Hummingbirds

Only available on StudyMode
  • Topic: Hummingbird, Ruby-throated Hummingbird, Male
  • Pages : 8 (2893 words )
  • Download(s) : 98
  • Published : April 11, 2013
Open Document
Text Preview
Hummingbirds

Male hummingbirds are the tiniest warm-blooded animals on the planet. Females need to be a tiny bit bigger to be able to produce eggs, to afford to share their body heat with the eggs while incubating, and to be able to share their food when feeding nestlings. Hummingbirds are the smallest birds in North America, and they only exist in North America, measuring between two to five inches in length. They got their name because of the sound created by their wings, which sometimes sound like bees or other insects. How do hummingbirds communicate?

Hummers communicate with one another primarily by chittering and other vocalizations and by flying toward one another aggressively, to chase each other away. Chirping: The outer tail-feathers of male Anna's Hummingbird vibrate during display- dives and produce a loud chirp. When courting, the male ascends about 60feet before diving over an interested female at high speed (35 to 60mph) and producing a high-pitched sound. Experiments showed that the birds could not make the sound when missing their outer tail-feathers, and that those same feathers could produce the dive-sound in a wind tunnel. The bird can sing at the same frequency as the tail-feather chirp, but its weak syrinx (vocal cord) is not capable of the same volume.

Hummingbird flight
Hummingbirds are amazing to watch. They are able to fly up, down, forward, backward, sideways, and even upside down. In hovering flight, the wings move forward and backward--not up and down--and trace a figure-8, with lift being produced by both the forward AND backward strokes. Normal wing beat rate is about 80 times per second, up to 200 times per second in courtship flight. Hummingbirds are famous for their aerial display. Some displays are courtship displays; other displays are aggressive. They are able to perch and will do so at feeders regularly, but because they fly so much, their feet are poorly developed. They can barely walk at all. The hummingbird is much more comfortable in flight. HUMMINGBIRD FLIGHT BEHAVIOR Hummingbirds are incredibly aerobatic and able to hover and fly backwards--even upside-down--and attain respectable forward speeds of 25mph or more during straight-line migration. Hummingbirds reach maximum velocity almost instantly after leaving a perch, and they do not push off with their legs as many birds do. Likewise, when returning to perch, they stop almost instantly. It has even been said that the female hummingbird returning to a nest puts down so quickly AND gently that she is already incubating before her wings are folded. Beyond hovering, the most remarkable aspect of hummingbird flight is endurance. When migrating hummers depart from Florida or the Texas Gulf Coast toward the Yucatan Peninsula, there's no turning back, and there’s not any fast-food stops along the way. At an average rate of 25mph, it takes a hummingbird about 20 hours to fly the 500 or so miles across the Gulf of Mexico, an astounding feat for an organism that weighs--even after putting on fat--only about 5-7g (about the weight of 3 quarters). The muscle fibers in hummingbird pectoral muscles are 100% of the red type (the opposite of the kind of muscle fibers in "white meat," in chicken and turkey pectoral muscle). This enables hummingbirds to keep a rich supply of blood and oxygen flowing into their muscles as they fly, so they don't tire even with their rapid wing rate.

How can hummingbirds hover in one place: When a bird flaps its wing forward it creates forces called 'lift' and 'thrust', which move the bird up and forward. Hummingbirds can rotate their wings backward, which creates downward 'lift' and backward 'thrust'. By alternating flapping their wings forward and backward, the up and down forces and forward and back forces cancel each other out, so the hummingbird hovers in one place.

All hummingbirds are fully grown and capable of flight when they leave the nest; there are no "baby...
tracking img