Friday, August 8, 2014

August 7 2014 Ramble Report

Another beautiful morning at the State Botanical Garden, not too hot and not too cold, found 22 Ramblers ready to learn about Hummingbirds. 

But first, we presented Ronnie and Eva, our two
Junior Ramblers, with certificates to commemorate their participation in our rambles this summer. We enjoyed having them present and benefited greatly from their enthusiasm and sharp-eyed powers of observation. We hope they will return in the future.

Don and Emily each contributed a reading today. Don's is from A Short History of Nearly Everything by Bill Bryson; Emily's is from Hummingbird Nest: A Journal of Poems by Kristine O'Connell George. Both readings can be found here.

Today we were pleased to have a guest leader, Judy Glenn, who designed the Hummingbird trail for the State Botanical Garden. This trail consists of numbered Red Markers, each with a Hummingbird silhouette, that are strategically placed in spots all over the formal gardens. Each marked location is where Judy has personally observed consistent hummingbird activity. These are generally places where there are plants that are good nectar sources (Lantana and sage, as well as others). The numbers on each marker correspond to numbered locations on a map of the garden that is available in the Visitor's Center. (Because the maps are in short supply I've taken the liberty of copying one and placing it here on Google drive. My scanner could not accommodate the full width of the brochure, so part of the illustrations are missing. You'll have to pester the garden to get a full sized map.)
Judy is a nature photographer as well as a hummingbird enthusiast and has a blog and a facebook page that display her work.
Judy began by taking a group photo and then playing recordings of Ruby-throated hummingbird vocalizations. She then told us how she laid out the trail and then presented some facts about our local hummingbirds. We have only one species, the Ruby-throated hummingbird, here in Georgia. (There are occasional strays of western species, but these are very uncommon.)  Before she began Judy passed out pennies to a number of ramblers and we discovered why -- a penny weighs 2.5 grams while an adult Ruby-throated hummingbird weighs approximately 3 grams, just slightly more than the penny in our hand! The male Ruby-throats arrive in our area about the middle of March, ahead of the females, and establish territories. Only the males have the brilliant iridescent red throat; females and juvenile males have white throat feathers. As the young males mature they gradually get a sprinkling of red feathers in the throat region. Until then it is not possible to identify the sex of the young birds. The red coloration is not due to pigments. It is a structural color, like the colors seen in soap bubbles. Its appearance also depends on your viewing angle. From the side the throat of a male looks black. The male can move the feathers to flash the brilliant red in the direction he wishes. Ruby-throats migrate to Mexico and Central America in the fall.
Hummingbird nests are constructed from plant fibers like milkweed fluff. These are collected and bound to a tree branch with silk from spider webs. Sue mentioned that she had seen a hummingbird gathering spider webs from her windows -- an excellent reason not to wash those windows. After the bundle of fiber is secured to the branch the female collects bits of lichen and tucks it into the nest, camouflaging it. Then she sits in the walnut-size nest and wiggles and turns about until a suitable depression is formed. She lays one or two eggs, each the size of a small jelly bean. For the previous three years Judy has recorded the last dates on which she has seen hummingbirds in the garden: Oct. 1, 2 and 3.
After these introductory remarks Judy led us through the garden, pointing out favorite flowers
Ramblers looking for hummingbirds
and perching sites at each of the 20 stations on the Hummingbird Trail. Because the hummers don't like large groups of people we caught only glimpses of them along the way; they fled our approach. So after Judy showed us the location of the last station we broke up into smaller groups to observe the hummers without disturbing them.

I'm going to attempt to answer some of the questions I was asked during the ramble, as well as mention some other aspects of hummingbird biology and physiology. Click on the links below if you're interested.

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