This month is very worm in Japan and many Japanese doubt that maybe is it abnormal weather? However it is not abnormal and almost as usual years. We feel "spring" from worm temperature, and maybe birds also feel like human. Eurasian Wren make breeding territory on February to April in Japan, so November is too fast to make territory. Last week, I observed 4 Eurasian Wren sang. We know that many birds sing on Fall season. Do you know the reason? There are a lot of discussion. Most likely hypothesis is that birds sing on fall under the influence of hormones. Temperature encourage to the hormones. And additional, there are hypothesis that different kinds of hormones from spring work on fall. Wintering territory of Eurasian Wren does not maintained by song. I don't know whether or not the presence of territory. Because I observed some Eurasian Wren in almost same place many time. Judging the age from plumage is possible. After breeding season, Complete molt on adult and partial molt on juvenile. So we can see the plumage contrast on the first-winter individuals. However I never judge age from plumage on field, because Eurasian Wren is too small and too fast movement to judge age.