Friday 26 June 2015

[cobirds] Recent Miscellany (Weld and Larimer)

I think I posted about the Loggerhead Shrike larder on the Pawnee (Weld CR37 north of CR114).  This will be the subject of the next "The Hungry Bird" in "Colorado Birds" (October 2015) so I'll not detail this event too much here.  Suffice it to say a lot of items of great diversity can be impaled in the vicinity of just one shrike nest, probably by just one male.  What impressed me the most about this particular situation near the Central Plains Experiment Station was the heavy use of birds, including "naked" babies obviously pulled out of nests.  With the lush green growth and certain pastures solid yellow with blooming Greenthread (thanks, Amber Carver for the ID) it is easy to mistake this year's prairie as a tranquil place.  Predators on vertebrates are having a bumper year right along side, and often because of, the herbivores and insectivores.

At Grandview Cemetery in Fort Collins (Larimer) I am aware of 4 active Broad-tailed Hummingbird nests.  I thought I heard the gibberish of a Black-chinned male the other day but am not certain.  The broadtail nests are in various stages of development, from still under construction to eggs to almost fledged young.  As reported earlier, one nest (the 5th 2015 nest at GC and there are probably at least a few more, making this a true "colony" like the literature reports them as having) is totally done and I think I heard the fledged youngsters giving that distinctive "warbler-like" chip they make that I don't think anyone has recorded.  I have enjoyed seeing the diversity of materials the female hummers use to craft their work-of-art nests, both the cup itself and the outside decoration/camo.

In Lower Rist Canyon (Larimer) yesterday I heard an Ovenbird sing briefly one time at around CR52E mp 15.  This is a historic location for them and despite the 2012 High Park Fire they have persisted in a mostly unburned north-facing glade.  Most of the usual suspects that indicate this a nice lower montane habitat were there including Plumbeous Vireo, Hammond's Flycatcher, Pygmy Nuthatch and Red Crossbill.  American Three-toed Woodpeckers nested here one spring/summer but all I saw yesterday while insect-collecting was a flicker and Hairy Woodpecker.

Further down Rist Canyon (east of the famous "Whale Rock") I watched a parent pair of American Robins capture and take to a nest several 2/3s-grown caterpillars of the White-lined Sphinx.  These "hornworm" (big spine on the rear of the abdomen) caterpillars, which are highly variable in color from mostly green to mostly blackish may be locally abundant in coming weeks.  Lots of vegetation for this eater of a broad range of plants to consume this year with all the rain.  They might even be conspicuous as they cross roads in large numbers looking for additional food or pupation sites.  I would love to hear from COBIRDS readers about what birds they see eating these, including the date and location.  Refer to "The Hungry Bird" article about them for more details (CB Vol48(4), October 2014).

We have started an informal group in Fort Collins to monitor Chimney Swifts.  Our initial goals are to just figure out most of the active chimneys (or other places) and get a handle on early summer numbers.  Hopefully we can then get some numbers from later in the summer that might reflect nest production, and then additional use of roost chimneys in fall by migrants.  Untimately, we would like to determine trends and maybe do some enhancement with artificial nest structures to keep a sustainable population of these fascinating urban providers of free control of West Nile mosquitoes and maybe other pesky insects.  I would encourage other cities and towns to maybe do the same.  We sucked them into the idea of chimneys being "better" than hollow trees.  If they are in trouble, seems like we owe it to them to be part of the solution, too.

Dave Leatherman
Fort Collins

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