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Today is World Migratory Bird Day

Sri Lankan bird enthusiasts and experts have all but given up celebrating the World Migratory Bird Day, organized by the African-Eurasian Migratory Waterbird Agreement (AEWA) and the Convention on Migratory Species (CMS). It clearly does not have much relevance in the Asian setting, specifically because the day falls during the hottest time of the year, as opposed to the August to November peak migration period when the climate is just smug for our feathered friends.

Ornithologists argue that celebrating the Migratory Bird Day on May is practical for European and Mediterranean countries, but not equatorial countries like Sri Lanka where the weather is too hot this time of the year. After all, a migratory watch has to be done when there are birds around.

“Just showing pictures of birds is not practical,” said Colombo University Zoology Department Head,

Prof Sarath Kotagama. However, this years Migratory Bird Day theme ‘Energy – make it bird-friendly!’ is universally applicable. In a setting where the demand for renewable energy is ever increasing it is also imperative to make these energy generation methods more sustainable by making them more biodiversity-friendly, bird-friendly in particular.

This year’s theme is of specific significance to Sri Lanka as investors are examining Sri Lanka’s potential for wind power as a renewable energy source. Although wind energy is relatively biodiversity-friendly, it has a certain stigma attached to it due to such circumstances as the Altamont Pass wind power generating disaster.

Thousands of birds die each year as a result of the massive expansion of generating and distributing energy, collisions and electrocution from power lines is rampant. According to the Royal Society for the Protection of Birds (RSPB) appropriately positioned wind farms do not pose a significant hazard for birds. In fact, based on studies RSPB claims that climate change poses a much more significant threat to wildlife.

Kotagama explained that although there is a huge potential for wind power only 20 to 25 percent of the 3500 MW total potential. “Sri Lanka is already 98 percent electrified. The government intends to bring it up to 100 percent by 2018, but at the cost of 15 to 17 percent loss in transmission,” explained Kotagama. Electricity is generated in DC and converted to AC. Some energy loss through this conversion and transmission is invariable. The high potential for wind power was identified in the 1992 wind survey, but any installation of power plants was stalled due to lack of economic viability at the time and the potential ecological repercussions.

The Altamont Pass wind farm has resulted in the deaths of between 25,000 and 100,000 birds over a 20 year period. The Altamont Pass Wind Farm, in central California, is the largest concentration of wind turbines in the world. Built in 1970s, a total of 7,300 wind turbines were added from 1981 to 1993, in an area of 150 km2. Later over the intervening years, the number of turbines has been reduced by about 2,000. Unfortunately the location is also a major bird migration route. As a result of inappropriate placement of the turbines large numbers of birds are killed by collisions annually. At best estimates, the bird kills number over 2,700 per year.

“Energy can’t be 100 percent
bird-friendly,” said Kotagama. He explained that disasters of such magnitude as Altamont Pass, involving large numbers of bird kills have occurred in the past, but reiterated that there is no point in harping on the mistakes.

Kotagama explained that placing the wind turbines in funneling positions is the major cause for such disasters. “Especially birds of prey use these same updrafts,” observed Kotagama. “However the technology is much improved now.” New wind power generating systems run the gamut of heat and motion sensing turbines, bird-friendly color codes that make the turbines easy for birds to spot,  to offshore wind farms, where there is an ever available source of ocean winds.

However, these technologies are too high end for the Sri Lankan wind power generating industry. Besides, where to locate wind turbines, even if in more moderate numbers, is the more important question for Sri Lanka. Kotagama pointed out that the coastal belt from Mannar to Puttalam has great potential for wind power. “But Puttalam is a city and Wilpattu is a National Park. If wind turbines are set up in Kalpitiya it affects the scenery.”

Five windmills were installed in Hambantota in 1995, each generating 300 kilowatts. “Only one bird strike has so far been reported,” said Kotagama. A number of wind farms are operational in Sri Lanka now, Ace Wind Power PL farm at Ambewela and Senok plant at Mampuri to name two.

“Altogether Sri Lanka produces roughly 10 to 15 megawatts of wind power,” said Kotagama. The technology employed in these new plants is quite improved as opposed to that of the first plant in Hambantota. The newest of the planned wind farms to be put up in Mannar would have turbines with a blade-span of 80 meters. “Fewer turbines that can generate more power are preferred over a larger number of turbines with lower capacity,” explained Kotagama.

It seems that birds have also learned to avoid the turbines. “These wind turbines are slow moving, rotating only three to nine meters per minute. Any faster and the turbine would automatically stop functioning,” said Kotagama, explaining that bird strikes in these circumstances are highly unlikely.

What’s imperative is to avoid migration paths of the birds, reiterated Kotagama. “Migration season starts end of August. First the forest birds such as warblers and babblers move in, then from October to November water birds fly in along the northeastern coast and through Mannar,” said Kotagama. Mannar is important because it is an entry point for water birds.

Sites that have ‘wind power potential’ are unique, admitted Professor in Zoology, Devaka Weerakoon. “Ambewela and Mannar are quite different, for example,” said Prof Weerakoon. Vankalai sanctuary is a rich habitat of 20 million migrants. It’s home to many terns and gulls.

Migration paths also depend on monsoonal changes and fishing activities, explained Weerakoon. “Fishermen and birds of Mannar have a mutualistic relationship. Fishing makes it easy for the birds to feed as they catch the fish that escape the fishermen’s nets.” He emphasized that these relationships must be considered when establishing wind farms along the coastline. “Then again if the migrants use the Adam’s bridge as their entry point, we cannot put up a wind farm smack in the middle of the path either.”

When deciding the potential impact of a wind power project, estimating the impact zone as well as understanding the birds’ ecology is equally important. “The larger the flock the greater the probability of impact,” explained Weerakoon. Previous studies conducted in Ambewela shows that egrets fly into the grassland in large flocks to feed. Likewise the wider the impact zone, which is the radius of the rotating blade, the higher the probability of a bird strike, explained Weerakoon. He reiterated the importance of understanding the behavioral patterns of birds when studying the impact of wind farms. “Some birds are diurnal while others are nocturnal and then there are seasonal variations to the birds’ lifestyles as well. All of these must be studied and understood before establishing a wind farm.”

“What we are hitting is more important than how many we are hitting,” added Weerakoon. “Few dozen in a bird population of five million is not a big deal. The whole idea is not to prevent development, but to make it sustainable. It’s a judgment call,” concluded Weerakoon.

Last modified on Friday, 08 May 2015 08:48

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