Migration and Migrating Birds

 

Every Year thousands of birds fly across the continents covering Vast distances. They seem to fly 15000 to 20000 Kms at a time at a speed of about 20 to 30 KMH. They increase the weight and store energy before they start flying. They have definite pathways within which they fly and keep rest and refueling points along the route. They fly as a flock to protect the foraging efficiency. The precision with which they navigate is immaculate. Lot of Physics is involved in that. They use:

1.    The position of sun to determine the direction

2.    Earth’s magnetic lines to orient themselves to the course

3.    Recognize the constellations and use them to decide the direction.

4.    View the visual identifications like mountains. Rivers, coast line and such other giant objects to ensure their path.

5.    They use the position of Moon, Stars and the Planets.

6.    Deduct the changes in the earth’s magnetic field

Some birds are born with a sense of Navigation and Migration. Others learn from the elders.

They come across several challenges like:

1.    Turbulent Weather Conditions,

2.    Rain and Storm

3.    Un favorable human habits

There are 17 bird sanctuaries in Tamil Nadu. Point Calimere. Vedanthangal and Pulicat aresignificant.

Vettangudi is another protected sanctuary near Thiruppathur. Thousands of birds can be seen there between November and February.

This article describes the same.

THE MIGRATING BIRDS

Vettangudi Bird Sanctuary

 

The Vettangudi Bird Sanctuary in Sivaganga, Tamil Nadu is home to many migratory birds. The Sanctuary is 45 minutes drive from Chettinadu Mansion. It covers 3 villages and its water bodies in an area of 40 hectares. Given below is a list of birds visiting the sanctuary.

·         Grey heron

·         Darter 

·         Spoonbill

·         White ibis

·         Asian open bill stork

·         Night heron: 

·         Painted stork 

·         Little cormorant 

·         Little egret

·         Intermediate egret 

·         Cattle egret

·         Common teal 

·         Indian spot-billed ducks 

·         Pintail

·         Flamingos

 

The best time to visit the sanctuary is between November and February when the weather is pleasant and you can see thousands of migratory birds. Details of 10 birds visiting the sanctuary is given under following pages.

 

 

Grey heron

 

The grey heron is a large bird, standing up to 100 cm (40 in) tall and measuring 84–102 cm (33–40 in) long with a 155–195 cm (61–77 in) wingspan. The body weight can range from 1.02–2.08 kg (2 lb 4 oz – 4 lb 9+1⁄4 oz). The plumage is largely ashy-grey above, and greyish-white below, with some black on the flanks.

Countries: Widespread across Europe, Asia, and Africa; commonly found in the UK, France, Germany, India, and Egypt.

All herons can retract their necks by folding them into a tight S-shape, due to the modified shape of the cervical vertebrae, of which they have 20 or 21; the neck is retracted during flight, unlike most other long-necked birds. The neck is longer in the day herons than the night herons and bitterns.

Ultimately, the herons of our region provide a critical litmus test of the water quality we all depend on — they also play a key role in the aquatic ecosystem throughout our watershed.

The blue heron does NOT mate for life and the life span is about 15 years. The diet of the great blue heron consists of many things. They will eat anything they can catch, though fish is the mainstay. However, frogs, insects and small rodents are also ingested if they happen to come within striking range.

 

 

 

Darter

The darter, also known as the snakebird, is a long-necked water bird that can reach a height of about 70–90 cm (28–35 in) and has a wingspan of approximately 110–125 cm (43–49 in). Weighing between 1–2 kg (2 lb 4 oz – 4 lb 7 oz), its plumage is mostly dark brown and black above, with a lighter, more silvery appearance on the underparts,

Countries: Found in freshwater habitats across Africa, Asia, Australia, and the Americas; notable locations include India, Australia, and parts of Sub-Saharan Africa.

Darters, also known as snakebirds, have elongated necks that they can extend while swimming and retract in flight. They possess 15 cervical vertebrae, giving them remarkable flexibility. These birds are expert divers, primarily hunting for fish underwater. Darters play a vital role in controlling fish populations and indicate the health of aquatic ecosystems. They do not mate for life, and their lifespan is typically around 10–15 years. Their diet mainly consists of fish, but they may also consume amphibians and crustaceans.

 

 

 

 

Spoonbill

 

The spoonbill is a wading bird typically measuring 75–100 cm (30–39 in) in length, with a wingspan of 100–125 cm (39–49 in). It weighs around 1.5–2.5 kg (3 lb 5 oz – 5 lb 8 oz). The bird is known for its distinctive spoon-shaped bill, and its plumage is predominantly white, with some species featuring pink or black accents on their wings.

Countries: Present in Europe, Asia, Africa, and the Americas; found in wetlands in countries like Spain, France, India, and South Africa.

Spoonbills have long, flat bills adapted for foraging in shallow waters, allowing them to sweep side to side while hunting for small fish and invertebrates. They can retract their necks to some extent but are not as flexible as herons. Spoonbills are often seen in large groups, indicating healthy wetland ecosystems. They do not form lifelong pair bonds, and their lifespan is about 15–20 years. Their diet mainly consists of fish, crustaceans, and other aquatic organisms.

 

 

 

White Ibis

The white ibis stands about 65–75 cm (26–30 in) tall, with a wingspan of approximately 100–110 cm (39–43 in) and weighs around 1.3–2 kg (2 lb 13 oz – 4 lb 7 oz). This bird is primarily white, with black wing tips, a long, curved bill, and red facial skin and legs.

Countries: Native to the Americas, especially in the southeastern United States, as well as Central and South America; found in Florida, Brazil, and Argentina.

