Bengal Florican: an elusive birds’ disappearing act
Critically endangered with fewer than 1,000 individuals, Bengal Florican (Houbaropsis bengalensis) is an elusive grassland species native to the Indian Subcontinent and Cambodia. In the Indian subcontinent, it is found in small pockets in the Terai region of southern Nepal and northern India along the foothills of the Himalayas and the Brahmaputra Plain.
Male (left) and female (right) Bengal Florican
eBird sightings of the elusive Bengal Florican. Note that almost all of these sightings are from the breeding season
Bengal Florican lives in open tall grasslands with scattered bushes making the exercise of spotting them rather difficult. The males flaunt themselves during the breeding season from February up until the end of June, but during the non-breeding season, the birds effectively vanish! Though the males allow a spotting of themselves, the females in breeding and non-breeding season remain hard to find.
An elusive male in tall grass, its typical breeding habitat. Given their drab colouration, females are harder to spot!
Where do the birds go in the non-breeding season? What’s the enigma behind the birds’ movement during the non-breeding season?
To understand where these elusive and critically endangered birds move in the non-breeding season, a unique collaborative study between India, Nepal and UK was undertaken. Scientists studied seasonal movement of the bird in the breeding range of Terai in Uttar Pradesh (in India) and Nepal.
Between 2013 and 2016, 11 birds were fitted with PTTs (Platform Transmitting Terminal), which are tags used to record the locations of birds at specified intervals through ARGOS satellite overpasses. Needless to say, only trained hands were involved in handling the birds and utmost care was taken to cause no harm to the birds. In addition, researchers also conducted extensive on ground field surveys and recorded locations of birds.
A bird being fitted with a tag by experts (Picture: Dhritiman Mukherjee, BNHS)
A bird released after being tagged (Picture: Dhritiman Mukherjee, BNHS)
In the four years-long study, data showed clear movements of birds from breeding areas to non-breeding regions outside protected areas in both countries which was more prominent in India, less so in Nepal! Most tagged birds in India and western Nepal travelled out of their grassland breeding habitats up to 80 km to seasonally flooded mixed landscape of unmanaged grasslands and low-intensity agricultural areas in the non-breeding season. No wonder they vanish from their breeding sites for more than half the year!
Map showing movement of tagged birds outside protected areas in the non-breeding season. Map modified from Jha et al. 2018.
Data showed that the non-breeding home range of the Bengal Florican is much bigger than its breeding range! In addition, interestingly, the home ranges of birds whose breeding grounds are based in India and Nepal (birds tagged at Pilibhit Tiger Reserve and Shuklaphanta National Park) actually overlap in the non-breeding season! That is, the birds come together in the non-breeding season, however, return back to their respective breeding grounds during the breeding season every year!
Map showing overlap of birds in the non-breeding season with breeding grounds in India and Nepal. Map modified from Jha et al. 2018.
Now that the researchers knew where birds went in the non-breeding season, given the elusive nature and critically endangered status of these birds, they wanted to predict where else these birds could be found, and where they were likely to travel to in the non-breeding seasons. Using information about the habitat and presence data of the birds, researchers used machine learning to model and predict which other places the birds could be possibly found! The models indicated suitable habitats along the length of India- Nepal international border and eastwards on either side of river Brahmaputra in Assam and Arunachal Pradesh! These include areas where Bengal Floricans have never been spotted before, but models predict that they can well be found here!
Highligted areas showing regions where the elusive Bengal Floricans are likely to be found! Map modified from Jha et al. 2018.
The authors recommend urgent surveys in these areas where Bengal Florican could be possibly present. The study also highlights the need for cross border conservation initiatives to revive the bird population and priority conservation action between the two countries to restore and connect surviving fragments where populations of these birds are declining. The findings of this study were used to successfully present its case for inclusion of Bengal Florican into Appendix 1 of the Convention for Migratory Species during the 13th Conference of Parties (CoP) held at Gandhinagar in February 2020.
In conclusion, this study shows that birds move outside the protected areas in the non-breeding season, pressing upon the importance of conservation actions to be extended outside protected areas, in unmanaged grasslands and agricultural fields. Further surveys need to be carried out to confirm the birds’ presence in habitats predicted by models. In fact rapid survey reported the sighting of 4 male individuals in one such predicted habitat in Assam (Warudkar et al. 2019).The species distribution models exhibit tremendous usefulness in predicting suitable habitats in the current scenario of landscape change to make informed conservation and policy decisions. This study calls attention to increased studies and collaborations. Urgent need for conservation actions such as protecting breeding sites, habitat restoration and community awareness are necessary to save the globally threatened Bengal Florican.
Source: Jha, R., J. Thakuri, A. Rahmani, M. Dhakal, N. Khongsai, N. Pradhan, N. Shinde, B. Chauhan1, R.Talegaonkar, I. Barber, G. Buchanan, T. Galligan, P. Donald (2018). Distribution, movements, and survival of the critically endangered Bengal Florican Houbaropsis bengalensis in India and Nepal. Journal of Ornithology 159: 3, 851-866.
Article written by Pratiksha Sail, edited by Devica Ranade. Many thanks to Rohit Jha, first author of the paper, for his valuable assistance with the article.
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