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Friday, August 28, 2009

Catching-up…

Leave and then the frantic writing of a project proposal to meet the donor deadline have kept me from posting for nearly a month and away from the island for longer, so just a few quick bullets to bring the blog up to date:
  • Great news from Rachel, we have now our third successful fledging of a Seychelles paradise flycatcher on the island which is most encouraging. Breeding activity has now ceased as is usual for this time of year.
  • Vicki and Georgia headed home at the end of July. Their work on the Sooty tern project was very fruitful with numerous landings recorded and very encouraging behaviour displayed. We believe that the birds that visited the island this year are young adults that have not previously bred reconnoitring potential breeding sites for the future. If so this is indeed a very encouraging development. I look forward to receiving the write-ups of their work and also hopefully they will contribute a post or two to the blog.
  • Jildou and Peter have finished their work on the warblers (Acrocephalus sechellensis) on Denis for this visit and dropped by to the office last week to update me on their findings. They were able to catch and ring 99 birds during their stay and estimate that the island population is about 150 - 175 birds. There are now approximately 75 territories on the island. Once independent, young birds leave their natal territories. There are therefore a certain number of birds “floating”. That is to say moving round the island looking for a territory of their own. On Cousin Island where the warbler population is at carrying capacity the birds exhibit cooperative breeding where the young, and particularly the females, often remain in their natal territory and help their parents raise the next generation of siblings. This different life tactic is utilised because the entire existing habitat is occupied and the bird’s evolutionary fitness is optimised by helping to raise its siblings and seeking over time to either inherit the territory or gradually establish a territory off the side of the existing one. The high proportion of unringed birds found in the population during this visit is evidence of ample successful breeding but also suggests a quite high rate of adult mortality. Of particular concern is that Jildou and Peter estimate that 1 in 5 of the adults shows evidence of scarring and injury around the head. Such injuries are not evident on the other island populations and once again suspicion points to the predatory impact of the invasive Mynah bird.

I don’t know when I will be going back to the island, but I do have a backlog of a few things I could post on so I will try and post a couple of times over the next week. Keep checking back for updates…

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