It is essential for birds to keep their feathers clean. Hummingbirds bathe frequently and in ingenious ways. They use rain, sprays of water such as from a water fall, bathe in pools of water on rocks and leaves, fly into and sliding around on wet leaves and moss.
Courtship Rituals and Mating
Female hummingbirds build the nest, lay the eggs and raise the young alone. The male only provides the genetic material needed for reproduction. The female goes in search of a male when her nest is nearly complete. She will leave her nesting area in search of a male. When she encounters a male, he will greet her with a display of vocalizations and diving. If she is impressed, she will remain in the area as he moves closer, flying back and forth flashing his gorget (throat feathers) showing is virility. After mating, the two birds part ways. The female returns to her nesting area to complete the nest and the male waits the arrival of another female in his territory.
Hummingbirds feed mostly on the nectar of flowers. They are often found at red or orange tubular flowers such as trumpet creeper, cardinal flower, honeysuckle, jewelweed, and bee-balm, but will feed from many different blossoms of various shapes and colors. The choose nectar quantity and quality over flower color. Their beaks and tongues are perfectly adapted to retrieve the sweet liquid. Tree sap is an ideal alternative to nectar because like nectar, sap is contains sucrose, water, and amino acids in relatively the same proportions. The ruby-throated hummingbirds’ spring migration follows that of the sapsuckers’. The hummingbirds arrive at their nesting grounds several weeks before any flowers are in bloom. They are able to obtain all the energy they need from the sap produced by the efforts of sapsuckers. Sap wells also serve as refueling stations during fall-migration. Hummingbirds visit feeders containing sugar water too. A hummingbird needs to consume more than its body weight in nectar each day. This requires thousands of visits to flowers and feeders. Hummingbirds also need proteins, fats and other nutrients that nectar or sugar water cannot provide. They eat many types of small, soft-bodied insects and arachnids to fill their protein needs.
The shoulder joint, wing structure, and large flight muscles allow the wings to move in a figure-eight motion resulting in the ability to fly forward, straight up, straight down, backward, and hover. The unusual ability to hover and flight backward is crucial for obtaining nectar from flower blossoms. A hummingbird’s size, ability to rise vertically and depart instantaneously gives the illusion of exceptionally fast flight. Their top flight speed is 25 miles per hour. Their speed during escape and courtship dives can more than double their flight speed.
Chemical changes, length of daylight, as well as insect and flower populations play a role in hummingbird migration. A hummingbird will gain 25-40% of their body weight before they start migration. Hummingbirds migrate north in the spring to their breeding grounds and arrive in the southern states in February and the northern states in May. They migrate south to Mexico and Central America in the fall beginning in August and lasting through October. Males arrive in their seasonal homes before the females. The first thing all hummingbirds will do upon arrival at their destination is fatten up. When the males arrive at their breeding grounds, they will establish a territory and begin looking for females. When the females arrive they will start looking for the best mate and nesting location. Though hummingbird migration occurs on the same common fly zones, they migrate alone. They fly generally south until they reach the Gulf Coast. Then many of them fly over the Gulf, nonstop, to the Yucatan. Others hug the coastline rather than take the long overwater flight. They fly during the day and sleep at night. However, when the ruby-throated hummingbirds are flying over the Gulf of Mexico, there is no place to land to rest, an incredible 20-hour nonstop journey of more than 500 miles.
When a hummer visits a flower, it inadvertently picks up pollen and transports it to a different flower. However, not all flowers visited by a hummingbird get pollinated. A hummingbird can drink nectar from a shallow blossom without picking up any grains of pollen.
Reproducing and Raising Young
Nest building, incubating the eggs and feeding the young is the responsibility of the female. A typical hummingbird clutch contains two eggs laid a few days apart. The female selects the nesting area and builds the nest before mating occurs. She will not reuse a previous year’s nest, but will often build a fresh one in the same area. The nest is roughly the size of a walnut shell made of spider silk, plant down (thistle, cattail, and dandelion) and camouflaged by lichen.
Incubation, the time it takes for the eggs to hatch, is influenced by how much time the female spends on the nest each day and the weather in the nesting area. When the chicks hatch, they are feed regurgitated insects by the female. The young develop rapidly and outgrow the nest and leave it when they are 18-20 days old. The female continues to feed the fledglings for a few weeks.
Hummingbirds have the highest energy output per unit of weight of any warm-blooded animal. They are tiny birds that use a huge amount of energy. To supply the needed energy, they must feed every few minutes, and they survive the night without food by going into a state of modified hibernation, torpor. In torpor, the resting heart rate drops, respiration becomes shallow, and temperature plummets. A hummingbird can save up to 60% of their available energy this way. It may take more than 20 minutes to fully recover from torpor. Then the first order of business is food.