Transcript The Evolutionary Adaptations of Hummingbirds

The Evolutionary Adaptations of
Hummingbirds
Nicole Eastep, Garrett Edwards,
Daniel Ngembus & Rachel Travitz
•Hummingbirds are thought to have a long
history, but it is hard to determine their exact
lineage.
•Linnaeus
•Buffon
• Hummingbirds eat every 15 to 20 minutes to
maintain energy levels.
• When they are unable to feed due to weather
or other reasons, they go into torpor.
• Hummingbirds are the overachievers of the
avian world.
• To sustain their hyperactive lifestyle, they eat
their own bodyweight in nectar and insects
every day.
Does wing pace of hummingbirds
have an advantage on the overall
fitness of the heart?
FEMALES
Hummingbird’s Heart
• Fairly large organ when compared to the small
body and low weight of the bird.
• Depending on the species:
• Compared to its own body size:
Heartbeat
•During flight:
•A rate of 1260 beats per minute has been recorded.
•During torpor:
•The heart rate can drop to 50-180 per minute.
Torpor
• Is a mechanism used to preserve energy
through a reduction in metabolic rate.
• What this suggests:
Torpor Contiued
• Studies show that a portion of the energy
consumed during feeding is stored.
• When torpor does occur, it drastically lowers
the rate of depletion of remaining energy
reserves.
• Hovering demands an extensive amount of
energy.
• While hovering, oxygen intake, fuel supply and
waste removal in hummingbirds are all
increased.
• This is the highest energy expenditure out of
all vertebrates.
How this relates to our Question
• Hummingbirds have a higher wing pace
compared to other birds which indicates a higher
overall fitness of the heart and the muscle of the
bird in general.
• The wing pace of hummingbirds indicates an
overall fitness on the heart and body. It is not
simply a reflection of having a small body size.
Was diet or rapid wing movement
developed first in hummingbirds?
MALES
Case Study
• Richard S. Miller (1985) performed a study on
why hummingbirds hover while feeding from
flowers.
• He wanted to know whether or not these
birds actually preferred to hover or if they
only hovered because there wasn’t a perch
available to utilize while feeding.
• Implication:
– The relative importance of energy costs versus
speed increases with relative body size.
• Birds that hover while feeding can move
quicker from flower to flower than birds that
perch.
• So, hovering is not necessarily preferred by
hummingbirds.
• Results:
– Even the smallest of hummingbirds prefer to
perch while feeding if given the opportunity.
• What This Means
• Hovering is most likely the dominant feeding
mode for Hummingbirds
• Some plants have even evolved flowers that tend
to exclude bees and attract hummingbirds
• This suggests that plants, not pollinators, are
responsible for this coevolved system
• The fact that hoverers can move more quickly
between flowers may be more beneficial to the
plants than the birds, forcing a cost on the birds
that is less optimal.
• Bird pollination seems to be more beneficial
to plants for multiple reasons:
• To Summarize:
• Hovering is not necessarily a preferred mode of
feeding, but one that cant be avoided.
Two Extreme Forms of Flight
• Hovering and low-speed flight (figure 8
movement)
• Fast forward flight (oval movement)
• http://dsc.discovery.com/videos/time-warphummingbird-in-high-speed.html
How this relates to our Question
• The rapid wing movements(hovering or perching)
of Hummingbirds depends on the architecture of
the plants(diet).
• The Diet or structure of the flowers/plants forced
the hummingbirds to adjust the necessary rapid
wing movements which provided a better chance
to obtain the maximum amount of food.
Other interesting facts
• There are seventeen species of hummingbirds in North America.
• They have tiny little feet that are only good for perching, scratching or
preening. This means if they wish to move, even a few inches, they must
fly.
• Hummers can starve to death in about an hour.
• They eat every 10 minutes throughout the day.
• Have very good memories and will even be able to remember where they
found food from the previous year.
• Can fly up to 25-30 mph.
• The only bird that has an insect that will eat it. Praying mantis's think they
are yummy.
• Average lifespan is 3-6years. The record is 12 years.
• They lay two eggs that are about ½ inch long.
• The eggs hatch in 13-22 days depending on the species.
Sources
•
•
•
•
•
•
•
Flight of the Hummingbird, Earthwatch Institute Journal, Jun/Jul2003, Vol. 22 Issue 2, p35,
1/2p.
Chai, Peng and Robert Dudley. Maximum Flight Performance of Hummingbirds: Capacities,
Constraints, and Trade-Offs. The American Naturalist, Vol. 153, Vo. 102, p398-4111
Miller, Richard S. Why Hummingbirds Hover? The Auk, October 1985, Vol. 102 No 4, p722726.
Chambers, Lanny. About Hummingbirds. Hummingbirds.net. 2009.
http://www.hummingbirds.net/about.html
Hainsworth, F. Reed, Brian G. Collins, and Larry L. Wolf. The Function of Torpor in
Hummingbirds. Physiological Zoology. July 1977. Vol. 50. No 3. P. 215-222
Hummingbird Anatomy. World of Hummingbirds. 2010.
Gupta, Rachna. Facts About Hummingbirds. http://www.buzzle.com/articles/facts-aboutthe-hummingbirds.html