White ibises have long, curved bills that allow them to probe into mud and shallow water for food. Their necks are flexible but not as elongated as those of herons. They play an important role in the wetland ecosystem by helping to control insect populations and maintain balance in their habitats. White ibises are social birds, often seen foraging in flocks. They do not mate for life and have a lifespan of about 16 years. Their diet consists mainly of crustaceans, insects, and small fish.

 

 

 

Asian Openbill Stork

                                         

The Asian Openbill stork measures about 65–75 cm (26–30 in) in height, with a wingspan ranging from 115–130 cm (45–51 in). It typically weighs between 1.5–2.2 kg (3 lb 5 oz – 4 lb 13 oz). The bird has dark grey plumage with a distinctive gap in its bill, and it features a white neck and belly.

Countries: Predominantly found in South and Southeast Asia; common in India, Bangladesh, Thailand, and Myanmar.

 

Asian Openbill storks have distinctive bills that are uniquely shaped for feeding on snails and molluscs. Their long necks provide excellent foraging capabilities, and they can retract their necks while flying. These storks are an important indicator of wetland health and contribute to pest control in rice paddies. They typically do not mate for life, and their lifespan can reach up to 20 years. Their diet primarily includes snails, fish, and other small aquatic organisms.

 

 

Night Heron

 

The night heron is a medium-sized heron, typically about 55–70 cm (22–28 in) tall, with a wingspan of 100–110 cm (39–43 in) and a weight of around 0.7–1.5 kg (1 lb 8 oz – 3 lb 5 oz). It has a stout body with a short neck, and its plumage is mostly dark brown above, with a paler underbelly and striking red eyes.

Countries: Found worldwide, with significant populations in North America, Europe, Africa, and Asia; present in the USA, Canada, and Japan.

Night herons have shorter, more robust necks compared to their day-active relatives, allowing them to hunt effectively at night. They have 17 cervical vertebrae, facilitating some neck retraction. Night herons play a significant role in controlling populations of fish and insects in their habitats. They are not monogamous and usually have a lifespan of around 15 years. Their diet includes fish, amphibians, and invertebrates, which they catch with their swift strikes.

 

 

 

Painted Stork

 

 

The painted stork is a large wading bird measuring about 80–100 cm (31–39 in) in height, with a wingspan of 150–160 cm (59–63 in). It weighs around 2.5–4 kg (5 lb 8 oz – 8 lb 13 oz). Its striking plumage features a mix of white, pink, and yellow, with a long, curved bill well adapted for feeding.

Countries: Primarily found in South Asia and Southeast Asia; notable populations in India, Nepal, Bangladesh, and Thailand.

Painted storks have long, curved bills adapted for foraging in shallow waters, where they use a unique technique to stir up prey. Their necks are flexible, enabling efficient hunting, and they can retract their necks during flight. They are important indicators of wetland health and contribute to ecological balance. Painted storks do not mate for life, and their lifespan can reach 20 years. Their diet mainly consists of fish, frogs, and crustaceans.

 

 

 

 

Little Cormorant

 

 The little cormorant stands at about 55–65 cm (22–26 in) tall, with a wingspan of approximately 100–110 cm (39–43 in) and a weight of around 1–1.5 kg (2 lb 3 oz – 3 lb 5 oz). This bird has dark plumage, often appearing black or dark brown with a glossy sheen, and features a long neck and a hooked bill.

Countries: Common in South and Southeast Asia; found in India, Bangladesh, Myanmar, and parts of Indonesia.

Little cormorants have long necks that they can extend while diving for fish. They are excellent swimmers and can retract their necks in flight. These birds play a crucial role in aquatic ecosystems by controlling fish populations and are sensitive to water quality. Little cormorants typically do not form lifelong pair bonds, with a lifespan of around 6–10 years. Their diet consists mainly of fish, but they may also eat amphibians and crustaceans.

 

 

Little Egret

 

The little egret is a small to medium-sized heron, typically standing about 55–65 cm (22–26 in) tall, with a wingspan of approximately 88–100 cm (35–39 in). It usually weighs between 0.4–1 kg (0 lb 14 oz – 2 lb 3 oz). The plumage is predominantly white, with long, elegant feathers on the head and neck, and a distinctive black bill and black legs with bright yellow feet.

Countries: Widespread in Europe, Asia, and Africa; found in countries like the UK, France, Italy, India, and Japan.

Little egrets have long, slender necks that they can extend while foraging, allowing them to catch small fish and invertebrates. They possess 18 cervical vertebrae, giving them significant flexibility. These egrets are key indicators of healthy wetlands and contribute to controlling insect populations. They do not mate for life, with a lifespan of about 15 years. Their diet mainly includes fish, crustaceans, and amphibians.

 

 

 

 

Intermediate Egret

 

 The intermediate egret is a larger Heron, measuring around 65–75 cm (26–30 in) in height, with a wingspan of about 100–110 cm (39–43 in). It weighs between 0.7–1.5 kg (1 lb 8 oz – 3 lb 5 oz). This bird has predominantly white plumage, but it can be distinguished by its long, slender neck and bill, as well as its bright yellow eyes and legs, which are often tinged with green.

Countries: Found in a variety of habitats across Africa, Asia, and Australia; common in countries such as India, Sri Lanka, and several African nations.

Intermediate egrets have long, flexible necks that facilitate their foraging habits in shallow waters. With 18 cervical vertebrae, they can extend and retract their necks effectively. They serve an important ecological role in wetland habitats, indicating the health of the environment. They typically do not form lifelong pair bonds, and their lifespan can reach up to 15 years. Their diet primarily consists of fish, insects, and small crustaceans.