Archive for the ‘Migration’ Category

Gentle marine giant stays more on our waters

April 30, 2017

A whale shark seen with a swimmer off Colombo. Pic courtesy Nishan Perera

As the sightings of whale sharks increase in our waters, experts say the world’s largest fish needs to be protected.

“We still know very little about whale sharks, but the fish is already ‘endangered’ and highly threatened by both target and bycatch fisheries,” says marine biologist from Blue Resources Trust, Daniel Fernando. He made the remarks at a lecture at an event organised by Sri Lanka Sub-Aqua Club this week.

The blue whale is the largest creature on Earth, but since it is a marine mammal, the crown of being the largest fish goes to the whale shark. A whale shark can grow up to 40 feet (12 meters) or more and weigh about 20 tons. The average whale shark is 8 metres long, but the ones found in Sri Lankan waters are 6-7 metres according to Mr Fernando.

Scientifically classified as rhincodon typus, the whale shark called ‘mini muthu mora’ in Sinhala is in fact a species of shark. But unlike other sharks, they do not have teeth and they are filter feeders that depend on plankton. By opening their huge gaping mouths closer to the surface, they scoop in these plants along with any small fish.

Divers have reported more sightings in the seas off Colombo.

Nishan Perera, a marine biologist who has made regular dives in the oceans off Colombo, reported more whale shark sightings in February and March when these fish are seen in our waters. “Two or three whale shark sightings during this period is normal, but this year there were dozens of encounters,” Mr Perera said.

A giant whale shark seen in colombo seas (c) Sanjeev de Silva

The Maldives is a famous destination for whale sharks and queries revealed a lower number of encounters in Maldivian waters when there was an increase in our waters said Mr Perera. The whale sharks have spots on the body and its pattern is unique for each individual. So, the Sri Lankan marine biologists also shared the photos of the whale sharks seen in Sri Lankan waters with other international whale shark databases to verify where they are from.

It could be the same individuals seen in different occasions, but the fact that they are seen more often means that the fish that are used to passing through our waters are staying a little longer than previous years.

Author of the “Sharks of Sri Lanka”; Rex I De Silva says the large number of recent sightings baffle him. He says these fish usually migrate to areas rich in plankton. These areas are where there is an upwelling of nutrient-rich water from the depths. So, it is possible that, fuelled by changes in hydrologic factors, such upwellings are now occurring with greater frequency in our coastal waters. Upwellings encourage the growth of plankton which, in turn, attracts other plankton feeders such as fish. Whale sharks also feed on fish (especially small scombrids) which are attracted to the plankton.

Changing oceanic patterns due to global warming is another reason according to the expert. However, these are just suggestions as to why whale shark sightings have become common in recent years. We just do not have sufficient data to draw firm conclusions, cautioned Mr De Silva.

Howard Martenstyn, another expert, points out that there are more nutrients in the western seaboard compared to 2016 as evidenced by increased rainfall and river outflows and that may explain more whale shark sightings. Mr Matenstyn also reminds us that the number of sightings in the same area does not usually equate to the number of whale sharks, highlighting the need for more supporting data and investigations.

The whale shark is a gentle giant, which allows divers swim with them. They pose no danger to humans but an accidental blow from the powerful tail can cause injury. Experts advise keeping a minimum distance of 1.5 metres from the front of the body and 3 metres from the rear.

The whale shark takes about 15 years to mature to reproduce and is vulnerable to overfishing. Sri Lanka passed laws banning the catching of whale sharks in 2015, but awareness of such regulations, along with implementation, is often lacking points out Daniel Fernando.

Published on SundayTimes on 30.04.2017 http://www.sundaytimes.lk/170430/news/gentle-marine-giant-drawn-to-our-waters-238733.html

Experts urge Sri Lanka to join global effort to protect sharks 
Sharks have slow reproductive cycles and cannot be fished at levels similar to other fish. But sadly, Sri Lanka is among top 20 shark killing countries ranked at 14th place according to a 2013 report by the wildlife trade monitoring network TRAFFIC and the Pew Environment Group.

