Hello,
You may recall a recent post to COBIRDS from Tom Litteral in Steamboat Springs describing the response of Bohemian Waxwings to insect hatches on the Yampa River. I posed an unfair question to my aquatic insects expert buddy Dr. Boris Kondratieff at CSU concerning what he guessed the insects making up the hatch might be. He guessed midges (family Chironomidae) and perhaps the winter stonefly Capnia vernalis.
After my posting to COBIRDS about Boris's guesses, I got a report back from Tom. Tom inquired of a local flyfishing guide in Steamboat about the nature of the hatch and his response was "midges on sunny days, a species of mayfly (Baetis sp.) on cloudy days". This same guide also reported during a previous hatch waxwings landing on the tip of his flyrod and using it as a perch from which to launch aerial foraging attempts over the river. What a great photo that would have made!
Tom also mentioned that part of the almost-every-winter waxwing attraction to the Steamboat Springs area is its widespread serviceberry crop (Amelanchier alnifolia, mostly). This, in addition to juniper berries.
Rachel Hopper volunteered to try catching some of the hatch insects when she went up last week during a Spring Break skiing visit. Rachel successfully captured about 10 insects she said were in the process of emerging from the Yampa River surface on a sunny day, and that Cedar Waxwing were the bird involved (she saw no Bohemians). Boris identified Rachel's specimens as both males and females (representing the two sizes, Rachel) of a single species of chironomid midge in the subfamily Diamesinae, genus Diamesa. Determining the exact species would have required microscopic examination of genetalia which would have required more of Boris's time than I was willing to request.
So, it appears serviceberry berries and juniper berries are one foundation of winter waxwing attraction to nw CO. Midge hatches on sunny days are part of it, and there are probably other aquatic insects (mayflies and stoneflies) involved on cloudy days. Cloudy days often involve snow storms, and it would seem high protein foods like insects on such stressful days might be particularly important to birds. The trick is figuring out where and how to get them. Waxwings of both species are among the avian species that have done this. Very interesting.
I appreciate the contributions of Tom, Rachel, and Boris in piecing this story together.
Dave Leatherman
Fort Collins
You may recall a recent post to COBIRDS from Tom Litteral in Steamboat Springs describing the response of Bohemian Waxwings to insect hatches on the Yampa River. I posed an unfair question to my aquatic insects expert buddy Dr. Boris Kondratieff at CSU concerning what he guessed the insects making up the hatch might be. He guessed midges (family Chironomidae) and perhaps the winter stonefly Capnia vernalis.
After my posting to COBIRDS about Boris's guesses, I got a report back from Tom. Tom inquired of a local flyfishing guide in Steamboat about the nature of the hatch and his response was "midges on sunny days, a species of mayfly (Baetis sp.) on cloudy days". This same guide also reported during a previous hatch waxwings landing on the tip of his flyrod and using it as a perch from which to launch aerial foraging attempts over the river. What a great photo that would have made!
Tom also mentioned that part of the almost-every-winter waxwing attraction to the Steamboat Springs area is its widespread serviceberry crop (Amelanchier alnifolia, mostly). This, in addition to juniper berries.
Rachel Hopper volunteered to try catching some of the hatch insects when she went up last week during a Spring Break skiing visit. Rachel successfully captured about 10 insects she said were in the process of emerging from the Yampa River surface on a sunny day, and that Cedar Waxwing were the bird involved (she saw no Bohemians). Boris identified Rachel's specimens as both males and females (representing the two sizes, Rachel) of a single species of chironomid midge in the subfamily Diamesinae, genus Diamesa. Determining the exact species would have required microscopic examination of genetalia which would have required more of Boris's time than I was willing to request.
So, it appears serviceberry berries and juniper berries are one foundation of winter waxwing attraction to nw CO. Midge hatches on sunny days are part of it, and there are probably other aquatic insects (mayflies and stoneflies) involved on cloudy days. Cloudy days often involve snow storms, and it would seem high protein foods like insects on such stressful days might be particularly important to birds. The trick is figuring out where and how to get them. Waxwings of both species are among the avian species that have done this. Very interesting.
I appreciate the contributions of Tom, Rachel, and Boris in piecing this story together.
Dave Leatherman
Fort Collins
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