Locomotion in Birds II On Land 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 waterWestern Grebes 'running on the 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).ostrich video! Emus DeWildt Cheetah Research Center, S. Africa

Invisible, legless male ostrich on his nest… egg Mabula (Lodge & Game Reserve), S. Africa

Running and walking Shorebirds moving with the waves to feed Wood ducks and Mallards walking Penguin waddling about 60% down page

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.

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

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 0.46ms –1 head was stabilized throughout most of each foot’s step, with its positions at each of these times indicated by the arrows. (Watch a crane walk, click here!; video by Thomas Cronin).click here

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) woodpeckers (about 75% down) White-breasted Nuthatch Source:

Flightless Birds 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 Galapagos Cormorant Dodo (Raphus cucullatus) from Mauritius

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

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

Why become flightless? No predators? Use the materials and energy for other purposes: growth & reproduction

Why become flightless? For divers, reduced wings = less trapped air & less buoyancy = easier swimming & diving

Birds that don’t need to fly… They can steal from grocery stores… Well, maybe they still need to fly to escape…