The German biologist Goetz Rheinwald and I have for
years collected informations and recordings of garden warblers Sylvia borin with
very untypical songs. Until now we have got 31 recordings from Finland, Sweden,
Denmark, Holland. Switzerland and Germany. The recordings have been made
between 1950 and 2009. In order to map the geographical distribution of
these mysterious singers, and maybe with time to be able to disclose the
cause(s) of the abnormal song, we hope that some of you may also
have met such birds. We kindly ask you for any informations and
recordings, you may be able to provide.
The songs of the known 31 birds can be heard
Note that about a third of the birds sing in a rather similar way, with very
short song elements delivered in a rapid tempo, and with the overall song
pattern waving up and down in frequency. All 31 birds sing very differently from
normal garden warblers.
An article on the peculiar garden warblers has
recently been published in German with an English summary (Rheinwald et al.
2009: Gartengrasmücken Sylvia borin als "Rätselsänger". Vogelwelt 130, 135-140).
If you want a pdf of this article, please, contact me.
and best wishes,
Senior Scientist, PhD
Natural History Museum
DK-8000 Århus C