Tuesday 8 September 2015

[cobirds] Grandview Cemetery, FtCollins (Larimer) on 9/8

While today's visit to Grandview Cemetery in Fort Collins at the west terminus of Mountain Avenue was very slow and produced one of the lowest species counts ever (13), it did include three noteworthy events:

A flock of an estimated 25 Bushtits marauding through the area, checking out everything from honeysuckle to American elm to bur oak to lilac to Colorado blue spruce.  Now you see and hear them, now you don't.

A pair of Barn Swallows feeding 4 nestlings under the Laporte Street pedestrian bridge over the ditch midway along the north edge of the cemetery.  Colorado's Breeding Bird Atlas I book lists the range of "nest with young" as 12May-12Sept.  I think these young will still be in the nest past this coming Saturday (12Sept) but we shall see.  In any event they are at the extreme end of things for this species.

The pair of Great Horned Owls are showing signs of interest in each other again.  Per custom, one bird (the male?) takes up a daytime roost in the champion honeylocust in the middle of Section 8 every late summer.  Also per custom most years, it is joined by another owl, presumably the female.  Today was the first day I've seen two owls in the monster honeylocust.  They start out the way they were today, perching several feet away, and by mid-fall are usually sitting virtually shoulder-to-shoulder.  If it proceeds as in the past, as the weather cools they roost in various spruces that are progressively closer to the American Elm in Section H that has been their home for almost two decades.  Since last spring's nest failed, apparently due to flooding of the nest crotch when it contained hatched young, it will be interesting to see if they are still so enamored of their old home.  Site fidelity is strong among GHOs when a particular location has been successful, but, likewise, failure is also a strong influence.

Also, I should mention on 9/5 at Grandview Cemetery I heard that odd warbler or Brewer's/Clay-colored Sparrowlike call given only by recently-fledged Broad-tailed Hummingbirds for a few days after they leave the nest.  An adult female was in attendance, visiting this calling youngster at fairly frequent intervals.  I believe this is quite suggestive of not only late nesting but also supports the notion certain individual females are, indeed, double-brooded.  First evidence of nesting this year at Grandview Cemetery was recorded on 30April when a female was observed building a nest.  That's 4mo9days ago (131 days).  A nesting cycle for BtHummingbirds is 37-45 days.  The BNA account for Broad-tailed Hummingbird says double-brooding, while known for some hummingbirds, is unproven for Broad-tails.  For the early-arriving females, it appears there is certainly enough time for double-brooding.

Dave Leatherman
Fort Collins

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