Monday, December 28, 2015

Studies found out that WBH mortality is high in Bhutan 

Tanden Zangmo/Thimphu 

With roughly 200 White-Bellied Herons (Ardea Insignis) in the world today, herons are
among the 50 rarest bird species on earth and Bhutan alone shelters about 28 herons in
the country with 27 alone in their prime habitat at Punatsangchu valley in Punakha.

As an initiative by the Royal Society for the Protection of Nature (RSPN) in conserving
the habitat of the critically endangered species in the world has established two important
WBH habitat places like Punatsangchu basin, Wangduephodrang dzongkhag and Berthi
in Zhemgang.

Despite numerous initiatives taken up by RSPN in conserving the critically endangered
bird, the mortality rate of the bird has always remained high due to manmade and natural

As per the report released by RSPN, the endangered bird is found dead every year and
RSPN has recorded causalities of 12 individuals since 2003 to 2015 at different locations.

The report stated that in 2011 alone Bhutan lost three WBH roosting in  Phochu vicinity
to the predators and another two in 2014 in its Harrarongchu  habitat where the dead was
unable to determine.

According to the report the dead of the critically endangered bird has happened due to
forest fire, electrocution, wild animals preying on the bird and other  reasons like chick
felling out of the nest, drowning in the river and injuries sustained by the bird.

From among the 12 dead of the critically endangered bird, three individuals have died
due to electrocution, three were predated by the predators, two individuals were died with
unknown reasons, and similarly other four individuals were died  either by falling from
the nest, drowning in the river, injured in the wings and killed during the forest fire.

The report has also stressed that  the research has found out that since 2003 the
population of white Bellied Heron has remained constant contradicting to the Regular
population survey and nest monitoring activities which found out that around 10-12
juveniles produced annually.

 “There is no clear understanding about why there is no significant increase in WBH
population in the country” Report stated

As per the recent population census conducted by Royal Society for Protection of Nature
(RSPN) from 27 February to 3 March this year Bhutan has 14 percent of the world’s total
WBH population.

RSPN has been carrying out WBH population census regularly for last 13 years and their
census has revealed that atleast12 WBH juveniles are produced every year. Hence, the
number of WBH in the country has,on an average remained constant during the entire
survey period.

During the census survey RSPN has counted 14 individuals in their maiden survey in
2003 and since then, the WBH population has seen a steady rise in the Country until 2009
where RSPN recorded the highest of 30 herons in 2008 and 2009.

However, the number has declined for next 4 years of after the survey and the in 2013
survey, RSPN was able to count only 20, which was a drastic decline from the 10 less
highest records of 30.

Yet last year the survey conducted from February 24 to 28, has recorded a rise with two
more individuals from the previous year.

Although the mortality rate of the critically endangered bird has been significant over the
years, Bhutan still have good number of WBH with the aggressive conservation effort
pursued by RSPN in collaboration with Department of Forest and Park Services

RSPN has also completed assessment of Mitochondrial Genetic Diversity of endangered
bird and WBH chick in captivity has reared for the first time.
Apart from the existing conservation effort, RSPN is also carrying out various activities
which include community awareness, long term conservation strategies and “White-
bellied Heron Recovery Plan” project.

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