The Fisheries Department says that steps have been taken to protect sharks. Five species are protected by law, including three species of thresher sharks, oceanic-white tip shark, and the whale shark. The department says it even distributes tools such as de-hookers and line cutters among fishermen that can be used to release sharks caught in nets or hooks.

But more needs to be done to protect these apex predators in our ocean near the top of the marine food chain and help regulate populations of species in the marine ecosystem, the experts say.

Sharks are also important to the economic survival of the fishing industry and have the potential to attract tourists. So Sri Lanka should follow the example of the Maldives and other nations to support international conservation and protection of sharks, marine expert Howard Martenstyn, says.

Several species of shark migrate into different areas of oceans governed by different countries. So to protect them, the Convention of Migratory Species initiated a memorandum of understanding on the conservation of migratory sharks in 2010. Sri Lanka has not yet signed this, but marine experts say this would be a great step forward in recognising the value of sharks within our national and regional waters, points out Daniel Fernando.

Sad plight of a whale shark in Galle, 2014- photo courtesy Lankadeepa

Rare night heron found exhausted

November 30, 2016

A Malayan night heron, a rare migrant bird, appeared in a garden in Thimbirigasyaya this week, spotted by Rajini Jayawardena who lives in Siripa Road last Sunday night.

“It was a relatively large bird and was in the garden, hidden in the darkness. It didn’t fly away even when we went closer to it so I was worried about whether the bird was injured,” Ms. Jayawardena said.

The Field Ornithology Group of Sri Lanka (FOGSL), based at the University of Colombo, was alerted and its MigrantWATCH team identified the bird as a Malayan night heron, which visits the country around this time.

As there were no visible injuries, the team believed the bird was exhausted and disoriented by its long flight of more than 2000 miles and decided to let it recover by itself.

Ms. Jayawardena kept a watchful eye on the heron to keep it safe from cats, crows and other predators. When even by Tuesday the bird did not show any improvement FOGSL decided to capture it and give it a check-up.

Dr. Sampath Seneviratne, who took care of the bird, said it had no injuries – it was simply exhausted. After receiving some first aid, the night heron was released to a better habitat in a Colombo suburban area.

Bird migration is in full swing with star migrants such as the greater flamingo flocking in their thousands in lagoons in the Jaffna peninsula, according to Janaka Bandara, who photographed these birds.

Global conservation giant meets in LankaThe Global Council of BirdLife International, the world’s largest partnership of conservation organisations with partners in more than 120 countries and territories, meets in Sri Lanka this week.

The organisation’s Chief Executive Officer, Patricia Zurita, said the meeting in Sri Lanka will contain important discussions.

BirdLife Global Council’s local partner is the Field Ornithology Group of Sri Lanka (FOGSL), represented by Professor Sarath Kotagama.

The public will have a chance to meet BirdLife International’s members and representatives of its Asian partners at the BirdLife Asian Partnership Bird Fair being held today from 7am-5.30pm at the Thalawathugoda Biodiversity Study Park located near the Kimbulawela end of the Japan-Sri Lanka Friendship Road. The event is free and more information can be obtained from http://www.birdfair2016.wordpress.com.

Published on SundayTimes on 20.11.2016 http://www.sundaytimes.lk/161120/news/rare-night-heron-found-exhausted-217581.html

World’s longest dragonfly migration via Sri Lanka?

November 6, 2011
By Malaka Rodrigo
Last week, a large cloud of dragonflies was observed along the west coast near Colombo. Subsequently, an increase of dragonflies was sighted in many areas islandwide. This sudden appearance of dragonflies in large numbers raised the curiosity of the public.This wave of dragonflies was first reported moving southwards in large numbers on October 20 morning. One of the witnesses, Nashath Haffi of the Field Ornithology Group of Sri Lanka (FOGSL) says while travelling by train he observed this wave around 7 a.m., parallel to the coast, continuously from Moratuwa to Kollupitiya. It is not clear whether the swarm continued further southward.With the aim of investigating the phenomena, the Sunday Times visited the Dehiwala beach, which was in the middle of the recorded route of the dragonflies last Sunday. The residents, mostly fisher folk, when interviewed, confirmed sighting on October 20 a wave of dragonflies flying southwards at a height of about 10 feet. Some of them said it was the first time they had observed such a phenomenon, while others said it was an annual event.

