A minor and fascinating observation about male broad-tailed hummingbird roosting habits - sample size of one.
I have always wondered where and when different species of birds roost at night; how that changes as they go from non-breeding season, into breeding, and then back again. For example, great horned owls - the males will typically nest closer and closer to the nest tree as the time of hatching grows closer; do they always use the same tree and branch - or do they vary their daytime roost locations? What is it, specifically structure-wise, that they look for in a roost branch - or is it just any old branch and any location along that branch, and any old tree? It seems as though I stumbled across a unique opportunity to observe a single male broad-tailed hummingbird's roosting habits. This male has setup territory over my flower garden and feeders in my back yard. One night in late April, I was going out to my hot tub after dark. It sits adjacent to a douglas-fir with a branch that extends out to the edge of the hot tub - about 9 ft off the ground. As I opened the cover to the tub, I noticed that I had immediately flushed a male BTHU nearby. Oh well. The next time I went out, the same thing occurred. Hmmm, a faithful roosting location I wondered. The next night, my wife and I went out before sunset so as to possibly catch this male coming to his roost site. We were not disappointed. About half way between sundown and dark, the male came in and alighted on a naked twig on the low branch next to the hot tub. I have mentioned before to others on this group, and had it confirmed from as many about the nesting habits of female BTHUs. Really cannot say where I got this from; my own observations, probably confirmed by BNA or others, or other book sources - just can't remember. But, among the many BTHU nests I have found, they have always had one thing in common; they appear to be on the lower limb of a vertically forked branch; e.g. imagine a branch that has a horizontal fork, both limbs on the same horizontal plane, and rotate it 90 degrees so that both limbs are on the same vertical plane. One above the other. The female chooses the lower branch of the forked limbs to place her nest on. The concept of a "roof over her nest" seems to come to mind. There are other traits I have noticed as well; one in particular is that these nests are often over what you might describe as pathways - e.g. over a trail through the woods, over a creek (which in essence is a trail/opening in the undergrowth), drainage ditch, etc. I can generally pick out a "path under the nest site". Back to the roosting male and his chosen site for roosting and the physical structure of it. First, it is directly over the sidewalk (e.g. path) next to my hot tub that goes around the back of my house leading to my back deck. Second, it is roosting on a small naked twig that curves down (vertical fork) from the main branch (roof over head) that is particularly full of needles. This roost twig curves down for a few inches and then levels out to a horizontal perch. I would describe this as amazingly similar to the female's consistently chosen site for nest building. However, this roost twig is far too small to support a nest, but just the perfect diameter for the tiny male's feet to perch on. As for fidelity, we have been observing this male now for close to 2 months. It always comes to roost precisely halfway between sundown and dark. It always ends up exactly on the same spot on the roost twig. Sometimes, if we are in the hot tub and particularly noisy when he comes in to roost, it will first alight on a branch a few feet above his roost twig, but within a minute or two (after getting comfortable with us) will move right down to the same spot on the same twig; within 3 feet of our heads while sitting in the hot tub. After that, even getting out of the hot tub and closing the cover will rarely disturb it. As I said at the beginning, this is only a sample size of one male BTHU; so your mileage may vary with others. I just find the fidelity to the site, the precise timing of going to roost, and the location/structure of the site being so similar to female nest sites worth documenting and disseminating. Also, since hummingbirds are quite different from other species in that, they don't have a need to nest close to their mate's (many mates') nest sites, it seems to me to show that perhaps his roost site is chosen by proximity to his defended territory rather than any mate's nest - which would (I think) typically drive most other species of birds' male roosting preferences during the breeding season, that have more of a monogamous breeding convention. Hmmm - I wonder where the polyandrous female spotted sandpiper chooses to roost overnight? Hope others find it worthwhile. Jeff J Jones ( <mailto:[email protected]> [email protected]) Teller County - 8500' - Montane Woodlands -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
