Yesterday a drake green-winged teal was found at Eoligarry, on the flood
created by heavy rain over the past two days. It apparently arrived as
part of an influx of about 10 teal, more than we had previously seen at
Eoligarry. We had a quick look at the bird in fading light yesterday evening
and saw that it had quite dull vertical white stripes, which we put down to
either the poor evening light or the fact that the bird was perhaps not yet in
full plumage having just moulted out of eclipse.
On returning for another look this morning, we were surprised to see
that it actually now had two quite bright vertical white stripes. While we were watching, it disappeared into the vegetation and less than a minute later
we spotted a green-winged teal some 50m to the right on the edge of the
pool, without us seeing it fly or swim there across open water. Surely that couldn't be the same bird? Where there
two green-winged teal present?
Then Ray pointed out another bird which was still moulting, with plenty of
brown feathers in amongst the fresh grey flanks, but with a white mark on both
sides at the top of where the white vertical bar should be. The rest of the bar was obscured by brown feathers. Was this another drake green-winged teal and if so just how many were there? One thing for sure, there was at least
one certain drake Eurasian teal in the group.
The viewing conditions were difficult, the teal were at a distance of about
100m, in and out of the flooded vegetation, it was very windy, misty and dull with
some heavy drizzly showers which soaked the optics. Also the birds were just
coming out of moult, so it was difficult to be certain if the markings we were
seeing, or not seeing, were real or just aberrations of moult. In the end we
decided that we could only be certain that there was one bird present because
we didn't see the dull and bright birds together.
However, the following day we received a message on the Barra birders WhatsApp
group that there were two, probably three green-winged teal on the flood. We
decided to head back later for another look, but unfortunately the teal were
flushed by a buzzard and flew south before we arrived and were not seen again.
Over the next few days the flood subsided to more normal marshy field levels
and we had no further sightings of any teal.
I had taken several videos of the teal on my phone and through the telescope,
all of which are shaky and of poor quality and don't really prove anything,
especially since I had been following around the well marked bird rather than
trying to find other birds.
Most intriguing to me is how many of the females were green-winged teal? The
identification of females is very difficult at the best of times and probably
impossible in the kind of conditions that we had to contend with here.
However, even before the possibility of there being more than one drake was
raised, I had noticed in the field that some of the females looked darker than
I would normally expect and some had a well-marked head pattern of dark
crown, pale supercilium and dark eye-stripe. This is a feature, though not
conclusive, of female green-winged teal as described by Hugh Harrop in a short
paper in
British Birds 112, January 2019: 35-43(opens in a new window).
Apparently the key feature to look out for when
attempting to identify female green-winged teal is the pattern on the
outermost tertial, something which I was not aware of at the time and which
try as I might, I can't see in my videos.