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The different bills’shapes - Page 2

Show me your bill, I will know what you eat!

Introduction

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Aquatic birds such as Anatidae, (ducks, geese, swans and others) have peculiar bill with lamellae on the edges of the mandibles.
Many ducks feed on vegetation on the shore or dabble into the soft mud to search for seeds or aquatic plants. These species can filter the mud through the lamellae, in order to keep only the food items.

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Text by Nicole Bouglouan

Sources:

L’ENCYCLOPEDIE MONDIALE DES OISEAUX - Dr Christopher M. Perrins -  BORDAS - ISBN: 2040185607

 

See the article: Description of the bird and its plumage

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Cinnamon Teal

Anas cyanoptera

Red-crested Pochard

Netta rufina

Geese often feed in drier areas, and the strong bill with cutting edges allow them to cut the grass when they are grazing on the ground.

Greater White-fronted Goose

Anser albifrons

Greylag Goose

Anser anser

On the other hand, the mergansers have narrow, serrated bill, making easy for them to catch small fish.
They usually are more rapid and active than other ducks’ species.

Goosander

Mergus merganser

Hooded Merganser

Lophodytes cucullatus

Aquatic birds such as Ardeidae (herons, egrets, bitterns and night herons) have long, straight, dagger-shaped bill. These birds feed on fish, molluscs and other vertebrates and invertebrates, both aquatic and terrestrial, including small rodents.

Tricoloured Heron

Egretta tricolor

Black-crowned Night Heron

Nycticorax nycticorax

Grey Heron

Ardea cinerea

American Bittern

Botaurus lentiginosus

The prey is jabbed with the bill while the bird walks slowly at water edge or waits motionless for a prey passing by. 

© Nicole Bouglouan

Western Great Egret

Egretta alba

Little Egret

Egretta garzetta

But other birds’ species have such bill. Storks also have long, straight, pointed bill. They quickly catch the prey with the bill, but usually, they do not jab it.   

Black Stork

Ciconia nigra

White Stork

Ciconia ciconia

Cranes have a long, straight bill too, and use it rather than the storks. They catch the prey with the bill tip. They also dig into the soil in order to extract seeds and invertebrates. They probe in the same way in the wet areas to feed on roots and stems of aquatic plants.    

Common Crane

Grus grus

Sandhill Crane

Grus canadensis

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Other aquatic birds have almost the same feeding behaviour, but the bill is different. Ibises have long, curved bill, allowing them to probe into the mud or the soil for food.
To feed, they walk slowly in shallow water while foraging. They sweep their bill from side to side, and probe at the bottom, to find aquatic invertebrates. They also forage on mud or short grass, finding prey by touch, while probing, or by sight.

American White Ibis

Eudocimus albus

Sacred Ibis

Threskiornis aethiopica

The species living in dry areas perform the same behaviour but into cracks and fissures in the earth.

But the strangest bill belongs to the spoonbills. The bill is spatula-shaped, with flat, broad and rounded tip, and well adapted to their feeding behaviour.
They fish "with the touch", while walking slowly, with the bill constantly immersed, performing long half circles from side to side, sweeping the fishing area to capture preys.

Roseate Spoonbill

Ajaia ajaja

Eurasian Spoonbill

Platalea leucorodia

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We have to mention the very well adapted bill of the Asian Openbill and the African Openbill. Both have an open bill formed by a hollow in the lower mandible. Both mandibles meet at tip.
These birds feed on large aquatic snails which live in wet areas. The prey is located by touch and sight. The gap in the bill allows good grasp of the snail’s shell.
Openbills walk slowly in shallow water, searching for prey. They extract the snail from the shell with the pointed lower mandible.

Asian Openbill

Anastomus oscitans

African Openbill

Anastomus lamelligerus

This amazing bird will be the conclusion of this page.
The Shoebill has stunning bill of up 21 cm length, and 10 cm width. It is a huge structure, with sharp curved hook at tip. Very sharp edges in mandibles allow capturing and cutting up prey before swallowing it.

Shoebill

Balaeniceps rex

One more time, each shape is very well adapted to the behaviour of the bird. Only looking at the bill, we can know what its favourite food is, and how it can get it!

Another stunning bill is that of flamingos.
The bill is adapted for its unique feeding method: it is held upside down in the water, and swept back and forth, in order to filter out the tiny organisms.
The bill is bent sharply downward with filtering structure. The upper jaw fits into the lower jaw like a box lid. The fleshy tongue works to and fro like a piston. The tongue is covered with bristles like projections that help to filter water, mud and food particles through the lamellae.

Caribbean Flamingo

Phoenicopterus ruber ruber

Pelicans show different behaviour while feeding.
The bill has a distensible gular pouch on the lower mandible. The pelicans plunge their bill into the water, in order to fill up the gular pouch, and then, they filter the water with semi open bills, and swallow the fish head first.

American White pelican

Pelecanus erythrorhynchos

Australian pelican

Pelecanus conspicillatus

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Only one member in the Family of Scopidae, the Hamerkop has long, heavy bill. It is deep and laterally compressed. Culmen is ridged and ends in slight hook at tip.
The bird uses the thinner lower mandible to cut up prey or vegetation, or any food item.
This peculiar bill is a response to the bird’s feeding requirements.

Hamerkop

Scopus umbretta

Boatbill

Cochlearius cochlearius

The Boatbill has remarkably broad and heavy bill, of about 7, 5 cm long and 5 cm wide.
This large broad bill is used as a spoon, to catch motionless preys. It seems to be very sensitive, and it opens at the merest touch.