The Dehiwala residents also assisted in catching a few dragonflies still hovering in the vicinity. This dragonfly is about 4.5 cm long, with a wingspan of about 5 cm. The body is a golden colour (dark yellow) with a dark line. The wings are clear and very broad at the base, with a tip near the end. The photos were shared with dragonfly experts and the species identified as Globe Skimmer, or Wandering Glider, scientifically categorised as Pantala flavescens.

Investigations also revealed an interesting fact that this dragonfly is migratory like birds. A Dragonfly migration is believed to be happening annually from India to Africa via the Maldives. Dr. Charles Anderson, who had researched this migration, confirms that, the dragonflies caught in Dehiwala, are the same species involved in the India-Africa migration. Living in the Maldives since 1983, Dr. Anderson continues to observe a sudden influx of dragonflies which raised his initial curiosity. Dragonflies need freshwater to raise their young, as their larvae stage is spent in freshwater.

However, the Maldives is a group of oceanic islands with sand that absorbs all the rainwater it gets. Hence, no freshwater pools are formed even after rain falls. So, apparently, the dragonflies recorded in the Maldives are from elsewhere.

Dr. Anderson started noting down dates of dragonflies seen for the first time in the Maldives, and then compared the data of dragonflies appearing in South India. He found a clear sequence of arrival dates from north to south. According to this data, dragonflies first arrive in Southern India and then in the Maldives. According to his research, each year, dragonflies first appear in the Maldive’s capital, Male, between October 4 and 23, with a mean arrival date of October 21. Quite interestingly, the sighting of the dragonfly wave along the west coast was reported on October 20, which is quite close to the dates they arrive in the Maldives. So, dragonflies seen in Sri Lanka, must also be those involved in this migration.

Dragonflies, though hardy, are small insects – so how can they fly such long distances? Dr. Anderson also attributes that wind patterns help them in this journey. In October, and continuing into November and December, a weather system called the Inter-Tropical Convergence Zone (ITCZ) moves southwards over the Maldives. Dr. Anderson suggests these dragonflies must be flying on these winds at altitudes above 1,000 metres.

Globe Skimmer (Pantala flavescens) caught from Dehiwala

“Ahead of the ITCZ, the wind blows towards India, but above and behind it, the winds blow from India. So, it seems that, the dragonflies are able to reach the Maldives by flying on these winds at altitudes above 1,000 metres” he said.

This could probably be assisting them to visit Sri Lanka too. Since last week, we are experiencing much rain, which could be a result of this weather pattern. Raising the importance of following traditional knowledge, many of the Dehiwala fishing community say these dragonfly waves appear with the change of wind, or ‘goda sulan’, which they are quite accustomed to identifying.

The researcher also found data of sudden appearances of dragonflies in Africa, and when collated, the analysis matches, indicating this migration continues all the way to Africa, more than 14,000 km away.

Migrant Watch – You too can support science

There is a need for extensive research to solve the mysteries of this migration. But the first step would be to monitor where the dragonflies have been sighted in large numbers, which will at least give the coordinates of a possible map. The FOGSL has initiated a programme called MIGRANT WATCH, and invites the general public to forward information on these dragonfly movements. If you have seen swarms of dragonflies recently, please forward location and related dates.

Migrant Watch mainly aims at observing Migrant Birds as a Citizen Science project. Prof. Sarath Kotagama also highlights the importance of observation even by non-experts, as being immensely helpful, as that of the dragonfly migration, which was triggered by Nashath sharing his sighting on October 20. So, he invites all to participate in MIGRANT WATCH, and email the data to fogsl@slt.lk or, post it to FOGSL, Dept. of Zoology, University of Colombo, Colombo 3. Further details can be obtained from 2 501 332 / 0712 543 634 / 0712 543 634.

published on sundayTimes on 06/11/2011 http://www.sundaytimes.lk/111106/News/nws_09.html

Feathered migrants come back to Bundala Wetland

October 30, 2011

It’s the migratory season, and birds from overseas are arriving to stay out the winter months with us. And some of the visitors are old friends, writes Malaka Rodrigo

Sri Lanka is the destination of choice for a variety of migrant birds, and they usually stop over at the same sites every year.

