Hummingbird Charm

Piecing together the mysteries of Ruby-throated Hummingbird migration

Idie Wednesdays

How close have you been to a hummingbird? Do you have a feeder in your yard? Have you been graced by their presence on a walk in the wilderness? These creatures are hypnotic in my opinion and always leave me spellbound. I jumped at the chance to see them up-close-and-personal at a hummingbird banding station with my friend Sandy.

Sandy Lockerman is one of only 200 hummingbird banders in the country licensed by the United States Geological Survey. I met her at Hog Island Audubon Camp. She is also permitted to band Northern Saw-whet Owls and took me to one of her sites last fall. To receive her master hummingbird bander permit, Sandy had to apprentice for years and come recommended by three current banders. “Hummers” are only handled to promote understanding of the species; there has to be research value to the project. All the birds that Sandy bands contribute to her project on migration, stop-over and site fidelity.

After arriving in Harrisburg, Pennsylvania at Sandy and Gary’s wildlife-art-filled home on a sunny Friday afternoon in August, we caught up with each other and played with their beloved cat Ziva.

On Friday night, Sandy filled my mind with all thoughts hummingbirds. She has many theories on the species, including that some birds may stay in the U.S. throughout the summer and never leave the Southern states, instead of migrating over the Gulf of Mexico.

Interestingly, she thinks that she is banding Ruby-throated Hummingbirds (RTHU) hatched in Canada who migrate down to Pennsylvania, New York and Massachusetts. This is because the females have longer wing chords than other RTHU banded by scientists in different parts of the country. Her measurements are consistently flagged as outliers by the Bird Banding Lab, though they are correct.

On top of this, banders in Southern states believe that the bands on RTHU males are falling off because they are too big for their legs. Banders in the south are advocating for 5.6 mm bands instead of the standard-sized 5.4 mm bands. Sandy continues to use 5.4 mm and places a little dab of paint on the head of any males she bands to see if the band has fallen off in the event of a re-capture. Sandy said that only one band in 1,000 has ever fallen off a male at her banding station. She believes that this fact adds to her Canada theory. She points to Bergmann’s rule of ecology which states that populations and species of larger size are found in colder environments, and species of smaller size are found in warmer regions. If the birds she is banding are from Canada, that would explain why their wing chords and legs may be larger than birds from the Southern U.S.

While the Bird Banding Lab supplies bands for all other species of birds, hummingbird banders get to make their own. The Lab now provides sheets of bands which each bander cuts into individual pieces. This leads to questions about standardization of band size and the different equipment that might be used by different banders. This could also account for some of the males losing their bands in the South. Some banders make them in the moment at their banding stations, but Sandy uses snowy days in the winter to hunker down with Ziva and make her bands for the upcoming season. The bands have one letter and five numbers. This individual code is used to identify that individual hummer in the database. The bands are made of soft aluminum and Sandy uses jeweler’s tools to put them together. However, she always brings at least five unsheared bands in case she captures a different species of hummingbird at her site. Each species has a particular size band that it “wears”.

Before 2007, there was no banding data on RTHU in Pennsylvania. Scott Weidensaul began banding and Sandy joined him in 2010. Now, Sandy has over 12 years of data to crunch on the species. She has seen that males have longer tails, but their wings and bills are shorter than females, among many other interesting data points.

On every banding trip, Sandy is accompanied by her husband, Gary, who proudly proclaims that he “builds sh*t” that Sandy needs for her project. He helps to collect and extract hummingbirds and feels no need to obtain his own banding permit, as it would mean two separate sets of bands in their house and a separate project to work on. He has built a number of sophisticated traps which encompass hummingbird feeders. When a bird enters the feeder trap, an expert extractor closes the trap door and safely removes the bird. No birds are harmed during this process. They are then placed in a soft mesh bag and brought over to Sandy for banding. Gary’s traps are remote-operated. Some can even pull two trap doors at once with one controller (using the right and left buttons from an old remote-controlled car). This amazing model is fondly referred to as the Lockerman 2000.

Sandy explained to me we would likely band all hatch-year birds because by August the adult females are off their nests and back in Mexico. Adult males usually leave in the beginning of July.

After Sandy showed me all the tools that we would use the next day at the banding station, we sat down in her home office to go over Hummingbirds 101. With beautiful bluebird paintings on the wall and Ziva laying on the desk in front of us, Sandy showed me her powerpoint used for educational programs.

I channeled my ever-present inner student and took notes, fascinated as I learned from Sandy and also took breaks to pet Ziva. I learned that hummingbirds are the tiniest bird in the world, but have the largest brain for their size and also the largest heart relative to body size. Their feather density is four to five times greater than other birds, which is why they have no down feathers. Sandy explained that hummingbird throats are referred to as gorgets, a French word used to describe the piece of metal armor that sat over a knight’s throat. Hummingbirds are also able to fly so fast in part because their wings are structured to be able to produce a figure-eight-like motion, with power on the down stroke and upstroke, unlike other birds.

