Ruby-throated hummingbird on her nest (Ty Ivey/Georgia Nature Photographers Association)
By Terry W. Johnson
The ruby-throated hummingbird’s nest is by far the most amazing nest built by any bird that breeds in Georgia. When you gaze upon one, it is difficult to imagine that a bird weighing little more than a penny can construct something that is truly a work of art.
In the world of the ruby-throated hummingbird, the female, in addition to laying the eggs, is totally responsible for building the nest, incubating the eggs and feeding the hatchlings. In Georgia, ruby-throats nest twice a year. That means adult females accomplish this task this twice each breeding season.
After mating, the female ruby-throat begins the arduous process by selecting just the right place to build her nest. Sometimes a female will refurbish a nest she built the previous year. Nests are usually in deciduous hardwood trees such as yellow poplar, sweetgum, maple, oak, hackberry and beech. However, the list of trees used is not limited to those named here. For example, the birds will also nest in pines. In fact, the first ruby-throated hummingbird nest I ever saw was in a loblolly pine.
Nests are built anywhere from 6-50 feet above the ground (the average is 10-20 feet). Female ruby-throats like to affix their nests atop slender, gently sloping limbs and branches growing along the outer edges of a tree. Often, the nest will be under a canopy of branches and leaves. Ruby-throated hummingbirds also have a propensity for selecting nesting sites above streams, as well as along the edges of openings (including lawns) and the shorelines of lakes and streams.
For some unknown reason, these birds occasionally nest in strange places. For example, one observer found a ruby-throat nest on the stem of a smooth sumac. The stem was broken off about 22 inches above the ground. The nest spanned the broken stem and a shoot that sprouted about an inch below where the main shrub had been snapped. A Flovilla couple had a female ruby-throated hummingbird fashion her nest atop the head of a ceramic angel that adorned a wind chime hanging on their porch. And one spring a Warner Robins family was surprised to discover a ruby-throat nest in the links of a chain holding up a wind chime. Hummingbird nests have also been built on wires, fence posts, extension cords, strings of Christmas lights and even on porch lights.
Ruby-throated hummingbirds do not nest in colonies. On the contrary, their nests are usually no closer than 60-70 yards apart.
Construction begins with a female attaching bud scales and other tiny bits of plant materials with spider webs to – usually – a tree limb. In some instances, the bird will even use pine rosin to glue the nest to a branch. The slender silk found in tent caterpillar nests is also used in construction. The bottom and sides of the nest are comprised of a variety of materials, such as the down found on dandelions, thistles and other plants. However, bud scales are a key component of ruby-throat nests.
Each item used is meticulously wrapped with spider webs and attached to the nest, making the structure both strong and flexible. The whole process requires the tireless female to make innumerable trips to collect plant matter and spider webs. For that reason, when you spot a female hovering near the spider webs under the eaves of your home, there is a good chance she is collecting pieces to help build her nest.
The female uses her tiny body to help shape the nest. She will actually stomp her feet on the floor of the nest in an effort to stiffen it. She shapes and smooths the rim of her creation by pressing it between her chest and neck.
The cup of the nest is lined with soft, light materials such as plant down. Hummers will also use bits of cotton provided by hummingbird fanciers in hummingbird nesting balls hanging in backyards.
Before the nest is complete, it must be adorned with lichens. It is thought this is done to camouflage the nest and its contents. Hummers also use moss for this purpose. It appears that ruby-throats prefer using the scaly, blue-green lichens that grow on the sunny sides of trees. Often these lichens are plucked from trees growing near the nest.
Interestingly, flakes of light green paint have been found in hummingbird nests. Did the birds mistake these flakes for lichens? Who knows?
The whole process takes anywhere from one to 10 days. Nests built on the remains of former nests require less time than those built from scratch.
When this masterpiece is completed it is probably much smaller than you ever imagined. Here are the average dimensions of a typical ruby-throated hummingbird nest: outside diameter, 1-1.75 inches; height, 1-2 inches; inside diameter, three-quarters to 1 inch; and depth, three-quarters of an inch.
This amazing creation has been called Mother Nature’s crown jewel. It would be hard to argue that it does not deserve the title.
Terry W. Johnson is a retired Nongame program manager with the Wildlife Resources Division and executive director of The Environmental Resources Network, or TERN, friends group of the division’s Nongame Conservation Section. (Permission is required to reprint this column.) Learn more about TERN, see previous “Out My Backdoor” columns, read Terry’s Backyard Wildlife Connection blog and check out his latest book, “A Journey of Discovery: Monroe County Outdoors.”