Re: [cobirds] Gray, er, Canada Jay imitations?

All - 

With regards to Swainson Hawks breeding in that area, The Second Colorado Breeding Bird Atlas shows SWHA as probable in the SW portion of Hinsdale County (west of Rio Grande Reservoir) as well as possible in the eastern half of the county.  Two years ago I had an adult SWHA on CO149 south of Spring Creek Pass on July 6th (I was quite surprised as it was over 10000').

As for Canada Jays and their ability to mimic, I have been thrown for a loop a couple of times with one imitating Northern Goshawk.  One time I spent 20 minutes trying to visually locate the NOGO and when the culprit finally showed itself, it was gray, but that's where the similarities ended.  Stinker!

Good birding,
Kathy Mihm Dunning

Denver

On Sun, Jul 14, 2019 at 9:36 AM Eric DeFonso <bay.wren@gmail.com> wrote:

Hi folks,

While doing my last-of-the-season Bird Conservancy survey a couple days ago at 11,500 feet in the Rio Grande NF southwest of Lake City, I heard what sounded to me like a Swainson's Hawk somewhere to my east during midmorning. I thought briefly, "Awesome! I don't get those often on surveys, and this is really high up for one." It was hard to scan the sky in that sunny direction but I didn't notice any hawk circling above. What I did note though was a minute later hearing Canada Jays making familiar-sounding squawks and squeaks. I'd seen a few of them in the same general area some time earlier, and I put two and two together and then thought I'd probably been fooled by a corvid once again, this time an unlikely culprit. I'm not aware of any elevational records for SWHA above 10,000 feet, although I suppose that's certainly possible. This area is characterized by spruce-fir forest of course, but also rather vast stretches of high-elevation grassland meadows and willow patches.

I wanted to submit this question to the collective experience of COBirds, and ask if anyone out there has ever heard Canada Jay imitations of any kind, and specifically of Swainson's Hawk. What I heard was a textbook SWHA keer call, clear and drawn out and without any quivery quality to it, given twice. For what it's worth, Birds of North America Online has this to say about CAJA imitations:

"The Canada Jay is previously reported to imitate Northern Pygmy-Owl (Glaucidium gnoma; 62), Rough-legged Hawk (Buteo lagopus) and Merlin (Falco columbarius; 29), and Pine Grosbeak and Red-tailed Hawk (Buteo jamaicensis; 93). Also gives excellent imitations of Broad-winged Hawk (Buteo platypterus), American Crow (Corvus brachyrhynchos), and Blue Jay, sometimes when the imitated species is in sight, but more often in plausibly stressful situations (e.g., human near active nest; bird just released after banding; DS). Imitation of Merlin's high-pitched tremolo was conspicuous in 2001–2002 on Anticosti Island, Quebec, where this predator is common. Merlin imitations were unknown before that in Algonquin Park, but increasingly heard since then, perhaps resulting from local recovery of formerly extirpated Merlin population (DS). As with Blue Jay (163), most species imitated by the Canada Jay are known or potential predators of adults or nests; mimicking predators could serve as a warning call to other group members, to confuse the predator itself, or merely to signal in a general way that a threat is present."

Which leads to me then ask, if CAJA is imitating SWHA, why? When would their ranges ever overlap enough for a SWHA to be a likely predator for CAJA nests? Or could I have heard an actual SWHA in that lofty habitat?

Thanks for sharing your stories and knowledge!

Eric

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Eric DeFonso
near Lyons, Boulder County, CO

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