Black-chinned Hummingbird Nesting Info

[betsy]

With male Black-chinned Hummingbirds staking out territories in the old fish hatchery at White Rock Lake, some of us naturally wondered if females might be nesting there, and if so, where should we look for such a nest. I just found a great, very detailed page about where and how they build their nests and raise their chicks. As with the Ruby-throats, the males do not assist at all. They stake out territories near food sources after they lose interest in mating.

http://www.hummingbird-house.com/nesting.html

There are some videos of females building nests in the external links section of this Wikipedia page:
http://en.wikipedia.org/wiki/Black-chinned_Hummingbird

ID problems:
Then there's always the problem of how to tell a female Black-chinned from a female Ruby-throated Hummingbird -- not addressed there. See the last photo on this Bill Schmoker page (click on it to get a larger one), its comment and the linked female Ruby-throat photo. Subtle! The Black-chinned appears to have a slightly more decurved bill, too. http://www.schmoker.org/BirdPics/BCHU.html

The USGS Patuxent site says they can't safely be distinguished from female Ruby-throats except in the hand, though.
http://www.mbr-pwrc.usgs.gov/id/framlst/i4290id.html

Kevin Zimmer, in Birding in the American West, says the same, but adds that Black-chinned females seem to have a more gray-green forehead, while Ruby-throats have a greener forehead.

This site, http://hummingbirdworld.com/h/id.htm , says
"Female Ruby-Throats and Female Black-Chins are, for all practical purposes, not distinguishable in the field. If you want to make an educated guess, remember that female Black-Chins usually have a longer bill and they pump their tails [article below in los news says this is significant only when actively feeding, not when getting into position to feed]. ... The black-chinned may be more gray on the crown."

Advances in identification are reflected on Cornell's updated All About Birds site though -- they advise us to "look carefully at the outermost flight feather: it is knife-shaped in the ruby-throat but club-shaped in the black-chinned."

Here's a detailed study of the differences in plumage characteristics between adult female and juvenile Black-chinned Hummingbirds: http://elibrary.unm.edu/sora/Condor/files/issues/v085n01/p0102-p0103.pdf

A detailed discussion of differences between the two species is contained in the Hummer ID Article here: http://losbird.org/los_news_188_99nov2.htm

Another detailed discussion with annotated photos is here:
http://staff.jccc.edu/dseibel/rthu.htm

Photos from several angles with ID tips here:
http://www.dreamsmithphotos.com/birds/black_chinned_female.html

[Weazel]

Betsy thanks for all this info and links. The first article about the nesting I found very intresting. We have had a female hummingbird for about 1 week now coming regularly, and we believe it to be a BCHB. What I thought was more intresting was that their second favorite tree to nest in a fruitless mulburry, which is exactly the tree that takes up half our backyard. So now I want to peek around the tree and try to find a nest.

Recently in the last two days the hummingbird has been absent, at least from observation. I believe the sugar water is decreasing but hard to tell. Do BCHB nest here in the metro or only pass through?

Also if anyone can care to shed any light on if this is a BCHB or a RTHB please let me know. I posted the photo on a Bird Identification group on flickr and came out with two different answers.

http://www.flickr.com/photos/backyard-birder/sets/72157617485125795/

[betsy]

Jason, Jim Peterson wrote me that he's not getting any records of their nesting in Dallas, so I don't believe we know whether they are or not. Obviously, one of the great difficulties is being able to tell for sure if a female is a Black-chinned, since they loook so much like Ruby-throated females. If you can't tell, you can't report it.

It would be interesting to learn if the people who offered an ID for your photo live in the east or the west. I think easterners would be more likely to call it a Ruby-throat and westerners would be more likely to call it a Black-chinned, simply because the only place their ranges are beginning to overlap a little is in Texas, so most people would have an opportunity to see only one species or the other on a routine basis and would probably identify it as the one they were familiar with.

Flickr is probably not the best place to get consistently accurate IDs for a bird, especially when the ID is a tricky one. You don't appear to have mentioned where you photographed the bird, so anyone attempting to give you an ID would be handicapped by not knowing it was in the area where the two species overlap. You seem to have already decided what it is, though, judging by the captions on the photos.

[Weazel]

Well one of the comments I placed on a picture I added to the flickr bird identification pool, I stated it was in Dallas Metro in Texas, but good thinking on the two people and what they are familiar with. I tagged the photos with BCHM because the one person who stated it was pretty confident and gave reasoning so I went with that.

[jpeter]

Well one of the comments I placed on a picture I added to the flickr bird identification pool, I stated it was in Dallas Metro in Texas, but good thinking on the two people and what they are familiar with. I tagged the photos with BCHM because the one person who stated it was pretty confident and gave reasoning so I went with that.


For the record, Black-chinneds are not uncommon nesters from Oak Cliff to Cedar Hill. But once you get off that limestone plateau, you lose them altogether. That's why WR Lake was so unusual as a nesting spot. Most of Dallas County is not Black-chinned habitat, except for the southwestern part. So I misspoke a little when discussing Dallas County in general.

You could almost make an assumption of species based of where in Dallas County the nest was located, but not entirely. The two species would be very difficult to differentiate unless you had a really good selection of photos to choose from.

[Weazel]

Im trying so hard to get some great shots in full light, but no luck due to work. Why can't I just be a proffesional birder! This sat. I plan on hanging out in the backyard all day, so hope to grab some good shots. I have only seen her 2x in the last 5 days. Not sure if its even a different female from before. Hopefully on Sat. ill have news to report. Also spend time sneaking around the mulberry tree very carefully searching for a nest.