It was kräftskiva time last night — crayfish party! It is pretty much what it says it is; an excuse to eat lots of crayfish and drink some snaps.
It had been a nice day with 11 species ringed in at Flommen (totals online — click
Ringing). The most unusual was a Water Rail, trapped in one of our walk-in traps.
Almost as unusual in terms of numbers ringed over the year was this Wheatear:
A really smart 2+cy male. The classic way to age these birds in the hand is using the colour of the inside of the upper mandible: black in adults, pale in young birds — but that is pretty useless in the field. This bird shows a single generation of feathers (1cy birds would show two generations of wing coverts) with dark black flight feathers and broad rounded tail feathers. It's also a damn good-looking bird, virtually lacking any pale fringing to the head feathers. It's unlikely that a 1cy would ever be so well marked.
We also caught a couple of Whinchats.
Which reminds me, I should say something about ageing and sexing them at this time of year. As with Wheatear, the classic ringer's method for ageing this species is using the inside of the upper mandible. All the birds we have caught so far have been 1cy birds with pale upper mandibles.
It's a good starting point but again is completely useless for in the field. So what else can we use?
This bird showed a nice moult in the median coverts. OK, perhaps this is stretching the definition of "useful in the field" but it might be possible with good views...!
One of last Friday's birds, the male, showed two generations of greater covert. GC5 on the left wing had been replaced, presumably following accidental loss. The feather pattern is strikingly different from that of the surrounding juvenile greater coverts; the fringe along the outer web is much thinner, tapering to nothing about halfway up the feather.
Thus on the closed wing the black at the base of the feather meets uninterrupted with the black at the base of the next feather. So, on adult males in autumn at least, there should be a black panel across the greater coverts; on 1cy birds the broad fringes to the greater coverts mean that the black is always interupted; I'm not sure about adult females.
1cy male Whinchat — the arrowed central greater covert gives an idea as to what an adult male would look like in the field at this time of year; note the more expensive area of black compared to the same area on the surrounding juvenile greater coverts.
The tail also offers a clue to ageing, being rather pointed and worn in 1cy birds. It is also the most obvious reliable way of sexing the species. In males, the tail is black and white with a sharp border between the two.
On females, the tail is brown-black and white(ish) with a rather diffuse border between the two.
Continuing the theme of birds with moult limits in their median coverts, this Yellow Wagtail has moulted about half of its median coverts.
Compare this bird to
Sunday's bird, which had moulted all of its median coverts. It's very interesting to note that the wagtail has moulted the outer median coverts and left the inners unmoulted, while the Whinchat above has moulted the inner median coverts and left the outers unmoulted.
Today was considerably slower with just five species ringed. The morning started on a high when a Badger ran across the road in front of us. Then, at Flommen, setting up the nets was amazing. There's occasionally some bioluminescent plankton(?) in the reed bed — I guess it comes in with the salt water that flows down the channel when water levels are high in the Baltic. This morning it was really strong; so much so that I took a few minutes out from putting up the nets to splash about it in. I tried to film it but I ended up with three minutes of nothing. Anyway, it was great fun!
As if bioluminescent plankton didn't make Flommen a cool enough place to ring, you should see the staff...