A tale of tails

I've mentioned several times in these posts how important tail feathers are to ringers in ageing birds. This is particularly important in finches at this time of year; and here are a couple of pictures which I hope illustrate the point.

Juvenile tail feathers have been 'on' the birds since they left the nest in Summer 2021. As a result they are usually more worn and tatty ( technical word...) that those of adults which grew new tail feathers in their late summer annual moult. In addition juvenile tail feathers are usually pointed and less robust than adult feathers.

Here are two tails of Linnets we caught yesterday.....

The tail on the left is an adult and you can clearly see they are more rounded than those of the juvenile on the right

Here is the tail of a juvenile Goldfinch--two things to note here. First most of the tail feathers have become worn into points. Secondly, you can see the central two feathers are different. In many finches and buntings, the central tail feathers are sometimes moulted and adult feathers grow in their place. In this case you can see these feathers are less worn and pointed at the tip than the rest of the juvenile tail feathers--but also how much darker and less transparent they are--ie more robust.