There are currently 5 active Broad-tailed Hummingbird nests at Grandview
Cemetery in Fort Collins. Two are in Austrian Pine, two are in Colorado Blue
Spruce, and one is in a Douglas-fir. I saw two youngsters in each of these
today, 4 of of the 5 involved females, and heard one male. That's 15
individual Broad-tailed Hummingbirds that should trip a filter in eBird but
probably won't. Seems like that only happens when it shouldn't. I digress.
The cemetery is about 40 acres. I know of 5 nests and suspect at least 2-3
more. Over the last few summers my guess has been that around 10 nests occur
in the cemetery and the first block of homes to the east that I include in my
normal walkabout. The term "colonial" has been applied to the nesting habits
of BtHummers and I think Grandview fits the definition. For example, two of
the nests I am currently aware of are in pines adjacent to one another, with
the trunks being maybe 15 yards apart. Two nests last summer in the southeast
corner of the cemetery were almost this close together.
I have seen two behaviors with the hummers I don't really understand and that
are not at all explained by the BNA account for this species. I am beginning
to regard this BNA account as lacking in a lot of areas, if only because it was
based on observational data mostly from the Rocky Mountain Biological Lab in
Gothic, CO at an elevation of 8900 feet ASL.
1) On 6/22 I saw what appeared to be a female (no dark gorget) doing the big U
or J-shaped courtship dives above an open-grown honeysuckle bush where
presumably another hummer was watching. Pyle's ID Guide to NA Birds says young
male hummers should have a rosy gorget by April, so I do not think this was a
young male bird doing the dives. No mention in BNA of females doing the dives
unless I was misinterpreting some sort of agonistic behavior toward an unseen
threat (snake?) hiding in the bush.
2) Today I watched a female conduct a feeding of two young in her nest. As
soon as this was complete, she appeared to fly down within 10 yards of the nest
to a patch of small-flowered thistles going to seed along the ditch. I say
"appeared" because there is a slight chance a second female was present, but I
don't think so. Hovering among the thistles, the bird grabbed a big wad of
"fluff" and flew directly southwest toward a small group of big spruce trees.
She flew back to the thistles and repeated the fluff run three times. It
looked like she was building a nest across the way, while also carrying out
duties at a nest with two offspring. BNA states double-brooding has not been
documented for BtHummingbird. Sheri Williamson states in her Peterson guide,
"Typically 1 brood per year in central Rocky Mountains but probably 2 broods in
warmer areas." It was 101 degrees in Fort Collins day before yesterday.
Obviously, nothing is mentioned about whether a second nest is started while
the first one is on-going. There is no mention of this species building dummy
nests, although over the years I have seen a few beautiful, fresh nests that
for whatever reason never got used.
Of the 30 or so BtHummer nests I've seen at Grandview, until this year, only
one was built atop live needles. Typically a nest is built on a bare section
of downward-angled branch, with the nest being attached to needleless wood.
The one exception to this was in an area subjected to increased irrigation due
to an attempt by the cemetery crew to establish grass under the dense shade of
a wall-to-wall spruce clump. The female not only chose to protect her nest
with a live bough overhead (as almost every hummer nest does) but blocked a
direct hit from the sprinklers shooting up from below by building atop the live
bough. Smart and effective. I suspect the second live-bough nest found this
year is by the same female, as it is within 10 yards of last year's live-bough
nest, only this year's work of art is considerably higher above the ground (15
feet this year vs 5 last year).
No Pine Siskins detected for the last couple weeks. It appears they raised one
brood at Grandview and headed to the mountains for Brood #2.
Red-breasted Nuthatches are making food runs to their second brood in a cavity
in silver maple. As is customary for this species, the rim of the cavity is
plastered with copious conifer pitch, presumably to discourage nest predators
like squirrels, jays and grackles.
One forlorn Chipping Sparrow has been singing the last few visits but appears
to be running out of time and steam in his quest for a 2016 mate. No Chipping
Sparrow breeding at Grandview this year, unlike the last few.
No Western Wood-Pewees, Ruby-crowned Kinglets, or crossbills either this
summer, as can be the case on occasion.
The Bushtit nest across the street from the cemetery entrance apparently had a
tragic ending at the paws of a squirrel or talons of an accipiter. Something
ripped it apart. One Bushtit was heard about a block away from the nest site
today at a yard with heavy vegetation and feeders (aka Bushtit Trauma Rehab
Center).
Dave Leatherman
Fort Collins
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