This was proved by two feathered visitors – a Common Redshank and a Lesser Sand Plover – that were captured recently in the Bundala National Park, on the southern coast.A team of bird lovers working for the National Bird Ringing Programme noted that the two birds had been ringed during earlier visits to the national park: the Common Redshank was ringed in 2009, and the Lesser Sand Plover in 2007.

Exhausted Pitta found in Maradana in 2009
Setting up mist nests in Bundala at dusk

Bird migration is a source of fascination to bird lovers. Year after year, during the visiting season, these overseas callers are drawn to Sri Lanka, because of the island’s geographical position, just below the southern tip of the Indian subcontinent. Sri Lanka represents their final destination in their long journey from their homes in northern climates.

The National Bird Ringing Programme, a scientific study of bird migration patterns, is a joint venture of the Field Ornithology Group of Sri Lanka and the Department of Wild Life Conservation. The programme was launched six years ago, in April 2005, at the Bundala National Park.

Migrant birds start arriving in Sri Lanka around the middle of August, ahead of the winter in their native lands. After spending around six months in the island, they return to their breeding grounds towards the end of April the following year. Of the 492 bird species recorded in Sri Lanka, 169 or 36 per cent are migrants. Waders, ducks and coastal birds represent the bulk of the visitors.

The Bundala wetland, about 15 kilometres east of Hambantota, is a paradise for migrants, and has been the base for the ringing programme.

Ringing is a delicate operation, and is generally conducted at dusk. Mist nets (nets with small holes eyes) are strung up around the Bundala lagoon. Birds that get entangled in the nets are taken to the camp and their statistics recorded. A small, individually numbered ring is attached to the birds’ legs.

The ringing exercise takes place four times a year, three during the migratory season and one in July. The three migratory season operations are conducted at the start of the wintering period (September to October); in mid-winter (December to January), and the end of the wintering period (March to April).
Researchers say the ringing programme should be expanded to other locations in the country in order to allow a better understanding of the migrants.

Habitat loss is a serious threat to migrants, says ornithologist, Professor Sarath W. K. Kotagama. The migrants are highly vulnerable to disruption of habitat, such as the cutting down of swathes of forest. These disruptions may threaten the very survival of the bird species, he says.

Watch out for migrants in trouble 

Anyone who cares about birds and wildlife would be interested to know that you do not have to go all the way to the south coast, to places like the Bundala Nature Reserve, to see migrant birds.

Some of the more common migrants visit home gardens as their temporary residence, and even hover around populated urban areas, including the city of Colombo. These visitors include the Indian Pitta (Avichchiya); the Asian Paradise Flycatcher (Sudu-Redi Hora); the Blue-tailed Bee-eater; the Brown Flycatcher, the Barn Swallow, and the Forest Wagtail.

The Field Ornithology Group of Sri Lanka, an affiliate of BirdLife International, organizes “MigrantWATCH”, an opportunity for bird lovers to observe and study migratory birds.

Some of the common migrants need our help in order to survive. The Indian Pitta, for example, arrives in Sri Lanka, usually exhausted after its long journey. Protect the bird if you see it in your garden.

The Sunday Times reported one such Indian Pitta that was rescued in Nugegoda. and another that was rescued in Colombo. Alert residents can help the tired bird by rescuing the troubled Indian Pittas found in their gardens. “This is one of the reasons we started MigrantWATCH,” says a member of the Ornithological Society.

If you spot a troubled migrant bird, or would like to participate in the MigrantWATCH programme, call the Field Ornithology Group (011) 2501332 / 0776248302, or write to fogsl@slt.lk.

Upcoming Migrant WATCH activities:

* Lecture on “Migration and Bundala Birds” by Prof. Sarath Kotagama on Saturday, October 29, at 9.30 am, at the Science Faculty of the University of Colombo (entrance on Thurstan Road)
*  Field visit and workshop to Bundala to study migrants and wader birds: 10 to 13 November

*  Field visit to Mannar : 8 to 11 December
*  Field visits to Thalangama and other wetlands to see migrants

(call (011) 2501332 / 0776248302 for details).

