Locomotion in Birds II On Land

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Locomotion in Birds IIOn Land
DeWildt Cheetah Research Center, S. Africa

• Some birds are flightless and depend entirely on
  walking, running, or swimming to get from place
  to place.
• Some birds spend most of their time on (Western
  Grebes 'running on the water') or in water
• Birds have special adaptations of the legs, feet,
  wings for terrestrial and aquatic (swimming and
  diving) locomotion.
• Walking, running, hopping, waddling - birds
  that travel along the ground regularly often have
  relatively long legs
• Among the ratites, such as Ostriches (ostrich
  video!) and Emus, there has been a reduction in
  the number of toes (less weight at end of the
  limb more efficient locomotion).

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Invisible, legless male ostrich on his nest
Mabula (Lodge Game Reserve), S. Africa
egg
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Running and walking

• http//www.youtube.com/watch?vTOMmyIQorAo
• Shorebirds moving with the waves to feed
• http//www.youtube.com/watch?v8hvAGO0kLHg
• Wood ducks and Mallards walking
• http//www.youtube.com/watch?voK51PAtZRDE
• Penguin waddling

http//people.eku.edu/ritchisong/554notes3.html
about 60 down page
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Waddling makes the most of short legs

• It may not be graceful, but the penguin's waddle
  makes perfect sense
• the side-to-side gait conserves energy
• University of California researchers found the
  gait works like a pendulum, with energy stored at
  the end of each swing for the next step
• "Our findings indicate that walking is expensive
  for penguins not because of waddling, but because
  they have such short legs that require their leg
  muscles to generate force very quickly ,"
  -Timothy Griffin, UC Berkeley
• Griffin and Kram (2000) decided to study penguins
  because they seem to be doing everything wrong.
  An earlier study showed penguins burning twice as
  many calories when walking as animals of similar
  size.
• the problem was the penguins' legs, not the
  side-to-side movements
• Emperor penguins were at least 3 feet tall but
  had legs only 10 inches long
• Penguins burn about the same amount of calories
  as animals with similar leg lengths
• The researchers coaxed penguins across a force
  platform with bits of fish
• They measured the side-to-side and fore-and-aft
  forces, as well as the vertical forces supporting
  their weight
• Walking speed of about 1.5 feet per second
• Percentage of energy retained during two steps is
  called the recovery rate
• Human recovery rate is about 65 percent
• The penguins had a recovery rate of up to 80
  percent.

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Avian head bobbing, stability

• Many birds move their heads forward through
  successive, fixed positions when walking. This
  head-bobbing behavior stabilizes visual fields,
  preventing blur
• Gaze stabilization could be for successful visual
  search, particularly for moving objects, but the
  time available varies with walking speed.
• No direct evidence that birds favor the
  stabilization phase while foraging either for
  moving or immobile food
• Cronin et al. (2005) head-bobbing behavior in
  foraging Whooping Cranes (Grus americana) as they
  searched for food they walk at speeds that allow
  the head to be immobilized at least 50 of the
  time
• The stable phase, unique to birds, contributes to
  visual stabilization
• Pigeons head-bob on landing, and herons stabilize
  heads when walking or when perch moves, almost
  certainly for visual function
• Head movements play essential roles giving
  visual cues, changing head angle, and fixating
  new objects

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Head movements in walking Whooping Cranes

• (A) One frame of a video of a walking crane,
  showing method of measurement of head, body, and
  leg position. The head is fit with a graphical
  model of the eye and bill, the body with a circle
  scaled to head and leg size and centered over the
  pelvis, and each lower leg with a line extending
  from ankle to foot (green, right leg red, left
  leg)
• (B) One sequence, at intervals of 33 ms, of a
  spontaneously foraging Whooping Crane through
  several stepping cycles
• average speed of about 0.46ms1
• head was stabilized throughout most of each
  foots step, with its positions at each of these
  times indicated by the arrows. (Watch a crane
  walk, click here! video by Thomas Cronin).

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Climbing
 
 

• Climbing - birds that climb, like woodpeckers,
  nuthatches, Black-and-white Warblers, and Pied
  Monarchs have sharply recurved claws to help grip
  the substrate (e.g., bark of a tree)
• http//people.eku.edu/ritchisong/554notes3.html
  (about 75 down)

White-breasted NuthatchSource
http//animalpicturesarchive.com/animal/APAsrch3.c
gi?qtnuthatch
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Flightless Birds
Galapagos Cormorant http//jon-atkinson.com/Large
20Images/La_Flightless_Cormorant.jpg
Dodo (Raphus cucullatus) from Mauritius

• All the ratites (ostrich, cassowaries)
• Members of groups living in predator-free locales
• Today grebes, pigeons, parrots, penguins,
  waterfowl, cormorants, auks, rails
• In the past Hawaiian Islands in the Pacific,
  Mascarene Islands in Indian Ocean geese, ibis,
  rails, parrots, dodo

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The dodo is a large flightless pigeon

• size of a small turkey
• lived only on the island of Mauritius in the
  Indian Ocean.
• No large predators anyway
• hungry sailors, non-native or alien animals
  dogs, cats and rats.
• The present model of the dodo by Phil Fraley
  Productions is currently the MOST accurate
  rendition

• Other than paintings and sketches dating back to
  the 1600s, we have no idea what real dodos look
  like.
• Many of the paintings were based on second- or
  third-hand information and so their accuracy is
  in doubt

http//rmbr.nus.edu.sg/news/images/
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Why become flightless?

• To fly you need
• Enlarged keel
• Calcification of sternum
• Large pectoralis muscle
• A lot of energy to maintain these, and to fly

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Why become flightless?

• No predators? Use the materials and energy for
  other purposes growth reproduction

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Why become flightless?

• For divers, reduced wings less trapped air
  less buoyancy easier swimming diving

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Birds that dont need to fly

• http//www.youtube.com/watch?vtlD9wLuJyMM
• They can steal from grocery stores
• Well, maybe they still need to fly to escape