BIOD43H3 Lecture Notes - Lecture 14: Hummingbird, Cockatiel, Parasitic Drag
Lecture 14: Movement in fluid (air) III Part 1/2 of Notes
Metabolic Power Available for Flight
Hummingbirds can aerobically power flight at many speeds, including hovering.
*Hovering means moving at 0 m/s (staying in place)
• Humming birds can hover for a long period of time, indicating that it is an aerobically powered
behavior.
• Humming birds do not have a lot of anaerobic build reserves
• Humming birds can fly fast (15 m/s)
Pigeons
• Can not hover for long, only during take-off and landing.
• Do not have sufficient aerobic power to meet power demand to fly at 0 m/s
• Sustainable flight range is in the middle
• Anaerobic reserve used when flight is too fast or too slow
Vulture
• Big bird, that cannot hover in place.
• They have low range of speed used for flapping flight, very narrow
California Bird
• Very large bird
• Aerobic power cannot power flapping flight at any given speed.
• Too large for flapping flight, so they soar
The shape and the location of its minimum (the Vmp) are similar for birds of similar geometry
• Ex. The cockatiel is more than half the mass if Budfeuor but, yet their flight and speed curve is
very similar.
Work loops have pattern with flight velocity similar to pattern of metabolic power output
• As birds go through periods of feed and fast their weight varies significantly. Flying with extra
mass has impact on the birds physiology.
• Significant increase in bird mass just before migration period
• Hummingbirds can sustainably lift substantial extra mass, they can maximize burst lift
• Mechanical power output increases as much as 40%
• When flying with extra mass metabolic rate increases by 60%
• Increase in power out means increase in wing beat frequency and stroke amplitude
• Hovering at higher elevations is much more costly; to sustain must have increases in wingbeat
frequency and stroke amplitude
• In experiment with Ruby-throated hummingbirds it has been found that hovering at high
amplitudes is sustained through greater spatial recruitment of motor units
• Higher wingbeat frequency in less dense air, due to less profile drag acting on wings
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Document Summary
Lecture 14: movement in fluid (air) iii part 1/2 of notes. Hummingbirds can aerobically power flight at many speeds, including hovering. Vulture: big bird, that cannot hover in place, they have low range of speed used for flapping flight, very narrow. California bird: very large bird, aerobic power cannot power flapping flight at any given speed, too large for flapping flight, so they soar. The shape and the location of its minimum (the vmp) are similar for birds of similar geometry: ex. The cockatiel is more than half the mass if budfeuor but, yet their flight and speed curve is very similar. Work loops have pattern with flight velocity similar to pattern of metabolic power output: as birds go through periods of feed and fast their weight varies significantly. Flying with extra mass has impact on the birds physiology. Increase in power out means increase in wing beat frequency and stroke amplitude frequency and stroke amplitude.
