an Ivory-billed Searcher. It is a breed unto itself
"A bird is not going to pick a fight with something it's not going to win," he said.
Unlike, say, a IBWO believer ...
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