Variation and Selection.

Name: Sarah Azzopardi Class: 5 Diamond

Migratory Birds of the Maltese Islands. The Birds recorded in Malta contains a total of 392 species. Malta has a limited range of breeding birds with only 21 regular breeders and about 17 occasional breeders. Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat, or weather. In this project I shall be concentrating on a limited number of migratory birds of the Maltese Islands while making a simple analysis of their variations and adaptations. This is part of my eTwinning project "Migratory Birds Across Europe" that we are doing with Spain, Greece, Italy and Poland. I shall be analysing the variations of these birds as part of the topic "Variations and Selections" that we are studying in form 5 Biology. Therefore I shall refer a bit to Charles Darwin's Voyage of the Beagle and his analysis about some birds particularly the finches.

Darwin's finches (also known as the Galápagos finches) are a group of about 15 species of passerine birds. It is still not clear which bird family they belong to, but they are not related to the true finches. They were first collected by Charles Darwin on the Galápagos Islands during “The Voyage of the Beagle”. Despite the fact that they intrigued Darwin, they are far too complex a group of animals for Darwin to have understood. Nevertheless, they played an important role in helping him recognize the reality of the evolutionary process. The name was first applied in 1936, by the ornithologist David Lack, who published the first modern ecological and evolutionary study of the finches. The birds vary in size from 10 to 20 cm and weigh between 8 and 38 grams. The most important differences between species are in the size and shape of their beaks, and the beaks are highly adapted to different food sources. Today Darwin's finches are the subject of intense study, and they are revealing much about the evolutionary process.

Variations in Maltese Birds. The status is listed as common or regular it doesn't necessarily mean that it may be seen all year round, but in most cases it means that it’s common during migration. The birds I will be focusing on are:

Biological name: English name: Maltese name: Status:

Hydrobates pelagicus Mediterranean Storm Petrel Kangu ta' Filfla Common, Regular breeder

Pernis apivorus Honey Buzzard Kuċċarda Common Migrant

Calidris alpina Dunlin Beggazzina tad-Dabra Common

Larus michahellis Yellow-legged Gull Gawwija Prima Common Winter visitor

Philomachus pugnax Ruff Girwiel Common

Streptopelia turtur Turtle Dove Gamiema Common migrant

Alauda arvensis Sky Lark Alwetta Common

Oriolus Oriolus Golden Oriole Tajra Safra Regular

1. MEDITERRANEAN STORM PETREL

Order: Procellariiformes Family: Hydrobatidae The storm petrel is a small, black sea-bird with a white rump. Its webbed-feet and beak are black as well. This species, like many other Petrel Species, approaches land only during its breeding season at night. It spends most of its life feeding on aquatic animals, plants and small fish out at sea. Its breeding season starts in late March when it starts to get closer to land; it lays a single egg in May/June in a crack or hole in rocks. The young fledges in July/August and it immediately abandons the colony and ventures out at sea. The Storm Petrel is very localized in the Maltese

Islands, breeding only in 2 localities; large colony on the island of Filfla and a smaller colony at Ta' Ċenċ.

2. HONEY BUZZARD

Order: Falconiformes

Family: Accipitridae The Honey Buzzard migrates in flocks and is usually seen in the afternoons occasionally roost in wooded areas and other undisturbed land. They spend their winter in Africa south of the Sahara. The structure of a big long winged buzzard is with a small head and a rather long tail with three dark bands. It has variable plumage patterns. Like many other birds of prey, the honey buzzard finds it difficult to fly over open sea difficult so they prefer to soar on rising air which occurs on land therefore their migratory routes concentrate over short sea crossings like Gibraltar, Sicily,

Sweden, Greece, Turkey and Malta. It likes eating Honey, wasps, bees, ants and other insects. Honey Buzzard doesn’t breed in Malta.

3. DUNLIN

Order: Charadriiformes

Family: Scolopacidae The Dunlin is a medium-sized wader. It has brownish upper sides and white undersides. It has a long, slightly curved black bill. Breeds on the ground where it lays 4 eggs. As other waders, it typically feeds by searching for insects and worms in mud near the water edge, often feeds alongside other wader species. Breeds in northern European countries and most birds winter in North Africa. Regular migrant which is recorded in almost all months of the year.

3. YELLOW-LEGGED GULL Order: Charadriiformes Family: Laridae The Yellow-legged Gull is a large gull with yellow legs a grey back, white-headed in autumn, and have black wing tips with few white spots. They have a red spot on the bill as adults and a red ring around the eye. These are omnivores like most Larus gulls, and they will scavenge on rubbish tips and elsewhere, as well as seeking suitable small prey in fields or on the coast, or robbing other birds of their catches. Yellow-legged Gulls usually breed in colonies. Eggs, usually 3, are laid from mid-March to early May and are defended vigorously by this large gull. The Yellow-legged Gull is the largest breeding bird of Malta. Seen mainly at sea from the coast.

