Sunday, June 10, 2012

Hummingbird Science

I was recently invited to observe science in action at a home high in the hills above the Methow Valley. 

I've always been fascinated by hummingbirds; Frank and I refer to the feeder as "hummingbird TV." Consequently, I jumped at the opportunity to see how the little guys are caught, measured and banded.  

Thanks to Mary Morgan and Phil Millam for posting photos last year on Facebook, and for kindly introducing me to Dianne Edmonds so I could photograph this year's study and interview master bander Dan Harville for a Methow Valley News story. 

The following is the text of that story from the June 6 issue.

Valley birds part of international hummingbird study

            The deck of Dianne and Rick Edmonds’ A-frame cabin in the upper, Upper Rendezvous, became hummingbird central last weekend when a team of master banders arrived to continue an annual hummingbird banding study that began in 2009.
Homeowner Rick Edmonds operates the trap under supervision of a master bander.
            Hundreds of hummingbirds are briefly captured from the Edmonds’ deck over a two-day period each year. The birds are lured to a feeder within a net trap and each is gently transferred by hand to its own small flannel bag where it waits to be weighed, measured, banded, and examined for presence of body fat, an egg, or signs of molting. After no more than two minutes “in hand,” each bird is set free to fly away and tidy its tiny rumpled feathers.
Dan Harville examines a male rufous hummingbird while Rick Edmonds observes.
            Master hummingbird bander Dan Harville and Jan, Dan’s wife and data recorder, band hummingbirds under the aegis of the North American Bird Banding Program, jointly administered by the United States Geological Survey and the Canadian Wildlife Service. Harville lives in Edmonds, Wash., and is one of two master hummingbird banders in the state. There are fewer than 100 master bander permits in the whole United States.
            Harville said that the Upper Rendezvous is a good location for hummingbird migration study because there are simply a lot of birds there.
            “Hummingbird migration flows over the land like an ocean,” Harville said. “The birds that you’re seeing are just a small portion of what’s out there.”
Male calliope hummingbird displays iridescent neck feathers. 
            Of the three species of hummingbirds that are generally found in the Methow Valley - calliope, rufous and black-chinned hummingbirds - only the mountain-loving calliope and rufous were captured on Sunday morning up in the Rendezvous, although black-chinned would be observed lower down on the valley floor, and around the Columbia Basin, Harville said. Our local species may migrate as far north as Southeast Alaska in the summer. They winter in Mexico.
            A generally non-migratory population of Anna’s hummingbirds has resided year-round in Western Washington since the mid 1960s, Harville said. They are rarely found east of the Cascades.
            Around 110 birds were captured and released from the Edmonds’ deck during two two-hour sessions on Saturday evening and Sunday morning (May 26 and 27). About 15 to 20 percent of those were already sporting bands, and had returned to the same location where they had been banded previously, Harville said.
Applying the band. Harville said, "It helps to be near sighted."
            The federal Bird Banding Laboratory supplies the tiny, numbered aluminum bands that are placed on captured hummingbirds’ legs, and keeps the master database of records that are gathered around the United States and Canada.
            Harville fashions the bands himself from stamped aluminum strips that he orders from the Bird Banding Laboratory. Hummingbird bands are numbered differently from other bird bands because they are so small. A batch letter - Harville was working with batch “L” - is stamped into the metal followed by five numbers.
            Over the years, four birds banded by Harville have been captured by other banders, one each in Texas, California, Louisiana and Colorado. Harville himself has captured a bird on Whidbey Island that had been banded in New Orleans, and another in Cle Elum that received its band in Colorado.
            He said he had personally banded over 5,000 birds before one was recorded in another location. Now that the figure has doubled to over 10,000 birds banded by Harville, “exchanges” - having one of “his” birds captured by another bander - seem to be happening more often, he said.
            Banding is a necessary part of the study process, and in an experienced person’s hands is safe, Harville said. He admits that it is inherently dangerous to handle the tiny birds; they could be sick or low weight, for example. But after banding 10,000 birds, Harville says with certainty that only one died during the process.
            “It was an immature bird, slow, and struggled constantly during handling,” Harville said.
            Now if a bird struggles, Harville works quickly to band it and let it go without measuring or weighing it.
            “Banders do it because they like birds and want to know more about them. It just doesn’t make sense not to be as careful as possible,” Harville said.
Paint mark prevents handling the same bird twice.
            Each bird that is handled gets a yellow paint dot on top of its head so that if it ends up in the trap again - about half of Sunday’s birds were “retraps” - it is immediately freed so it doesn’t get handled twice. The paint mark might last until the bird molts, which happens right after breeding, Harville said.
            Each captured bird is swaddled in a customized flannel cloth and weighed. An average adult calliope weighs 2.6 grams; a penny is 2.5. The bill length, tail length and wing chord length - distance from the wrist to longest primary feather - are measured.
A stream of air exposes the skin to check for body fat and/or an egg.
            The presence of eggs or body fat - the latter indicating the bird is storing energy for migration - are determined by blowing a stream of air onto the bird’s chest feathers to expose the skin. Age can be determined in the first and second years by the presence of hatch-year feathers and striations on the growing bill.
            Harville figures that one cup of nectar per day feeds 50 to 60 birds. At one busy banding location - Hyak at Snoqualmie Pass - they went through two gallons of nectar one day.
            “Sitting there among the feeders was like being in a bee hive,” he said. “There may have been 10,000 birds at Hyak on that particular day.”
            Because hummingbirds ingest so much water in nectar - many times their body weight per day - they may have the most efficient kidneys of the animal kingdom, Harville said. They also eat bugs - aphids, gnats and small spiders - for protein.
            Hummingbirds in the Methow are breeding now. The adult male leaves as soon as the female is on the nest in mid-June. The female busily brings bugs to her growing hatchlings until they have fledged in mid-July; then she leaves. The young birds eat and store up fat until they start to leave on their southern journey around the middle of August.
            If a banding station elsewhere in the United States or Canada captures a banded bird, the number is reported to the national database so migration patterns can be established. And any person who finds a dead bird with a band can report the finding at, and participate in ongoing research.
Measuring tools dwarf the little hummers.


  1. Thanks so much, Laurelle, for posting your report from the Methow Valley News. The photos are great, and I learned so much about these amazing creatures! They're Mickey's favorite bird in the garden. Ever since we redid our yard and planted lots of Salvia, we get hummingbirds galore. Is there any way to see a band without capturing a bird? Sometimes they sit perched for a while in a tree or on the branch of a bush, but I've never taken the time to watch them through binoculars...

    1. Couldn't you just watch them all day? Of course you have many more species in San Diego than we have up here. I told Dan Harville that we visit San Diego frequently, and he said most of the hummingbirds you see there are year-round residents, with a few migrants that pass through on their way up the coast.

      Those bands are awfully small. You might be able to spot one with binoculars ... Let me know if you see a banded one!