The document discusses the many variations in beak shape and size found in birds, which relate to their different feeding behaviors and diets. It describes the specialized beaks of seed-eating birds like finches, fruit-eating parrots, insect-eating flycatchers, wood-chiseling beaks of woodpeckers, long probing beaks of shorebirds, and fish-catching beaks of kingfishers. Unique modifications are also seen in a few species, like the curved beak of the wry-billed plover or scissor-like beak of the black skimmer.

1. Modifications Of Beaks in Birds.

2. • Modern birds are without teeth.
• Jaws are covered with horny sheath called
rhamphotheca.
• Beak at once plays the role of mouth and hand.
• Diverse role in normal functions .

3. Shape and Size of Beak :
• Shape and size of the beak vary in birds with
different feeding habits.
May be short or long
Broad or narrow
Blunt ended or pointed
Curved downward or upward
Brightly colored.

4. According to shape,size and structure of the beak the most
important modifications are described here.
Seed-eating Beaks:
Short , peg-like and conical beaks found in seed-eating (
graminivorous ) birds .e.g.
Sparrows, finches,Cardinals,etc

5. • Larks have small and weak beak used for picking up the
small seed which are swallowed whole or crushed.
• In crossbills the beak is sharply pointed and hooked tips
of the jaws in cross each other.
• Jaws overlap each other.
• Such beak enables bird to obtain seeds that are deeply
buried.

6. Cutting Beaks:
• Long , slender and with cutting edges .
• Found in crows and ravens .

7. Fruit-eating Beaks:
• Beak is sharp , massive , deeply hooked and
extremely strong .
• Well adaptated for gnawing or breaking open hard
seeds and nuts.
• Found in parrots , cockatoos , macaws , toucans
and hornbills.
• Parrots can freely move their upper jaw.

8. • Macaws can crush palm nuts and
shell which are so hard as to be
difficult to beak with hammer.
• Toucans long beak collect the
fruit from slender twigs that can't
support the weight of bird .

9. • Hornbills have light beak which enables the bird to
produce exceptionally loud cry.

10. Insectivorous Beaks:
• Found in Swift's , swallows , flycatchers and Night-
jars.
• Show less variety in shape and of the bill.
• All these birds capture small insects in mid-air
rushing along a great speed.
• In Swallows and Swift's the beak is small, wide and
delicate.

11. In flycatchers ( kingbirds ) , it is short, strong and greatly
depressed.Kingbirds snap up the insects in the air with a
loud click of the bill.
In fish-eating birds like kingfisher, it is long and pointed.

12. Wood-chiselling Beaks:
• Found in woodpeckers.
• Beak is elongated, straright, narrow and stout chisel-like
• These types of beaks are used for drumming or drilling
into wood for insect larvae or for nest construction.

13. Mud-probing Beaks:
• Beak is extremely long and slender and used as
probe for thrusting far down into water & mud in
search of worms and larvae.
• Found in avocet, curlew, whimbrel, snipe's,
sandpiper, stilt,jacana, woodcock's and lapwing.
• The beak of avocet curves upward.The beak skims
the water to collect the insects larvae and other
small creatures.

14. • Curlew and whimbrel have lond downwardly curved beak,
which are used as foreceps to drag out small crustaceans,
molluscs, and so on, from their hiding places.

15. • In snipe's and woodcock's the beak is highly specialized
with a flexible tip on the upper beak which is richly
supplied with nerves ending in small pits .
• Only the jaw tips are opened sufficiently wide to allow
capture of worm

16. Tearing and piercing Beaks:
• The beak is short, pointed, sharped edged, powerful,
hooked and operated by well-developed mandibular
muscles.
• Found in carrion-feeding and flesh-eating birds like
vultures, hawks, eagles, owl's, shrikes etc .

17. • Falcons and other birds of prey have their upper beaks
cut into teeth, helpful in tearing food.

18. Water and mud straining Beaks:
• The beak is broad and flat .
• Found in ducks, teals, geese and shovellers.
• Such beaks enables bird to avail itself rich store of food
in the shape of insects and others organisms which
teem in water.

19. • In flamingo's the long-legged and long-necked bird wades in
shallow water and obtain food by sifting mud of the
bottom.
• In doing so the beak is brought down in an inverted
position, parallel to the mud surface, forming the most
efficient scoop.

20. Fish-gripping Beaks :
• The beak is long and narrow, the edges of which armed
with sharp, backwardly-directed, tooth-like adapted for
capture of fish .
• Found in cormorants, mergansers, wood-ducks , darters,
kingfisher and storks.

21. • Storks, herons and Kingfishers possess long, powerful
and sharply-pointed spearing beaks to capture fish, frogs,
tadpoles, crustaceans, molluscs and similar other small
aquatic animals.

22. Flower-probing Beaks:
• The beak is long, pointed,rapier-like and probing.
• Found in humming bird, hermit and swordbill.
• Humming bird dive down the corollas of flowers for
sucking honey and insects.
• They suspend themselves in air
before flower, while they
extract their honey and
insects.

23. Other Modifications of Beaks:
• The modification of beaks described so far are
characteristics of large number of species.
• But several kinds of unique modifications are met with
only in a single species or in three to four.

24. • In the little wry-billed Plover ( Anarhynchus frontalis ) of
the New zealand, the beak is drawn out to a fine point and
curves sharply to right.
• It is admirably suited for extracting and picking up small
crustaceans and small prey lurking beneath the edges of
stones.

25. • In scissor-bill or Black Skimmer ( Rhyndrops nigra ) , the
jaws are distally compressed sideways like the blade of a
knife.
• Lower jaw is much longer than upper so the beak looks as
if it is were broken.
• The bird feeds entirely on the small fishes swimming at
the top of water.

26. • The extinct Huias or Parson-birds of New Zealand were
remarkable, as the two sexes possessed different kinds
of beaks ( dimorphism ).
• Male had short, sharp and slightly curved beak for
tunneling into dead wood for grubs
• Female beak was twice as long and much decurved for
extracting prey where male could not reach.

27. • The New Zealand Kiwi ( Apteryx ) is remarkable for
being the only bird that bears nostrils at the extremity
of the beak.