Earth Day: Lesser adjutant stork multiplying in fields, says Ornithologist

In a first-of-its kind study in Asia, researchers have found the lesser adjutant stork that was thought to avoid human-modified areas like agricultural landscapes is multiplying.

The study in lowlands of Nepal highlights the high value that agricultural areas can have for conserving even large waterbirds like the lesser adjutant stork.

"What we discovered is rather reassuring and good news for a species that was previously thought to be negatively affected by the agriculture," Nature Conservation Foundation (NCF) scientist K.S. Gopi Sundar told IANS.

He said the lesser adjutant storks breed in small colonies where several pairs build nests together on trees with large canopies, which makes it very easy to spot and monitor them.

"We discovered over 100 nests of the species in a relatively small area that covered parts of the two neighbouring districts of Rupandehi and Kapilvastu. This finding makes this population the largest known breeding population of this species -- a huge and pleasant surprise to begin with," he explained.

"Thanks to the storks being found abundantly in this location, we were able to undertake studies on several key aspects of its biology: the selection of trees for nesting, the factors that affected its breeding success, and finally, some behavioural aspects to understand if agricultural landscapes were diminishing the ability of the storks to raise their chicks."

Lowland Nepal, while dominated with cereal multi-cropped agriculture, still has farmers retain trees on the landscape.

"This they do partly due to sensible agro-forestry laws in the country that encourage the growth of several native tree species that are then used for matchstick making and paper, among other products," said Sundar, who is the IUCN Co-chair of the Stork, Ibis and Spoonbill Specialist Group.

In addition, farmers of lowland Nepal protect certain tree species, like the fig trees, due to religious beliefs that they accord to these trees.

"The largest trees, we found, available for storks to nest, were gigantic fig trees standing alone amid crops. This combination of forestry and religious practices, we found, is working for the lesser adjutant storks," he said.

They largely used the silk cotton tree or semal that farmers grew as part of agroforestry and fig trees that farmers preserved due to religious beliefs.

"We also noticed the trees the storks used for nesting were unusually large relative to the size of trees available on the landscape.

"This suggests that while farmers current practices are working for stork nesting, there needs to be active plans to conserve the large trees that exist on these farmlands," he said.

Breeding success, an exceedingly important aspect of wild species especially those that are thought to be declining, has been rarely studied for the lesser adjutant storks in south Asia.

The researchers -- Roshila and Bijay, both from the Khwopa College near Kathmandu, and their advisor Kamal Gosai, field associate Kailash Jaiswal and scientists Swati Kittur and Gopi Sundar -- recorded 162 chicks taking wing from 101 nests in one breeding season.

"This is a very large number of chicks surviving in one season, suggesting that the lesser adjutant stork population in Nepal is far from declining and that the Lumbini population is likely providing chicks for populations elsewhere," lead researcher Sundar said.

The study finds the stork colonies that have more wetlands around their colonies produced more chicks.

It discovers a situation where one having wetlands along farming is proving to be very beneficial for a large waterbird.

Two, that farmers could continue to use the wetlands as they have for centuries without a need to designate these important habitats as protected areas.

It is becoming apparent that farmers' habits in lowland Nepal is proving to be a win-win for crop production and to support the most important population discovered of the lesser adjutant stork.

The researchers conclude that in the absence of a high level of hunting, this species can adapt very well to farmlands that have a mix of wet and dry crops over different seasons.