[Tweeters] Rufous Hummingbirds
creinsch at humbirds.org
creinsch at humbirds.org
Wed Jul 31 14:46:05 PDT 2013
Thank you for posting this. Questions about missing hummers come up every year here and on other birding sites, and it is good to hear from someone that has observational history of more than a few years. We have only been luring hummingbirds to our yard since 2002, but have, every year, had Rufous in addition to resident and ranging Anna's. We see almost exclusively immature Rufous late in the season, but have on a couple of years had an adult visit for up to a week in April. Rufous do not linger with us however - they have business elsewhere.
I wonder if the combination of hummers' tendency to revisit known grazing sites and their relatively short lives might account for people watching their feeders to perceive occasional decreases in attendance. Hatch year hummers not having yet identified sites to revisit may range wider and wander into urban gardens, but a plentiful source of food in the coastal flight path might discourage urban exploration.
One other comment, the Rufous we have observed are little jets compared to the lumbering stogy Anna's. They can out fly and out maneuver the Anna's, and are relentless in returning to a food source they crave. (crave?)
magnolia, seattle, wa
----- Original Message -----
From: David Hutchinson
To: tweeters at u.washington.edu
Sent: Wednesday, July 31, 2013 1:27 PM
Subject: [Tweeters] Rufous Hummingbirds
During my hummer study in the early 1980s and in observations in Discovery Park since that time, I have found no evidence that Anna's Hummingbirds are replacing Rufous. Rather the two species appear to intersperse themselves. Anna's first-nest in February and March, while Rufous are still arriving. Then it is Rufous turn to breed. In fact at feeders, Rufous appeared to dominate Annas while they are in-migrating, just by pure numbers. Furthermore, while Rufous may certainly use feeders - as like most at least northern latitude hummingbird species -they are opportunistic.
Rufous, whose migration routes and feeding patterns have evolved over thousands of years, breed based on the availability of forest understory & edge plants, such as Salmonberry, Orange Honeysuckle, Red Columbine etc , with which they have co-evolved so that these plants are hummingbird pollinated. While I do not say that Rufous do not feed in gardens and that Annas do not feed at native plants, I am sure that the majority of Annas Hummingbird sightings in Greater Seattle are in backyards with a diversity of ornamental flowering plants - more opportunism at work here!
Funnily enough, while I am sure that day length and hormonal development are triggers for Annas breeding season, it also is true that the bloom of Red-flowering Currant, as early as the beginning of February, may also stimulate them.
I do know that some Annas double clutch, though I do not know the story for Rufous, though it is quite possible. Certainly Rufous males start clearing out as early as the beginning of July, perhaps while their females re-nest. Again their second nesting must surely follow Annas' second nesting, avoiding competition, though perhaps more by accident than by resource competition.
Again in the spirit of opportunism, there are a surprising number of flowers that both species visit throughout the summer months. My sense was that feeders were not necessarily important for hummers in those months. Now I have a question for y'all.
David Hutchinson, Owner
Flora & Fauna: Nature Books
Discovery Gardens: Native Plants
3706 Corliss Ave North
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