This morning I found a bird in one of the nets of which I thought it needed some attention. I found it browner than the Chiffchaffs (Gransanger) that I normally have in my hands. It was also a bit larger than the average Chiffchaff. I always check if it is Chiffchaff or not (primary 6 (P6) should be emarginated). At that moment I noticed that P6 was as long as P3, P4 and P5. Which I found a bit strange. Than I looked up the species in the "Identification Guide to Birds in the Hand", a kind of ringers bible.

And this is what I found:

And in the next picture you find what I had in hand. You can also see that P2 is much smaller than P7 which is also different from the wing formula of the normal Chiffchaff.

If you can think I was rather excited about this. The wing formula is the same as the species with the name Phylloscopus sindianus lorenzii. Nowadays they are considered to be two species. It could be a Bjerggransanger. An extremely rare species in Western Europe.

So I called Hans and we made a description and took some pictures (see below). 

When you look up the Bjerggransanger (Phylloscopus lorenzii) than you will notice that the colors are not the same and therefore we have our doubts. Are colors disive / deciding or are structural features like the wing formula driving. I have no idea. On the other hand, the Mountain Chiffchaff or Eastern Chiffchaff (Phylloscopus sindianus) has a more yellow supercilium.

For me it is still a question, for the time being we put it as a normal Chiffchaff in the database, but we have taken a feather sample and will ask to perform a DNA analysis. So in about half a year we will know the definitive answer.

In total I caught 13 species today (36 birds, 33 new ones and 3 recaptures).

With kind regards and till tomorrow

Robert