North Island myna eradication update

Max (centre) and Jeremy)(right) during training in August (photo Christine Larose)
Max (centre) and Jeremy)(right) during training in August (photo Christine Larose)

The project aimed at eradication Common Mynas from North Island, Seychelles, funded by North Island and overseen by Green Islands Foundation (see blog posts of 21 May, 8 June, 11 August and 7 September) continues. Maxine Little and Jeremy Waters, the current volunteers, began work on 5 August, with Christine and me training them in the basics of the methodology.

Max and Jeremy proved to be quick learners and when we left them a week later they were largely prepared for their working lives on the island. But only with longer experience could they get into the minds of mynas, learning their lifestyle and beginning to understand their behaviour. In the 16 weeks that they have been working alone they have sent weekly reports and copies of the database of information on all the birds they have caught, along with asking pertinent questions (not all of which I could answer!) where necessary. Their knowledge and skills have developed superbly and importantly, they have dedicated themselves to the project and have injected new ideas and experimented with novel approaches to maintain pressure on the myna population. As a result, they have removed 430 mynas (bringing the total since the project started in May to 697 by 24 November) to date and the fall in numbers of these birds in the island is plain to see.

Myna wing during moult. The inner 6 primary feathers, with large white bases, are new, the 7th is new but only part grown, the 8th is missing as the old feather has been shed, and the outer feather is old, bleached brown and will soon be replaced
Myna wing during moult. The inner 6 primary feathers, with large white bases, are new, the 7th is new but only part grown, the 8th is missing as the old feather has been shed, and the outer feather is old, bleached brown and will soon be replaced (photo Chris Feare)

In addition to removing the birds they have been collecting data on all of the those caught, including the state of moult of the wing feathers and the development of the gonads. Prior to Max and Jeremy’s arrival most birds had wing feathers at various stages of moult, shedding old feathers and growing new ones, but by mid-August the vast majority of them had completed the annual moult and had attained their beautiful fresh plumage. Since early October, Max and Jeremy have recorded more and more birds with enlarging gonads, initially in males but more recently in females. This led in November to their finding more and more males with mature testes and females showing enlargement of their ovaries, signalling the onset of the breeding season as Seychelles transitions from the dry south-east trade winds to the wetter north-west monsoon. The final proof of breeding activity came with a female whose ovary (birds have only one) bore scars where mature ova had been shed, and with the discovery that a myna had laid an egg in one of the myna traps!

The egg that had been laid by a female caught in the trap on 24 November (photo Jeremy Waters)
The egg that had been laid by a female caught in the trap on 24 November (photo Jeremy Waters)

The onset of the breeding season of course risks an influx of young birds into the population but we are thankful to have Jeremy and Max as determined myna trappers fired up to eliminate the population as quickly as possible. It is still not clear how many mynas are left but we believe it is less than 100, from a population that “CJ” Havemann, the island’s Environment Manager, and colleagues had estimated to have been up to around 850 at the start of the eradication attempt.

Excellent progress and we hope successful eradication will pave the way for North Island to introduce more of Seychelles’ endemic birds and other endemic fauna, thereby helping to secure the future of species that became alarmingly close to extinction.

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