4. RUFF

Order: Charadriiformes Family: Scolopacidae The Ruff is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia. This highly gregarious sandpiper is migratory and sometimes forms huge flocks in its winter grounds. The male is much larger than the female, and has a breeding plumage that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers. The female and the non-breeding male have grey-brown upper parts and mainly white under parts. The name Ruff is derived from the ruff, an exaggerated collar fashionable from the mid-sixteenth century to the mid-seventeenth century.

5. TURTLE DOVE

Order: Columbiformes Family: Columbidae The Turtle Dove is a medium-sized dove. Have orange-brown feathers on wing, pinkish chest, striped patch on neck and grayish head. In Europe it breeds in open low land, woods and agricultural areas. It nests in trees. It breeds in all of Europe except in the far north. In autumn, migrates to south of the Sahara and return passage in spring. The overall European population has declined in recent decades mainly due to agricultural changes, development and as it is also heavily hunted on passage through the Mediterranean countries. Turtle Dove diet consists of seed, fruit and even small insects.

6. SKY LARK

Order: Passeriformes Family: Alaudidae It has brown sandy plumage with dark stripes on back. It has a blunt brown black crest and a pale whitish stripe on eye, buff breast and whitish belly. It also has a long hind claw too. It forages the ground in grass or bare soil, eating seeds, shoots and insects. The Skylark is a social bird and it's normally seen in flocks flying and also feeding together. It builds it's nest on the ground laying 3 to 5 eggs, having 2-3 broods. Although widespread, unfortunately the Skylark overall population has declined in recent years mainly due to intensive modern agricultural practices.

7. GOLDEN ORIOLE

Order: Passeriformes Family: Oriolidae The Golden Oriole is an exotic looking bird, with its striking yellow and black plumage. It feeds on caterpillars, insects, fruits and berries. The Male has the sensational plumage while the Female is more dull. It is often seen resting on trees occasionally in small groups. It has a pleasant, whistling song. Prefers wooded areas with cover and forage. Many Orioles winter in Africa and then all come back to their breeding grounds in Europe. It makes its nest in a tree with 3-4 eggs laid. Golden Orioles live up to 5 years and their population is secure.

0

10

20

30

40

50

60

Avreage Size of bird(cm)

Avreage Size of bird(cm)

Variations.

1. Size of bird. Biological name: English name: Approximate size of bird:

Hydrobates pelagicus Mediterranean Storm Petrel 15–16 cm

Pernis apivorus Honey Buzzard 52 - 60 cm

Calidris alpina Dunlin 16 - 22 cm

Larus michahellis Yellow-legged Gull 50 cm

Philomachus pugnax Ruff 29–32 cm

Streptopelia turtur Turtle Dove 26-28 cm

Alauda arvensis Sky Lark 15 - 20 cm

Oriolus Oriolus Golden Oriole 20 - 30 cm

This table results that there is a range of different size of birds from 15cm to 60cm. The smaller birds can fly with ease, build small nests, and look for small sized foods in different places like soil, bark of trees, holes, between rubble walls etc. The larger birds seek food in larger places. They also need larger or more abundant food.Usually the female can also be distinguished from the male by its slightly smaller size.

2. Colour of birds.

English Name: Colour of Bird: Picture:

Mediterranean Storm Petrel

Very dark brown all over with a white patch on his tail.So from the upper parts it would be very good to camouflage whilst flying over the waters, however it can open its wings and stay straight to expose its underparts and be conspicuous either to attract attention or to frighten away any predators.

Honey Buzzard

A big long winged buzzard with a small head and a rather long tail with three dark bands. It has variable plumage patterns. The male has a grey head, Female has a brownish head and juvenile has a much whitish head with a yellow base at the bill. These colours permit hiding by camouflage in trees, fields, countryside.

Dunlin

It has brownish upper sides and white undersides. It has a long, slightly curved black bill. In summer, adults have a fine dark black patch on its whitish breast.Very good to hide by camouflaging in the countryside colours.

Yellow-legged Gull

Adults have darker grey backs and wings than herring gulls, but are paler than lesser black-backed gulls. They have more black in the wing tips than herring gulls.The legs are bright yellow, there is a red ring around the eye and the bill is yellow with a large red

spot. This bird has a

conspicuous colour that doesn’t permit much hiding by camouflage in fields or countryside

Ruff

The Ruff is a long-necked, pot-bellied bird.The male is much larger than the female (the reeve), and has a

breeding plumage that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers that inspired this bird's English name. The female and the non-breeding male have grey-brown upperparts and mainly white underparts.

