Published On: 2019-11-12
Once widespread in Kathmandu Valley and across Nepal, barn owls are now endangered due to a decline in prey populations and threats from humans.
The first-ever study of barn owls in Kathmandu Valley, carried out by Sabita Gurung for the Small Mammal Conservation and Research Foundation (SMCRF) and Japan’s Nagao Natural Environment Foundation, has found that a decrease in the owl’s rodent prey is affecting its population.
Gurung laid traps for mice and grey house shrews, the main prey of the owl recognisable by its heart-shaped face, and found that both had declined in numbers due to rapid population growth in Kathmandu and the loss of open spaces. This is worrying because owls are an important part of the ecosystem and control the population of grey shrews, which Gurung found make up 80% of the birds’ diet.
Photos: SANJAY THA SHRESTHA
The misconception that the meat of barn owls and Indian eagles can cure paralysis and other diseases has also led to an increase in the poaching of the owls.
Gurung is carrying out further research to identify the barn owl’s food habits, prey availability and challenges to its conservation in the Kathmandu suburbs of Pulchok, Chyamasin, Srijananagar, Kirtipur, Bajrabarahi and Balaju.
The barn owl is one of 23 species of owls in Nepal and was first recorded by British resident and naturalist Brian Houghton Hodgson in 1829. Today, it is categorised as a vulnerable species under the national red list of Nepal birds; anyone found hunting, selling or harming a barn owl is liable to be fined up to Rs30,000 or jailed for 3-9 months.
Considered to be the most beautiful of owl species, the barn owl gets its name from its preference to nest in barns instead of outdoors, signifying its habitat proximity to human settlements.
With an unmarked face and beige lower body, the barn owl is known as the ‘white owl’ in Nepal. Its wide facial disc is actually an antenna that magnifies sound in the same way human ears do. The bird’s acute sense of hearing allows it to be a specialised nocturnal hunter of small mammals.
Barn owls are ultra-light and have soft feathers that muffle its passage through the air, allowing it to fly silently. But because its wings are not waterproof, the bird does not fly when it is raining. Contrary to popular belief, barn owls can see in the daytime but have found a prey niche at night.
Barn owls in Kathmandu Valley were found to feed mainly on shrews, mice, small birds and insects. Since they cannot digest the skull, bones and fur of rodents, the owls spits them out as pellets, which scientists use to study their feeding habits.
Of the 108 pellets Gurung studied recently, 81 belonged to grey house shrews, 13 to mice, 3 to birds and 1 to insects, with some unidentified bones.
The grey house shrew in turn feeds on small insects and worms and has a strong body odour that discourages most predators, except owls and some species of snakes. As shrews live close to human settlements, the owl does too.
However, the use of pesticides and rat poison has reduced the population of rodent and insects, affecting owl colonies in Kathmandu.