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Gallery - Bills, wings and Feet

[billpic1]Bills wings and feet

More information on these areas.


[More information about Bills]Bills

All Purpose and Specialist Bills

Gulls and Crows, natures scavengers, take a wide range of both animal and vegetable foods with their all purpose bills. But other birds, seeking to avoid competition within their preferred habitat, have become increasingly specialised feeders and depend on a fairly narrow selection of food.

If their methods of feeding differ, species which are otherwise alike in size may show striking differences in the design of their bills. Conversely, species which are unlike in other ways may have similar bills if they share the same feeding habits. The Kingfisher and the Heron, for example, feed by spearing fish, and have both evolved dagger-shaped bills.

The Rook, a specialised feeder on insects and earthworms, has a longer bill than its nearest relative the Carrion Crow which takes worms less often. Other soil feeders have taken this a step further, the Snipe, Curlew, Godwits, Woodcock and Dunlin which probe for food in soft mud have extremely long bills, each species avoids competition with others by probing at different depths.

All the Finches have the hard, conical bills typical of seed eaters, but the bill of each species is a little different to the rest. The most powerful, that of the Hawfinch can crack a cherry stone. At the other extreme, the thinner billed Goldfinch extracts the seeds of Teasels by boring for them.

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Here we see Seed Eaters, their bills are stout which is for cracking seeds.

The main group of birds is Sparrows, Buntings and Finches.

Although these birds mainly eat seeds they will eat fruit and insects.

The Crossbill is uniquely adapted for removing seeds from Pine, Spruce, Fir or Larch Cones, their almost exclusive diet.

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Bills that are thin and delicate are ideal for eating insects.

Many Warblers,Chats and specialist insect eaters such as Swallows, Swifts and Flycatchers will be in this group.

Many of these birds are migratory as much of there food supply disappears in the winter.

The remaining birds such as wrens survive on beetles and spiders in the winter.

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Bills that are made for tearing flesh are short and hooked.

Birds such as Hawks, Falcons, Eagles and Owls sit in this group.

Some of this group are specialist hunters such as the Osprey which eats fish but most take birds, mammals and carrion.

Birds such as the Hobby will also take large insects such as Dragonflies.

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Waders have various lengths of bills, the size will depend on their feeding habits.

The first group have short stubby bills for feeding on or near the surface looking for hydrobid snails, crabs or other invertebrates.

This group includes the small plovers, Turnstone and Sanderling.

These birds will often be seen on the waters edge chasing the tide looking for food.

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This group of waders have a longer and a straight bill.

With this size of bill, these birds are able to get at Shrimps, snails, worms and other invertebrates.

Often seen at the tides edge hunting their prey.

This group includes the Redshank, Greenshank and Snipe. A lot of these birds are also associated with freshwater pools and marshes.

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This group of waders have stout strong bills that have the length to get to prey deeper in the mud.

They feed on Shellfish, Molluscs, Crustaceans and Marine Worms.

While this group will be found on the tides edge, they do go on the deeper mud flats.

This group contains Curlew, Godwits, Oystercatchers and Whimbrels.

[bill19] [bill20] [bill21] Here are some birds with specially adapted bills.

The Avocet is unmistakable with its upcurved bill, used with a side to side sweeping motion in feeding on the mud flats.The Spoonbill with its aptly named bill also sweeps its bill from side to side as they filter the tiny creatures on which they feed. The Flamingo with its "Roman nose" has a specially adapted bill which sieves food from shallow water.

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Some birds that hunt for fish, amphibians and small mammals have a "Dagger" like bill.

This group of birds use both freshwater and sea habitats to hunt for their prey.This group include Heron, Egrets, Kingfisher, Gannet, Larger Grebes and Divers.

Some of these birds stand and wait for their prey to pass before they strike, others like the Gannet plunge dive from 25m to catch fish.

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Ducks that feed on the surface or by up-ending are called "Dabbling Ducks".You will also see these ducks eating vegetation on land. The Wigeon uses its short wide bill to crop grass and plants. Those that dive such as the Pochards are naturaly called "Diving Ducks". With the exception of the Shoveler there is very little difference in the bill.

Sea Ducks such as the Eider have a much stronger bill for dealing with mussels.

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[bill30] These birds are mainly fish eating and have specialist bills for the job.

Red Breasted Mergansers are part of a group often called "Sawbills".

The diet of a Pelican usually consists of fish, but they also eat amphibians, crustaceans and on some occasions, smaller birds. They often catch fish by expanding the throat pouch. Then they must drain the pouch above the surface before they can swallow.


[More information about Flight]Flight

Wing shape and flight

The shape of the wing is an important factor in determining the types of flight of which the bird is capable. Different shapes correspond to different trade-offs between beneficial characteristics, such as speed, low energy use, and manoeuvrability. The planform of the wing (the shape of the wing as seen from below)[bflight2] can be described in terms of two parameters, aspect ratio and wing loading. Aspect ratio is the ratio of wingspan to the mean of its chord (or the square of the wingspan divided by wing area). Wing loading is the ratio of weight to wing area.