Turtle Dove

Turtle Dove may be recognised by its browner colour, and the black-and-white-striped patch on the side of its neck. The tail is notable as the bird flies from the observer; it is wedge shaped, with a dark centre and white borders and tips.Very good to hide by camouflaging in the countryside colours.

Sky Lark

The sexes are alike and the birds are streaky brown on the back and buff-white below with dark-brown streaking on the upper breast. The tail is brown with outer-tail feathers of white. There is a small up-turned crest on the back of the head, visible only when raised.

Golden Oriole

On the male, this

beautiful golden colour

contrasts starkly with the

largely black wings and

tail, and the black streak

that extends through

each red eye. Their small

size and camouflage-like

coloring usually make

them difficult to see in the

dappled light of the tree

canopies in which they

live.

3. Size of Leg

English Name: Size of leg: Variations:

Mediterranean Storm Petrel

5cm Its feet are adapted for paddling in water.

Honey Buzzard 10cm Its short firm “digging” legs are

capable of digging for ground wasp nests.

Dunlin 5cm Its thin feet are adapted to walk

through the coastline.

Yellow-legged Gull 15cm Strong yellow feet to grab and

firmly catch the prey while flying over water.

Ruff 8cm Thin legs easy to probe in the

mud to find it’s food.

Turtle Dove 3cm

Small feet used for perching in trees and almost on all other terrain even wire.

Sky Lark

4cm It has sturdy legs and spends much time on the ground foraging for seeds, supplemented with insects in the breeding season.

Golden Oriole 8cm Feet that enable him to move

quickly through branches and on ground.

From this data ,we can see that mostly feet are used to catch their prey with one foot or both, depending on the size of the victim. The foot, it is able to change this configuration for better catch.

Beak Length

Short

Medium

Long

4. Structure of Beak.

English Name: Beak Structure:

Mediterranean Storm Petrel Its beak is around 2cm long and very narrow and pointed to be able to grab small insects and worms from holes and crevices. (medium)

Honey Buzzard Short curved pointed beak that enables it to grasp and tear the flesh from its prey such as mice, small mammals and reptiles.

Dunlin Dunlins long beaks are a little longer than their heads, and curve downwards slightly as it pokes into the ground when it probes for food.

Yellow-legged Gull

They have a thick bill with a sharply curved culmen, creating a blunt tipped bill. They sweep their bill from side to side, and probe at the bottom, to find aquatic invertebrates.(medium)

Ruff Ruff while walking through the meadows they feed by boring their long bill into the wet ground for worms, pecking on the ground for insects.

Turtle Dove Short narrow beak that is suitable for feeding on seeds.

Sky Lark

Thin,short bill with pointed tip. This shape allows them to feed numerous food items such as insects,earthworms and seeds, according to the season.

Golden Oriole

Golden oriole’s sharp, stout bill is highly effective at plucking insects or berries from vegetation, as well as tearing flesh off

small vertebrate prey. (medium)

5. Type of Feathers.

English Name: Type of Feathers:

Mediterranean Storm Petrel Short dark feathers cover its main body, but longer feathers cover the forearms that enable very efficient flight and gliding over the waters.

Honey Buzzard

It has 3 phases of feather change and colour during its life time. Long feathers on the wings that enable it to exploit the air currants to be able to hoover and glide.

Dunlin

The short, warm grey feathers as opposed to the cold grey and which in some light conditions is almost brown so it makes it very good at camouflaging with the surroundings.

Yellow-legged Gull Short feathers cover the main body, with longer feathers at the wing enables it to make use of atmospheric updrafts by soaring.

Ruff

Ruff in breeding plumage each with prominent neck feathers to increase insulation while flying in cold weathers. Short feathers on the body but longer feathers on the wings.

Turtle Dove

Fine feathers on its main body. The feathers on the upperside are bigger and more colourful than the underside. The ones on the wings are taller for flight.

Sky Lark In flight, they display a short tail and short broad wings. The tail and the rear edge of the wings are edged longer with white.

Golden Oriole Short narrow feathers cover the main body and longer feathers to cover the wings.The wings are good for flight.

Conclusion: In this project I have researched about the 5 different variations of birds in Malta.I also analyzed data from focal studies to understand changes in bird populations in response to factors such as weather, predation, competition, and disease, as well as human activities such as pollution. Evolution explained by the term “natural selection” that was popularized by Charles Darwin requires three factors:

Variation

Inheritance

Competition These three factors all work together. The reason that variation is important is because there is competition among members of the same species. Namely, more individuals are born than can possibly survive to reproduce. So that means that some will produce more offspring than others. If there is no variation, nothing that gives any one individual an advantage over any other in this competition for survival and reproduction so there will be no evolution.

References: Pages from Wikipedia http://www.birdinginmalta.com/birdspecies.htm http://www.arkive.org/ http://www.rspb.org.uk/wildlife/birdguide/name/b/brambling/index.aspx