Published on SundayTimes on 30.10.2011  http://www.sundaytimes.lk/111030/News/nws_21.html

From the Himalayas to your doorstep

October 24, 2011

(This is the migration season and during this time of end October, the migrant Indian Pitta has been found several occasions exhausted after their long journey. This is another article done in 2009, where a pitta has been rescued in heart of populated Colombo. Since the same can be repeated this year, the article is repost here, so that you can help if you get an exhausted visitor in your own garden or even at your office..!!)

Sri Lanka, being the southern tip of the Central-Asian flyway, has about 200 migrant birds visiting each year. The Indian Pitta is probably the most beautiful of them all. This bird that breeds in the Himalayan foothills may visit your home garden this season, writes Malaka Rodrigo

Suranga had just finished his morning workload when he heard the raucous cawing of a flock of crows. He looked to see what the commotion was all about. For a moment, he thought a rainbow had fallen from the sky. But it was only a multi-coloured bird which, fluttering weakly, landed near him. Gathering all its remaining strength, it tried to fly but ended up getting stuck in the nearby AC. Suranga with his fellow workers at the Delmege Company rescued the bird, placing it carefully in a cardboard box.

“We never expected to find such a beautiful bird in a congested Colombo neigbourhood like Maradana,” said Chandana Hettiarachchi, Maintenance Manager of Delmege. A bird lover himself, Chandana identified the bird as an Indian Pitta known as Avichchiya in Sinhala and called the Dehiwela Zoological Gardens for advice on how to treat it.

Though the Indian Pitta feeds on insects and worms, this Pitta had happily eaten the fruits and rice offered to him. It was also drinking water showing signs of early recovery, so the rescuers kept the bird in its box in a dark corner without disturbing it. After a few days, its strength regained it flew off to explore its new territory.

This is not the only instance of an exhausted Indian Pitta being rescued in Colombo during the migration season. The Field Ornithology Group of Sri Lanka (FOGSL) too reported two Indian Pittas found in Colombo a few weeks ago. One of them died of exhaustion, but the other recovered and flew away, much to the delight of the rescuers.

“It is not uncommon to find exhausted Indian Pittas at the start of the migration season. They are not sick, but get disoriented after the long journey,” explained veteran Ornithologist Prof. Sarath Kotagama. He advised that the troubled birds be fed with mild sugar syrup and if unable to fly, provided a safe place away from possible predators, until they are fit to fly again.

The Indian Pitta is called Aru-mani-kuruvi in Tamil which means the 6 ’o clock bird and its loud, clear double whistle ‘wheet-tew’, can be heard in the morning and evening around 6 ’o clock. So listen for this unmistakable call – it maybe a visitor from the Himalayas.

If you see a troubled migrant

There may be exhausted late comers who may still land on your doorstep. Dr. Deepani Jayantha offers some tips on helping them.

  • An exhausted or injured bird could be fully conscious, semi-conscious or unconscious. Such a bird should be protected from dogs, cats, rats, crows, shikras etc. Keep them in a dark, quiet and warm place. Handle them gently only if necessary and never force-feed a semi-conscious or unconscious bird.
  • If it is too weak to fly on its own; try giving it small amounts of low concentrated glucose saline with Vitamin C.
  • If the bird is able to fly, release it as soon as possible in a proper environment.
  • If it is necessary to keep the bird for a few days for medical care, provide a proper cage (avoid injurious materials) with a perch protected from predators. Attend to traumatic injuries (broken bones) as necessary – if extensive care is needed, consult a veterinarian
  • Provide clean food and water. 

Published on 2009 on SundayTimes http://sundaytimes.lk/091108/Plus/plus_13.html

Fly, fly, pant, pant.. there’s more to go!

