The Evolutionary Adaptations of Hummingbirds

1
The Evolutionary Adaptations of Hummingbirds

• Nicole Eastep, Garrett Edwards, Daniel Ngembus
  Rachel Travitz

2

• Hummingbirds are thought to have a long history,
  but it is hard to determine their exact lineage.
• Linnaeus
• Buffon

3

• 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.

4

• Hummingbirds are the overachievers of the avian
  world.
• To sustain their hyperactive lifestyle, they eat
  their own bodyweight in nectar and insects every
  day.

5
Does wing pace of hummingbirds have an advantage
on the overall fitness of the heart?
FEMALES
6
Hummingbirds 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

7
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.

8
Torpor

• Is a mechanism used to preserve energy through a
  reduction in metabolic rate.
• What this suggests

9
Torpor Contiued

• Studies show that a portion of the energy
  consumed during feeding is stored.

10
(No Transcript)
11

• When torpor does occur, it drastically lowers the
  rate of depletion of remaining energy reserves.

12

• 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.

13
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.

14
Was diet or rapid wing movement developed first
in hummingbirds?
MALES
15
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 wasnt a perch available to
  utilize while feeding.

16

• 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.

17
(No Transcript)
18

• Results
• Even the smallest of hummingbirds prefer to perch
  while feeding if given the opportunity.
• What This Means

19

• 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.

20

• 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.

21
Two Extreme Forms of Flight

• Hovering and low-speed flight (figure 8 movement)
• Fast forward flight (oval movement)

22

• http//dsc.discovery.com/videos/time-warp-hummingb
  ird-in-high-speed.html

23
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.

24
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.

25
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, p722-726.
• Chambers, Lanny. About Hummingbirds.
  Hummingbirds.net. 2009. http//www.hummingbirds.n
  et/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-about-the-hum
  mingbirds.html