Black-winged Stilts Breeding In Sri Lanka's Wet Zone.

Research

On Saturday 16th May 2009, Gehan de Silva Wijeyeratne recorded what is believed to be second record of Black-winged Stilts breeding in the wet zone of Sri Lanka.

He came across a pair with four newly hatched chicks on Diyawanna Udayana Mawatha. This is a few kilometers from the parliament which is on the outskirts of the commercial capital Colombo. Suspecting that more stilts were breeding in the Talanagma Wetland, he found one more pair with a single older chick on the paddy fields opposite the Aluth Wewa. On Sunday 17th May, in the Aluth Wewa paddy fields, he observed what seemed like one more nesting effort still underway. Due to the rapid growth of the paddy, the fate of this attempt could not be ascertained. On Sunday 31 May 2009 he observed what he believed to be another successful breeding attempt at Diyawanna Udyana Mawatha, juding by the defensive behaviour of an adult male. On Sunday 7 June he visited in the afternoon and observed another pair with a single chick. Independently of him, that morning Kithsiri Gunawardana and Deepal Warakagoda had also observed the single chick. This confirms that three pairs of Black-winged Stilts have bred in the wet zone this year. Black-winged Stilts breed in the dry lowlands of Sri Lanka. It is believed that their numbers are augmented by a wintering population from mainland Asia. The breeding of stilts in the wet zone is significant as this is not an isolated aberrant record. It seems that there has been a wider movement of stilts to breed in the wet zone. At the time of writing, this was the second confirmed record. Namal Kamalgoda had observed Black-winged Stilts chicks once before in the early 1990s. It is possible that other previous breeding efforts may have gone un-recorded. However what is notable with the record in May 2009 is that there are at least three pairs of birds witch chicks and a possible fourth breeding effort has been recorded. This raises the question as to why this movement has taken place. One possibility is climate change. All over the world species of birds have been seen to spread from warmer and drier parts of their range to new areas. A good example is the movement of Collared Doves and Little Egrets which have spread from the Mediterranean to Western Europe including the UK. In Sri Lanka there has been a gradual but steady colonisation by the Spotted Dove from the dry zone to the wet zone. Thirty years ago the Spotted Dove was not seen in Colombo. Now it is a breeding resident, albeit in low numbers.  There could be other factors which can explain the range expansion of birds. Loss of habitat, population growth pressures and other pressures on habitats, etc could be factors. Another could be the introduction of plant species or changes in agricultural practices or land use which favours one species of bird over another. However, climate change which causes steady and subtle changes in environmental variables is becoming an influential factor in the changes of breeding ranges of birds.  On 28 April 2009, naturalist Wicky Wickremesekara who was on a field visit with Gehan drew his attention to 14 Black-winged Stilts in the Aluth Wewa paddyfields in the Talangama Wetland. Some looked like they were sitting on nest mounds. Black-winged Stilts are generally quoted as laying eggs on scrapes on the ground or within cowpats for example. It is possible because of the permanent presence of a film of water in the rice paddies, they nested using mounds of vegetation. Now it is confirmed that at least three pairs have successfully bred in the area. The majority of any nests observed on 28 April 2009, would have been inadvertently destroyed by the seasonal ploughing of the fields using buffalos or hand tractors. Odontalogist Karen Conniff had also reported to Gehan aggressive behaviour by the stilts who were even mobbing Painted Storks.  When word spread, a few members of the Ceylon Bird Club visited Diyawanna Udyana Mawatha to see the Black-winged Stilts and the four chicks. As with other species in this scientific order of birds, the young are born covered with down feathers and are mobile and able to feed. The adults are aggressively defending an area of paddy fields from other birds from any species. Gehan de Silva Wijeyeratne has observed the adults mobbing nine different species of birds including a small bird of prey, a Shikra. (As of Saturday 07 June, all four chicks, from the first of the Diyawanna Udayana Mawatha broods, were all alive and well).  Namal Kamalgoda, comments on a previous record he had of Black-winged Stilts with chicks in the wet zone. “I saw breeding Black-winged Stilts in the Kotigahawatha marshes/ paddy fields in the early 1990’s.  I was in the habit of going to the Mahabuthgamuwa temple to get some peace so I could study for my exams. I used to sit by the bo tree and do my reading. The wetland at that time was very rich in bird life and I used to also take a pair of binoculars along with me. The first thing I noticed was the year round presence of Black-winged Stilts and on one of my visit I saw flightless chicks resting under the shade of the adult . I can’t recall much else and due to my limited knowledge at that time, I didn’t consider it unusual. At that time some of the area was under paddy cultivation while others had got water logged. There was a stream that flowed through it and a heronry in a small island in the middle of the marsh. This island was a no go as it was used for brewing kassippu.  In the past I have seen black, yellow and cinnamon bitterns here as well as breeding  jacana, cotton teal and whistling teal. I have even seen garageny here and one pintail.   Sadly this area is now destroyed by invasive water hyacinth and weeds. It is heavily polluted and land filling is rampant. Many slum like house have come up. And an official garbage dump and land fill is in progress. The entire area is water logged and paddy cultivation has long come to a halt. The stream no long flows and one would be hard pressed to find it. The Island remains but even the kassipu brewers leave it alone. This area is walking distance from my house and can be seen from my house roof.” On 11 May 2009 Matjaz Bedjanic and Karen Conniff visited Bodhingala Forest Reserve and saw 8 species of dragonflies, all of which are endemic to Sri Lanka. 

On Sunday 10 May 2009, Kithsiri Gunawardana, Namal and Jackie Kamalgoda were at the Alimankda campsite in Uda Walawe National Park. Around 2.00 pm they heard three gun shots at close range and five minutes later they saw a stranger coming down to the river. They evacuated the camp site and reported it to the park office. It is possible that the reduction in visitation has emboldened poachers.