October 24, 2011

What do you do if you come across a dead-beat migratory bird?
By Malaka Rodrigo, Pic by Sasitha Weerasinghe

(This is the migration season and during this time of end October, the migrant Indian Pitta has been found several occasions exhausted after their long journey. This article has been done in 2007, where several such pittas are rescued. Since the same can be repeated this year, the article is repost here, so that you can help if you get an exhausted visitor in your own garden)

“The day has just arrived at my garden in Kalubowila, but the morning sky was gloomy and hinted more rains. ‘Kelie’- my female dog was suspiciously looking at a darker corner in the garage. In the shade, there was a bird. It didn’t move….. It looked at me innocently, through its wide open eyes. ‘Kelie’ was vigilant, but haven’t tried to attack, may be understanding the anguish of the exhausted bird. I have taken it to a veterinary surgeon and later handed over to one of my friend to look after it, as it couldn’t stand on its own. Small worms were fed and the bird showed hints of recovering. However, it was too weak and after three days, on Saturday 10th November, the bird – Slaty-Legged Crake died.

This was the experience of Dulani Dissanayake, a bird watcher who tried to save the life of a migrant bird that would have been exhausted after its long flight.

Over 200 species of birds migrate to Sri Lanka, during the migratory period that starts usually in late August and extends upto to March/April. The bird visitors travel mainly from Europe and northern parts of India. Circulated on the email network of the Field Ornithology Group of Sri Lanka (FOGSL) last week, were two more accounts of migrant Indian Pittas found in home gardens. The Indian Pitta found in Udahamulla in the garden of Sasitha Weerasinghe was also exhausted, but recovered after being fed with water.

The Indian Pitta found at Udahamulla.

But the Indian Pitta at Pelawatte in the garden of Dr. Udaya Kumarasinghe was not that lucky. This Pitta had been observed over the past few years in his garden and Dr. Kumarasinghe had even treated the bird two years ago. On that occasion, he had been seated on his verandah when the Pitta just fell off a nearby tree. He nursed it and the bird recovered in an hour or so and flew away but returned to his garden for the rest of the season. The Pitta came back last year as well. Some of the territorial birds show site tenacity which drives them to the same location year after year.

“It is common to find the migrant birds exhausted after a long flight. Those migrants who travel during the night may be attracted to the light. This is why many birds are found in home gardens. Birds that are attracted to light may collide with windows and get hurt. They can also be easy prey to domestic cats and dogs while resting. Otherwise, birds usually recover on their own,” says veteran ornithologist Prof. Sarath Kotagama. Birds may be found even in the heart of Colombo, where the lights of the buildings attract migrants. But such incidents are rarely recorded, he adds.

Emphasizing the importance of collecting data, Prof. Kotagama invites bird watchers to send their records to the Field Ornithology Group of Sri Lanka (FOGSL) which is also conducting the National Bird Ringing programme in collaboration with the Department of Wildlife Conservation, primarily to study migrant birds.

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Try a little TLC

Usually before the migration, birds feed a lot to gain the strength needed for their long flights. Their bodies are streamlined for flight and in addition, migrant birds employ several other mechanisms to minimize the effort of flying. Larger birds like eagles, cranes and storks soar in the sky, using the thermal upwind. They fly to a higher elevation and then manoeuvre with the wind to move forward with minimum effort.

Larger birds usually migrate during the daytime through a route mostly across a land area. Small birds like Flycatchers and Indian Pittas prefer to travel at night. Not having the advantage of soaring, they have to beat their wings continuously to travel.

If you find an exhausted bird, you need to be calm and not panic the bird further. Chase away the cats, dogs, crows and any other potential predator and leave the bird as it is to recover. If the bird seems to be extremely weak, it could be given water.

Bird Flu: is it really safe..?

There are fears about the spread of Bird Flu through migrant birds. But Avian Influenza has not reached the island or any location that is on the migratory route.Still it is always best to take precautions before handling a sick bird. Using a pair of gloves and cleaning up thoroughly after handling such a bird is indeed wise.

The best we can do is protecting the habitats that are used by these migrants. Start the effort in your own home garden. Plant a tree, make a shade for the exhausted migrants to rest and live in peace during their stay.

Published on 18.11.2007 on SundayTimes www.sundaytimes.lk/071118/Plus/plus00016.html