From: Angus Innes <angus_innes@hotmail.com&gt;
Date: 21 May 2020 at 20:35:56 BST
To: Birding Aus <birding-aus@vicnet.net.au&gt;, "wim.vader@uit.no&quot; <wim.vader@uit.no&gt;, "birding-aus@birding-aus.org&quot; <birding-aus@birding-aus.org&gt;
Subject: Birding Aus letter – Redwing song dialects

Dear WimAll

 I shared your interesting e-mail to Birding Aus with a friend of mine, Dr Ernest Garcia (a distinguished ornithologist and co-author of the Handbook – The Birds of the Iberian Peninsula). 

He said that you may find the following paper of relevance to, at least, part of your query. I have not accessed the full paper myself, but the abstract reads as follows: 

"The song dialect situation of the Redwing, Turdus iliac,  in a 765km sq area, 40km north of Oslo, is described based upon registrations during the years 1971-77. The dialect areas are shown to be small, with sharp boundaries between them. Where two dialect populations come into contact some males may sing both dialects. The conformity and stereoypy within the dialect area with regard to song pattern’s is high, and in general, the dialect structure was constant from year to year. Preliminary colour-banding investigations indicate that Redwings, to a very small extent, cross over to the adjacent dialect area."

One of the authors is/was an academic from Trondheim University.

Song Dialects in the Redwing Turdus iliacus

Tore K. Bjerke and Tron H. Bjerke

Ornis Scandinavica (Scandinavian Journal of Ornithology)

Vol. 12, No. 1 (Feb., 1981), pp. 40-50 (11 pages)

Published by: Wiley on behalf of Nordic Society Oikos

DOI: 10.2307/3675903

www.jstor.org/stable/3675903

1. Regional dialects
2. Bird songs
3. Conformity
4. Bird banding
5. Male animals
6. Gene flow
7. Musical structure
8. Flocks
9. Geographical variation

 So, Redwings have been studied, theiir dalect variations confirmed, and the capacity of some birds to learn more than one dialect observed. Is Global Warming (a phenomenon that seems difficult to reconcile with your charming descriptions of long winters and snow in late Spring/almost summer) pushing birds with different dialects further north in Norway?

Angus Innes.

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