December dragonfly and false Hutton's Vireo

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Joel Geier

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Dec 3, 2021, 1:08:27 PM12/3/21
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At E.E. Wilson Wildlife Area yesterday, a large dragonfly was hunting over the edge of "Playa del Ray," the wetland about 1/3 mile south of the skeet range.

I watched it for about 10 minutes but it never landed, so I couldn't get a detailed look. The overall color seemed to be dark brown with some bluish highlights, so based on general appearance and size I'm guessing that it was one of the Mosaic Darners. Steve Gordon and Cary Kerst's  guide, Dragonflies and Damselflies of the Willamette Valley, Oregon shows two species of Mosaic Darners that are typically observed into mid-November: Shadow Darner (Aeshna umbrosa) and Paddle-tailed Darner (Aeshna palmata).

A few garter snakes are also still active around the area.

Two days ago, also near "Playa del Ray," I heard what seemed to be a Hutton's Vireo giving its monotonous, "Zu-weep!" song. But when I located the bird, it turned out to be a Bewick's Wren, engaging in some remarkable mimicry. We'll need to watch out for that guy on the Airlie-Albany Christmas Bird Count, a month from now. In years past, that same part of the wildlife area use to host a European Starling that gave an excellent imitation of a Sora -- but from high up in cottonwoods!

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Joel Geier
Camp Adair area north of Corvallis

Lisa Millbank

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Dec 3, 2021, 2:11:17 PM12/3/21
to Joel Geier, Mid-Valley Nature
Jim Johnson maintains a list of early and late flight dates for Oregon dragonflies and damselflies on his website, https://odonata.bogfoot.net/, which is more up-to-date than the first Kerst/Gordon book, with several December and January records (see attachment). Maybe Shadow Darner is the most likely candidate for the one at EE Wilson, since there's a late record of December 10 for that species.  The earliest date for Shadow Darner is in May though, so they may not be able to survive prolonged freezing weather.

One species that may overwinter is Variegated Meadowhawk.  There's a late record of one on December 9, and I saw a male in Corvallis on January 3, 2012.  December 2011 had been cooler than average, so he had survived many hard freezes!

Lisa Millbank

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OregonOdonataFlightDates.pdf

Joel Geier

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Dec 3, 2021, 9:15:59 PM12/3/21
to Lisa Millbank, Mid-Valley Nature
Thank Lisa! That's a great resource from Jim Johnson, thanks for sharing!

I was just surprised to see *any* kind of dragonfly in December. From Jim's compilation, it seems like indeed that's rare, even if not unheard of.

From the weather predictions, it sounds like next week around December 11th might finally bring our first real winter weather.

Joel

From: "Lisa Millbank" <millba...@gmail.com>
To: "clearwater" <clear...@peak.org>
Cc: "Mid-Valley Nature" <mid-vall...@googlegroups.com>
Sent: Friday, December 3, 2021 11:10:46 AM
Subject: Re: [MidValleyNature:6322] December dragonfly and false Hutton's Vireo

Richard C. Hoyer

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Dec 10, 2021, 12:44:37 PM12/10/21
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Hi Joel at al.,

I just wanted to point out that Bewick's Wren is not known to mimic, and the very Hutton's Vireo-like call you describe is actually part of the normal repertoire, found in Bewick's Wrens who have never heard a vireo. As far as I know, the only wrens known to mimic, though virtually nothing has been published on it, are the two members of the genus Odontorchilus (Tooth-billed and Gray-mantled), which are aberrant wrens in several other respects as well. Incidentally, Hutton's Vireos along with a few other vireo species, do exhibit a rare type of mimicry sometimes classified as "vocal matching:" one bird will copy the song type of a neighboring individual of the same species, even though each vireo has several different song types that it may sing over the course of the day.

Rich

Joel Geier

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Dec 10, 2021, 1:13:27 PM12/10/21
to Richard C. Hoyer, Mid-Valley Nature
Hi Rich,

My recollection is that Donald Kroodsma documented apparent mimicry by Bewick's Wrens of Vesper Sparrow songs (and vice-versa) at Finley NWR in the 1970s, back when there were still Vesper Sparrows nesting on the refuge. I think he published several papers on this.

Joel

From: "Richard C. Hoyer" <hoyerna...@gmail.com>
To: "Mid-Valley Nature" <mid-vall...@googlegroups.com>
Sent: Friday, December 10, 2021 9:02:49 AM
Subject: [MidValleyNature:6330] Re: December dragonfly and false Hutton's Vireo

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Joel Geier

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Dec 10, 2021, 1:23:48 PM12/10/21
to Richard C. Hoyer, Mid-Valley Nature
P.S. Here's a fun link based on Don Kroodsma's research that describes the same type of "vocal-matching" behavior that you mention for Hutton's Vireo, but for the case of young Bewick's Wrens that incorporate elements of songs of neighboring wrens:
https://americanarchive.org/catalog/cpb-aacip-5ce3a09c91a


From: "clearwater" <clear...@peak.org>
To: "Richard C. Hoyer" <hoyerna...@gmail.com>
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Sent: Friday, December 10, 2021 10:13:09 AM
Subject: Re: [MidValleyNature:6331] Re: December dragonfly and false Hutton's Vireo

Richard C. Hoyer

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Dec 12, 2021, 1:01:24 PM12/12/21
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Vesper Sparrows were found to sometimes mimic, but I think all Passerellidae can do this to some extent. But not Bewick's Wrens.
From one of Kroodsma's papers:

"I recorded and analyzed the song repertoires of 30 Bewick's Wrens at the Finley Refuge, and in addition listened carefully to thousands of songs while studying the behavior of this species. Individual males are highly variable songsters, having from 13 to 20 song types each. Juvenile males learn their songs from adult males, but I have heard no clear mimicry of other species."

Good Birding,

Rich

Joel Geier

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Dec 12, 2021, 1:21:06 PM12/12/21
to Richard C. Hoyer, Mid-Valley Nature
Interesting, Rich, thanks for the follow-up.

From: "Richard C. Hoyer" <hoyerna...@gmail.com>
To: "Mid-Valley Nature" <mid-vall...@googlegroups.com>
Sent: Sunday, December 12, 2021 10:01:23 AM
Subject: Re: [MidValleyNature:6337] Re: December dragonfly and false Hutton's Vireo

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