Through slow motion photography, it has been discovered that hummingbird tongues are not straw-like as many believe, but actually split and serve as a fluid trap. They are compressed, fringed and forked. Sandy and I talked about torpor and how RTHU weigh about a dime and are about three to four inches long, with males being smaller than females. They follow traditional gender roles, which may explain why females typically live three to four years and males only live two to three years. It is thought that males spend much of their time defending their territory, a more dangerous job than the females’. Sandy also believes that some females may be staying in the southern U.S. and not flying over the Gulf of Mexico, which could contribute to their longevity. RTHU migrate to the Southern U.S., Mexico and Central America. In Pennsylvania, they migrate in the spring around late April/early May and in the fall they are on the move in mid-July/August.

She also mentioned that more and more banders are catching western hummingbird species in Pennsylvania. Sandy believes climate change may have something to do with it. They’ve seen: Rufous, Callilope, Allen’s, Anna’s, Black-chinned, and most notably, a Bahama Woodstar in April 2013 on Mennonite property. Sandy explained that since 2007, they have seen 175 western species in 43 of the 67 counties in Pennsylvania. Most of these birds were Rufous Hummingbirds.


Following the conclusion of Hummingbird 101 (lucky for me there was no exam), we  discussed the details of Sandy’s research project. As mentioned previously, Sandy would not be permitted to band hummingbirds if she didn’t have a project that contributed to the knowledge of the species. Her project looks to answer these questions:

  • Do Pennsylvania landforms such as mountains or waterways (specifically slopes of mountains near streams in valleys) aid RTHU migration? If not valleys, are they using mountains during migration like hawks and bats?
  • Do PA RTHU use the same stopover sites during migration and the same breeding sites? Are there resident populations in early June-July?
  • Where are they coming from and where are they going?

Sandy runs her project as the master bander and does not have any sub-banders on her team. She has two main banding sites: one in Centre County and one in Perry County. Her sites have a 15% and 13% resighting rate, respectively. This means that Sandy is re-capturing birds that she banded prior and is able to glean even more information about their whereabouts and behavior with each year they return.

After gaining a great foundation of knowledge, we went off to bed to get a good night’s sleep before our early morning. We would be traveling about an hour and a half to get to our banding site the next day.

The next morning, we drove along the Susquehanna and Juniata Rivers. Everything was draped in a heavy fog. As we got closer to the banding site, the fog lifted and we saw so many spiderwebs caught perfectly in the morning light along the road. It was both spooky and beautiful. We drove along Penns Creek, famous for trout fishing, and saw an immature Bald Eagle, Belted Kingfishers, Barn Swallows, and Great Egrets. We entered a part of Pennsylvania [VIDEO: Country Roads] where distance is measured in miles not minutes and life seems to slow down.

We arrived at our banding station, the home of John and Jan who were so kind as to let Sandy use their “hummingbird haven” for research. Sandy set up shop and we watched her as she effortlessly banded hummingbirds and spoke to guests who arrived to observe her work. We listened to Northern Cardinals, Carolina Wrens, Eastern Towhees, and Red-eyed Vireos calling over the wind chimes hanging throughout the porch.

Sandy explained that in July/August we have four choices for birds who may be caught in our traps: hatch-year (HY) males and females, as well as, after-hatch-year (AHY) females and males. In order to age the birds, we looked at grooving in their bills. If the bills were smooth, the bird was an adult/AHY. If there were striations, the bird was a juvenile/HY because the striations meant it was still growing the keratin for its bill. Males don’t develop their ruby gorget until later in life, so we used primary feather #6 to sex the birds. If the feather was rounded and webbed, the bird is female. If the feather is scalloped with no webbing it is a male. Sandy and I would love to know who figured that out.

Anyway, we were on our merry way, banding birds and looking out for the start of “big boy feathers” on the young males. Sandy explained that some birds have been returning to the site for three of the last 12 years that they have data for. It is believed that RTHU have yellow mouths when they are young and black mouths when they are older, but we banded an adult female with a yellow mouth that day! The birds are always proving us wrong, which is one of the reasons why bird banding is some important. We measured a number of data points for each bird:

  • Age (hatch year, after hatch year)
  • Sex
  • Wing Chord
  • Tail
  • Culmen (exposed bill)
  • Grooving on bill
  • Gorget Feathers
  • Weight
  • Fat

Throughout the day, we banded 45 ruby-throats, 33 of which were hatch-year, and we had seven resightings of previously banded birds at John and Jan’s home. All our hummers were released safely back into the Pennsylvania wilderness, including this one, who just needed a little nudge from me to get going [VIDEO: release]. Though it was late in the season, there were at least 100 hummingbirds buzzing around John and Jan’s house all day which was a sight to see [VIDEO: hummingbird feeders].

After an unforgettable experience, I’m so looking forward to seeing all that is uncovered about the charming Ruby-throated Hummingbirds of Pennsylvania thanks to Sandy’s great efforts.

2 replies on “Hummingbird Charm”

Thanks for sharing. A member of our Harford County, MD bird club puts up multiple hummingbird feeders around her home. We have been able in past years to watch the banding process done by Bruce Peterjohn who comes up to her home to band. This year the hummingbird population seemed much reduced so no banding.

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