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Saturday, November 8, 2014

the new killer of bats ~ not any predators but Wind mills .... in UK !!

For more than 120 years of existence in International cricket, the bat  has undergone lots of changes – perhaps there has not been significant change in the grip, the quality of willow but the weight, perceived quality and weight have.  Present day bats held by star batsmen display not manufacturers’ names but mostly the sponsors on the bats. There are many and varied manufacturers such as : Symonds, Slazenger, Gunn & Moore, Gray Nichols, Puma, BDM, MRF and more….. those days – there were oil and non-oil bats -there were stories of seasoning and oiling the oil bats. At one point time, there were reports that Sunil Gavaskar’s bat had some small pint holes on the back side of the bat which aided him when he drove the ball. The bats of English willow were expertly pressed and there would be procedures of oiling with linseed oil and knocking them over.

Modern bats are usually machine made, the shape of bats have remained in the present form for too long.  Those days Clive Lloyd, Viv Richards and Sandip Patil used heavier bats – now there are many who wield the willow like a bludgeon – resultantly, even a shot not hit in the sweet spot disappears into the crowd, making the life of spinners miserable.  This is not about Cricket but about bats – and their unusual killer !

Bats are mammals of the order Chiroptera, whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, can only glide for short distances. Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits.  Bats are the second largest order of mammals (after the rodents), representing about 20% of all classified mammal species worldwide.  About 70% of bat species are insectivores. Most of the rest are frugivores, or fruit eaters ~ there is common misconception that they are vampires, feeding on blood !  

Bats are present throughout most of the world, performing vital ecological roles of pollinating flowers and dispersing fruit seeds. Many tropical plant species depend entirely on bats for the distribution of their seeds. Bats are economically important, as they consume insect pests, reducing the need for pesticides.   There are many different predators that can create issues for bats. What could consume them really depends on the location where they are at. The size of different species also affects what types of problems they may encounter with different predators.

Other types of flying animals find the bat to be a delicious meal. They include owls and hawks. Snakes are a common predator of bats that consume fruits. The snakes can easily blend into the surroundings of the trees and plants where such fruits grow. In some Western World, raccoons and weasels have been identified as bat predators. In some areas where bats live in trees, there have been reports of house cats capturing them.

For all our appliances and facilities, we use electric power. In our country, mostly the electricity is transmitted through overhead power lines.  There are transformers which supply the domestic current with which most of our devices work.  Electricity generation is the process of generating electric energy from other forms of energy.  Besides the conventional source of electric generation, there is renewable source of energy – the Wind mills.  Tamilnadu has hundreds of windmills nearer Nagercoil and near Coimbatore.  Windmill is a machine that converts the wind energy into electric energy.    Also called wind turbine and WEG [wind electricity generator] – they convert the kinetic energy from the wind into mechanical energy.    The windmills here generally have three blades and the blade  acts much like an airplane wing.

~ and a recent report in Daily Mail reports that these turbines are deadly to bats as they create same air currents as trees, so they fly too close.  It is reported that over  600,000 bats were killed by wind turbines in the U.S. in 2012. In the UK bats numbers dropped by 54 per cent in areas they were put up. Endangered bats are being killed by wind turbine blades because the air currents are similar to those near tall trees, a study shows. It’s feared the legally protected mammals are dying while hunting insects that are attracted by the heat generated by the spinning blades.

The nocturnal creatures are welcomed by farmers across the world as they eat large numbers of insects that usually damage crops. This reduces the amount that farmers have to spend on pesticides and saves millions of new plants that could be obliterated by the creepy crawlies. The researchers say tree-roosting bats suffer higher fatality rates at the windmill  sites than other species and peak during low wind conditions. They used thermal surveillance cameras situated on the ground, near-infrared video, acoustic detectors and radar to monitor bat behaviour at a wind farm in Indiana over several months. During periods of low wind more bats were sighted near turbines than during gales. The frequency with which they approached from a downwind direction increased with increasing wind speeds - but only when the blades turned slower than normal.  The results published in Proceedings of the National Academy of Sciences suggest bats orient toward turbines by sensing air currents.

Trees provide shelter and attract a diverse range of insect species for bats to feed on. Since bats are not able to bore holes or make nests they use whatever gaps are available. The researchers believe tree-roosting bats are attracted to turbines because air currents are similar to those around tall trees that harbour insects on their downwind sides or provide sheltered roosting sites.

Nature is the best teacher, and perhaps over a period of time, bats will learn another trick of survival, to keep away from the wind turbines.

With regards – S. Sampathkumar

24th Oct 2014.

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