I've spent the last few days observing the action at the hummingbird feeders in my yard in eastern Sacramento County. The hummingbirds we typically see here are the resident Anna's Hummingbird
and the Black-chinned Hummingbird, a migrant that breeds locally and winters to the south.
The Rufous Hummingbird breeds as far north as southeast Alaska and its fall migration normally takes place in the western mountains where the last blossoms of the summer fuel the tiny bird's journey.
My yard is not on a major migration route so I was quite surprised to see a Rufous Hummingbird at the feeders.
The bright gorgets of the adult male hummingbirds make identification easy, but the females and hatch-year birds can be very difficult to distinguish in the field; one must often rely on details like the shape of certain tail feathers which are not easily observed without having the bird in hand.
Female and hatch-year Rufous Hummingbirds are nearly indistinguishable from the closely-related Allen's Hummingbird but Steve Hampton (
http://www.tertial.us/yolobirds/yolo.html) was able to deduce from these photos that the bird in my yard is most likely a Rufous Hummingbird.
On home territory hummingbirds can be very territorial, and even the Rufous Hummingbirds claim and defend temporary feeding territories in the sheltered mountain valleys that form their migration path.
Hatch-year males typically begin growing their showy gorget feathers by the end of summer so the extent of gorget plumage growth allowed me to identify as individuals several of the male hummingbirds and thus establish a minimum number of birds visiting the feeders. I was able to count a minimum of 4 male Anna's Hummingbirds and also 4 male Black-chinned Hummingbirds. Add the Rufous Hummingbird and the Anna's and Black-chinned females and there have been a minimum of 10 hummingbirds at the feeders.
My two hummingbird feeders are one-holers so not everyone can feed at the same time. Dawn and dusk are the most active times at the feeders, dawn because the birds have been fasting all night, and dusk to top off the fuel tank to get through the night with energy reserves.
Competition for the feeders is intense and combat for space, both inter-species and intra-species, is the norm. Only twice did I observe feeder sharing, both times involving two female or hatch-year Anna's Hummingbirds. A few times it looked like a couple of hummingbirds had agreed to a truce and were going to share a feeder when a third (or more) hummingbird declared war on both and disrupted the peace.
Ten+ hummingbirds fighting over two feeding ports is chaos! The single Rufous Hummingbird was dominant followed by a hatch-year male Black-chinned Hummingbird and an adult male Anna's Hummingbird. Some of the less-dominant birds adopted a stealth strategy, lurking in the shadows waiting for a foolish or gutsy hummingbird to test the dominant bird's resolve. The resulting battle often sent the dominant bird in pursuit of the fool to the neighbor's yard allowing the lurker to sneak a sip.
Without further verbiage, the photos:
Rufous Hummingbird:
Black-chinned Hummingbird, hatch year male (note the violet feather growth on its throat):
Anna's Hummingbird adult male:
Female or hatch-year Anna's Hummingbird threatening another hummingbird:
All photos: Leica R8 with DMR digital back, Leica 280mm f/4 APO-Telyt-R. All comments welcome.