Greenfinches

 Greenfinches seem to be making a bit of a resurgence recently. Checking with other ringers it looks like the same is happening throughout the country with higher than usual recent numbers being caught. Greenfinch populations were hit hard by the pulmonary disease trichomonosis. See here.

During July and the early part of August I've ringed more Greenfinches than Goldfinches (usually the most common finch species in my garden). The majority have been juveniles but  a few adults in wing moult as well.

Greenfinches can be sexed as soon as they fledge by the amount of yellow in the primaries and tail. Male birds have yellow on the outer webs of the outer primaries that extends to the feather shaft whilst in females the yellow doesn't reach the shaft.

Below: Male Greenfinch. Euring code 3. A bird born this year and in its first calendar year.

Below: Female Greenfinch. Euring code 3. A bird born this year and in its first calendar year.

Compare the extent of the yellow in the outer primaries.

The photo's below illustrate the differences in the outer tail feathers with the male having more yellow.

The female is a second calendar (Euring 5)year bird and has replaced the right side of its tail probably due to accidental loss. The male is a first calendar year bird (Euring 3).

Finally, the adult birds have all started their post breeding moult. This second calendar year male (Euring 5) is growing P1. Notice P9 is broken whilst P10 (the outermost and smallest primary) isn't visible in this photo. It'll moult all its primaries sequentially from the inside to outside whilst its secondaries will be moulted from the outer one to inner one (closest to body). It’s nice to see Greenfinches doing well after so many years of decline.