What is the Common Indian Myna (Acridotheres tristis)? The myna is a
bird native to India and South East Asia which has been introduced to various
countries around the world. The myna was introduced to the Seychelles
potentially to manage the number of insects damaging crops and other vegetation,
however this is not confirmed. Is is an aggressive bird that has been known
to injure and kill endemic birds as well as damage the eggs. This has had a severe impact on breeding
success and population numbers of endemic species across the islands.
North Island is working towards
restoring the island to how it was before it became a farm for fruit,
vegetables and coconuts in 1826. Removal of the myna is a huge step in this
process and once completed endemic species can then potentially be
reintroduced. The Myna Eradication Programme is a partnership of North Island,
Green Island Foundations, Chris Feare of Wildwings Bird Management and endorsed
by Ministry of Environment,Energy, and Climate Change. The current programme commenced May 2016 and has since removed 924 myna from North
Island.
Photo: partial view of North island seen spa hill (CWaters)
Our current volunteers, Claire
Waters and Sarah Atkinson took over in April 2017 for the final stages of the eradication.
We are now reaching a very exciting part of the project where we are starting
to see huge progress and can see we are reaching the end of the eradication
process. The eradication of the myna has been successfully completed on two
other islands in the Seychelles archipelago (Frégate and Denis); which have
shown a notable dramatic increase in the native bird population on those
islands. The eradication of the majority of mynas on North Island is already benefiting
the native species on the islands and is thus proving its conservation
importance.
In order to remove the myna, the methodology
has changed since the beginning of the project to adapt to the birds’ changing
behaviour. In order to be successful in removing the mynas, efforts need to be
invested in understanding the bird behaviours and adapting methodologies
accordingly. We are now in the process of carrying out surveys throughout the
day to locate the remaining birds, which are thought to be in very low numbers.
So what do we do every day? Each day
starts at 5:30am where one of the two Myna Eradication Officers, Claire or
Sarah, start with a dawn survey at various locations across the island. This
involves listening and looking for a dawn chorus, which is easily distinguishable
from other birds around the island. Surveys then continue throughout the day,
tracking the remaining birds and covering all areas of the island, from the
plateaus to the top of the hills along the hiking trails. The other volunteer
will begin work at midday, and will carry out the same survey at dusk to locate
the birds as they select a tree to roost in overnight.
Photo: Sarah and Claire observing mynas (ASanders)
Interestingly, a previous Myna
Eradication Programme on Denis Island found that the myna would roost in one
tree together overnight. This has also been suggested to take place around the
world. However, on North Island the myna have all been
found to roost in pairs across the island. This is one example of the differing
behaviour found in the myna on North Island and has made the project more
challenging.
It has been found that as the number
of myna on the island has dropped significantly, their behaviour has begun to
change as well. Their vocalisations have altered to mimic native birds making
it more difficult to locate them. This may be in response to low population numbers
or in an attempt to disguise themselves. It is also possible that juveniles are
learning from native birds in the absence of many adults to learn from. They
have also become less confident and are no longer seen on the ground of the
plateau. In the coming months, as we near completion of the eradication, there
will then be an observation phase of the project, where the island will continue
to be surveyed daily to ensure that we have eradicated all birds, this may take
place for up to 6 months.
Since the start of the myna
eradication, North Island staff have already noticed a significant increase in
the numbers of endemic species. This includes the Seychelles Blue Pigeon (Alectroenas pulcherrima) and the
Seychelles Sunbird (Necttarinia
dussumieri) and is a huge positive step in restoring the island and
conserving the unique wildlife of the Seychelles.
Photo: Seychelles white eye on North island (CWaters)
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