24 Jan 2013

Clamorous Reed Warblers – Alba Marsh

At the weekend we caught six Clamorous Reed Warblers all of which were re-traps. All birds had been ringed originally at the same site with two birds caught in winter 2011, the earliest one on 8th February 2011. This shows that birds are site faithful and that the Marsh is a suitable place for quite a few wintering/breeding pairs of birds. One thing we noticed was the eye colour on the older birds was orange compared to the dark brown of the younger birds (birds aged through re-trap data). This may be a good way of aging birds if it remains constant – we will keep a check on this to see if it is an age related occurrence or not.


  1. A different species, of course, but this paper gives information on ageing Eurasian Reed Warbler by iris colour (though note that, in my experience, ageing birds using this method beyond second-year can be prone to error) http://www.falsterbofagelstation.se/arkiv/pdf/125.pdf
    I know that there is also some work done on Great Reed Warblers elsewhere in Sweden that has shown (from retraps) that it's also possible to age that species using iris colour but I'm not aware of any published data for this.

    1. Stephen,

      Thanks for the information, very interesting and useful. Maybe eye colour will be valuable for CRW as well?

      Thanks for the link to the paper as well