In the 2007 edition of "Finding Birds in Southeast Arizona," Broad-billed Hummingbirds (Cynanthus latirostris) are listed as "rare" in winter - which, in fact they are overall. However, in the foothills of the Santa Catalina Mountains on the northern end of Tucson, it is not uncommon to see them in many washes throughout the winter. My discovery of a nest in a small wash in northeast Tucson on 2/23/2009 led me to wonder: is this early?
(Click on the pictures for a much larger image!)
Most migrants do not show up for another few weeks, and many of those birds begin breeding in mid-April. I wonder if the individuals that winter in Tucson stick around so that they can get a jump start on nesting? By nesting earlier than the migrants, they could take advantage of the first flowers of the season. Warmer days seem to be upon us earlier than usual this year, so that would make sense: these winter residents are well aware of that fact, and got to nesting in a hurry!
I waited about 15 minutes at a good distance so as not to disturb this nesting bird. When she decided she was ready to leave the nest for a bit of foraging, I dashed in and grabbed this quick picture. You can just barely see a tiny bit of egg sticking out from the lower rim of the nest in the foreground!
I'll check for early nesting facts in the Arizona Breeding Bird Atlas when I get back to my home library, but in the meantime here is a nice summary of the breeding biology of these hummers:
"In Mexico most Broad-billed Hummingbirds are resident, but in late spring and summer many individuals migrate to extreme northern Mexico, portions of southeastern Arizona, southwestern New Mexico, and the Big Bend region of southwestern Texas to breed. In these areas breeders inhabit riparian zones of arid canyons, usually below 2,000 m, which contain sufficient resources to support nesting for up to 5 months. Breeding behavior of females is typical of other hummingbirds except that nests are constructed low to the ground and rarely decorated with lichen."
Powers, Donald R. and Susan M. Wethington. 1999. Broad-billed Hummingbird (Cynanthus latirostris), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/430