Most kinds of bird wings can be grouped into four types, with some falling between two of these types. These types of wings are elliptical wings, high speed wings, high aspect ratio wings and soaring wings with slots.

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Elliptical wings

Elliptical wings are short and rounded, having a low aspect ratio, allowing for tight manoeuvring in confined spaces such as might be found in dense vegetation. As such they are common in forest raptors such as Goshawks and Sparrowhawks, and many passerines.

They are also common in species that use a rapid take off to evade predators, such as pheasants and partridges.

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High speed wings

High speed wings are short, pointed wings that when combined with a heavy wing loading and rapid wing beats provide an energetically expensive high speed. This type of flight is used by the bird with the fastest wing speed, the peregrine falcon, as well as by most of the ducks. The same wing shape is used by the auks for a different purpose; auks use their wings to "fly" underwater. The Peregrine Falcon has the highest recorded dive speed of 175 mph (282 km/h). The fastest straight, powered flight is the Spine-tailed Swift at 105 mph (170 km/h).

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High aspect ratio wings

The Tern uses its low wing loading and high aspect ratio to achieve low speed flight, important for a species that plunge dives for fish

High aspect ratio wings, which usually have low wing loading and are far longer than they are wide, are used for slower flight, almost hovering (as used by kestrels, terns and nightjars) or alternatively by birds that specialize in soaring and gliding flight, particularly that used by seabirds, dynamic soaring, which use different wind speeds at different heights (wind shear) above the waves in the ocean to provide lift.

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Soaring wings with deep slots

These are the wings favoured by the larger species of inland birds, such as eagles, vultures, pelicans, and storks. The slots at the end of the wings, between the primaries, reduce the induced drag at the tips, whilst the shorter size of the wings aids in takeoff (high aspect ratio wings require a long taxi in order to get airborne).

Hovering

[bflight1] Hovering is used by several species of birds (and specialized in by one family). True hovering, which is generating lift through flapping alone rather than as a product of the bird's passage through the air, demands a lot of energy. This means that it is confined to smaller birds; the largest bird able to truly hover is the pied kingfisher, although larger birds can hover for short periods of time. Larger birds that hover for prolonged periods do so by flying into a headwind, allowing them to remain stationary relative to the ground (or water). Kestrels, terns and even hawks use this wind hovering.

The ruby-throated Hummingbird can beat its wings 52 times a second

Most birds that hover have high aspect ratio wings that are suited to low speed flying. One major exception to this is the hummingbirds, which are the most accomplished hoverers of all the birds. Hummingbird flight is different from other bird flight in that the wing is extended throughout the whole stroke, the stroke being a symmetrical figure of eight, with the wing producing lift on both the up- and down-stroke. Some hummingbirds can beat their wings 52 times a second, though others do so less frequently.

Take-off and landing

[bflight8] Take-off is one of the most energetically demanding aspects of flight, as the bird needs to generate enough airflow across the wing to create lift. With small birds a jump up will suffice, while for larger birds this is not possible. In this situation, birds need to take a run up in order to generate the airflow to take off. Large birds take off by facing into the wind, or, if they can, by perching on a branch or cliff so that all they need to do is drop off into the air.

[bflight3] Landing is also a problem for large birds with high wing loadings. This problem is dealt with in some species by aiming for a point below the intended landing area (such as a nest on a cliff) then pulling up beforehand. If timed correctly, the airspeed once the target is reached is virtually nil. Landing on water is simpler, and the larger waterfowl species prefer to do so whenever possible, landing into wind and using their feet as skids. In order to lose height rapidly prior to landing, some large birds such as geese indulge in a rapid alternating series of sideslips in a manoeuvre termed as whiffling

Technical parts of this write up on flight was taken from an article on Wikipedia and if I could find a name I would thank them ;o)


Feet

[bfeet1] SONG BIRDS or PERCHING BIRDS (warblers, thrushes, wrens, etc.) have independent, flexible toes, with one pointing backwards, ideal for grasping perches.

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Why don't perching birds fall out of trees when they sleep? When perching birds sit, a tendon on the backside of the ankle automatically flexes locking their toes around the branch. With feet locked, sleeping birds don't fall. As the bird stands up its feet release

[bfeet3]WOODPECKERS have two toes pointing forwards and two backwards; for climbing up, down, and sideways on tree trunks

[bfeet5] WATER BIRDS such as ducks have webbing between their toes for swimming. GULLS also have feet similar to these so they don't sink while walking in the soft sand or mud near the water's edge.

[bfeet4] The long toes of birds such as Herons, Coots and Moorhens which spreads the bird's weight over a large surface area, facilitates walking on soft surfaces near the water's edge (where wading birds like to eat).

[bfeet6] RAPTORS such as hawks, eagles, and owls use large claws (called talons) to capture, kill, and carry prey with their feet.

Pheasants and chickens use their strong feet to scratch the dirt and leaf litter to uncover seeds and insects.

Strong-legged flightless birds, like the cassowary, protect themselves by kicking with their powerful feet and sharp claws



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