Re: [cobirds] Broad-tailed Hummingbirds ARE double-brooded!

Nice work, Dave,

It's good to see Citizen Science in action!

Larry Modesitt

Greenwood Village

On Jul 7, 2017, at 7:10 PM, DAVID A LEATHERMAN <daleatherman@msn.com> wrote:

Today I think I saw proof that Broad-tailed Hummingbirds can have two broods at low elevation.  The evidence that they do has been highly suggestive for years, but without banding or otherwise marking individual females, proof has been difficult to acquire.  At Grandview Cemetery in Fort Collins (Larimer) about a half hour ago, I tracked down a fledged hummingbird making that strange chirp they make for only a few days after leaving the nest.  Nathan Pipelow, you still need to record this.  Or I need to take a tutorial on how to do it with my Smarterthanitsowner Phone.  At any rate, I finally located the bird making its directionless chirp from a dead juniper branch.  Soon it was fed by an adult female.  This went on for some time: chirping, occasional visits from the adult.  After one of these feedings (when my dumberthanitsownerwhenitsverylowlight camera wouldn't autofocus, dammit) the adult calmly went over a few feet AND SAT ON A NEST!!!!!!!!!!  I did not know about this nest.  Furthermore, this was not a nest that still contained the sibling of fledged Youngster #1.  This was a pristine nest and the adult female was obviously sitting low as if on eggs or getting ready to produce eggs.

     <gc bthummer doublebrood 098ec.JPG>         <gc bthummer doublebrood 100c.JPG>

Left photo shows fledged young hummingbird.  Right photo shows this bird being fed by parent female (lower leftmost bird in photo).

                                          <gc bthummer doublebrood 104ec.JPG>

Same female as involved in the feeding shown above sitting on new nest about 5 feet from where the feeding took place.

Earlier in the visit today I was shown a nest in a backyard just east of the cemetery that had a sitting female.  In Section D of the cemetery I knew of a nest that had just experienced egg hatch.  What I found today were two 1 day-old young attended by no female hummer but rather the kinds of insects that eat carrion.  Both these nests are more evidence that second-brooding is ongoing but do not constitute the proof that the situation in the first paragraph and photos does. 

So, I think this verifies what I've been trying to prove for many years.  The "Birds of North America" account for this species of hummer, which says double-brooding does not occur at high elevation in the mountains but is suspected at low elevation but unproven, was written based on information mostly gathered at Gothic, CO (i.e. near the upper altitudinal range for this species).  Maybe in Gothic at present two broods are not possible or normal, but I think at 5000 feet ASL it is happening and has probably been happening for a long time.

Dave Leatherman

Fort Collins

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