With only 60 confirmed individuals throughout its range and an estimated world population of fewer than 250 individuals according to the IUCN Red List, White-bellied Heron (WBH) is one of Asia’s rarest birds. This bird species remains at a significant risk of extinction. Despite witnessing five to eight WBH chicks fledge annually, the numbers of these majestic birds has not increased. It is a disturbing observation that puts an impetus on finding out the reasons behind it. Fledging is one of the critical stages for many large birds with high mortality rate. This makes monitoring and rescue of semi-fledged juveniles very important for ensuring juvenile survival and population increase of these critically endangered species.
From May 28 to June 16, 2016, the WBH research team from RSPN and specialist Dr. Lubomir Peske, as part of the White-bellied Heron recovery plan project, were in Burichu, Tsirang. The objective of the trip was to study the ideal age group of WBH juveniles to mount satellite and develop a suitable plan to save WBH. Mounting satellite transmitters is one of the methods that would help in understanding things like distribution, mortality factors, and other life history, and a detailed observation needed to be carried out. All these are crucial information and data components, which would ultimately help in developing a suitable plan to save WBH.
To initiate the tagging program aimed at understanding movement and mortality of the fledged chicks was one of the recommendation of expert consultation held at the December 2015 International White-bellied Heron Conservation Workshop in Bhutan. However, satellite tagging is expensive and a complex method, and the project could only be undertaken with the help of Synchronicity Earth, UK, WWF Bhutan Program Office, and Bhutan Trust Fund for Environmental Consercation (BTFEC).
WBH are shy birds and one has to be extra cautious on approaching it. Likewise, it was only on the fourth day of observation that the team from RSPN was presented with what seemed like an accident turn into an opportunity. One out of the two chicks fell off the nest on to a lower branch of the tree, and in its struggle to get back fell further below getting entangled in a thick bush. The team observed the activity of the fallen chick for eight hours and when it became obvious that its life was at risk, rushed in for its rescue. As this presented a rare opportunity to get close to what otherwise is a shy and elusive bird, the team opted to mount the satellite transmitter on the chick during the rescue mission. Chicks that leave the nest are in a way abandoned by the mother, which spells the end for such unfortunate chicks.
During this time, the other restless chick in the nest suddenly flew out of nest towards Burichu stream and did not return. This was a disturbing sight that set in motion another search and rescue operation. Luckily, the other chick was found the next day, perched on a small shrub beside the stream. The chick was rescued and similarly mounted with a satellite transmitter.
In the end, it was a successful trip that gave a lot of insight on the behavior of these birds. With the tracking system installed on two WBH chicks, the team now can track their movements for the next 3 years, and gather essential data on these birds. This perhaps could be the start of a new beginning for these birds; one that would ensure that their species survives.
Research Team, RSPN