Eyebrook Reservoir

Welcome to my world: a Canada x Greylag behind four of the subjects of this post at EBR

Previously I posted about a flock of 10 presumed Barnacle x canada hybrids at EBR. Nine remain, and better views over the last couple of days have enabled me to confirm that they are Barnacle x Cackling Goose hybrids. Three more closely resemble Cackling Goose, and one may actually be a Cackling Goose (minima) – see additional images and captions below for more details.

They are unringed, full-winged and wary, but will have come either from a collection in Britain or from feral populations in the Netherlands where Kampe-Persson (2010) commented that “due to mixing and hybridisation with Barnacle Geese the species is hard to count”.

As ever, informed comments will be welcome.

Detail of two of the birds. The one on the right most closely resembles Barnacle, but e.g. the head pattern and upperparts aren’t quite right. The one on the left doesn’t show any features which seem incorrect for Cackling (minima), but given the variation in the rest of the flock I am inclined to be cautious about its identity. 

The hybrid at front resembles Cackling, and even has a small pale crescent on its neck, but note how similar its upperparts are to the hybrids behind and the shadow of Barnacle’s breast pattern (though minima can show something like this). 

Part of the flock in flight

All nine on the water – when swimming they all appear dark-breasted

Part of the flock coming ashore

Part of a flock of 10 Barnacle Goose hybrids at EBR this morning

In rather gloomy conditions at EBR this morning I was surprised to see a flock of 10 Barnacle x canada hybrids. I have seen small numbers of similar hybrids previously (for example one on Islay below), but never anything like this number. Unlike birds on Islay which are assumed to be wild, the EBR birds are likely to be feral. Normally hybrid geese are seen with at least one of the parent species, but in this case the whole flock was made up of hybrids. It would be interesting to know which taxon of ‘canada goose’ was involved.

If anyone has any information about their possible origin, please let me know.

Barnacle x canada hybrid (left), Islay

Presumed hybrid Aythya with Tufted Ducks at EBR (Andy Mackay)

Presumed hybrid Aythya with Tufted Ducks at EBR (Andy Mackay)

A few days ago Andy Mackay sent me these images of an interesting (and tricky) Aythya at EBR. The credit for this one really goes to him, so I’ll let him speak for himself:

It’s the same bird that Tony Taylor and I saw distantly off the Plantation on 1st November, when we decided that it looked OK for a moulting drake Scaup. Seeing it much closer there are a few things that concern me:

1) The mantle vermiculations seem coarse for a Scaup, almost Lesser Scaup-like, although this might just be because I don’t often see them this close!
2) Not shown on any of the photos, but through the scope I could see a definite purple gloss to the head at times when it was head on. From the side it was always obviously green.
3) Distinct pale band behind the black nail on the bill (more obvious in the field than it appears in any of these images), which I don’t recall seeing on a Scaup before, and doesn’t seem to be shown to the same extent by any birds in a quick Google image search.
4) Again, not shown very well in any of my photos, but at times it seemed to have a trace of a tuft or ‘bump’ on the back of the head. At other times though it seemed perfectly round headed.
5) Small size – barely bigger than a Tufted Duck, and not particularly ‘broad-beamed’ when seen front-on.

I saw it wing flap once, and the wing pattern looked like a normal Scaup or Tufted Duck, with white extending well onto the primaries.

Now that I’ve had time to have a good look at the images and compare them with reference material, I agree with Andy that it’s probably a hybrid. After considering various possibilities (including Pacific Scaup) it seems most likely to be a hybrid between Scaup and Tufted, or possibly between Scaup and Lesser Scaup. The features which concern me most are:

head shape – in all the images there is distinct peak on the hind crown, and in the head-on image the crown seems to narrow (should be flatter in Scaup)

size – rather small for a Scaup

mantle vermiculations – possibly OK for Pacific Scaup, but look too coarse for European Scaup

pale behind nail – looks rather similar to Tufted

On its own none of these points would necessarily be conclusive, but taken together they are difficult to explain away by individual variation. Ducks are relatively promiscuous, so hybrids are not uncommon. Although Scaup is roughly ten times more numerous than similar hybrids in L&R, this bird reminds us that subtle hybrids are likely to be overlooked or misidentified unless they are seen very well.

Presumed hybrid Aythya at EBR (Andy Mackay)

Presumed hybrid Aythya at EBR (Andy Mackay)

As often happens, the March count was relatively quiet. Most of the dabbling ducks, especially Teal, have moved on.

There was an increase in migrant Aythya ducks, notably Pochard, and Shelducks as they return to breed.

We had very good views of a Mink by the bridge; this is the second we have seen recently, which suggests that the population may again be growing.

The temperature was about three degrees cooler than yesterday, in overcast conditions, so I was slightly surprised when a Peacock butterfly flew past (my third species this weekend).

The winter wraith: Smew at EBR

The winter wraith: Smew at EBR

This morning’s count began in suitably cold conditions, but the windless, sunny skies soon warmed.

Numbers of Wigeon and Teal remained quite high, and 63 Goldeneye were joined by at least seven Smew (including three adult males). Last weekend there were at least six including four adult males, so in freezing February we can still enjoy watching them.

The biggest surprise appeared towards the end of the count: a Great White Egret with five Little Egrets at the inflow. This was the first individual of this former rarity which I have seen at EBR, and is still an exciting find.

Canada Geese, EBR

Canada Geese, EBR

Despite unusual levels of disturbance which left us with little hope of seeing either Otter or Bittern, we completed this morning’s count in cold, calm weather conditions.

There were lots of hungry birds, and a few Grey Squirrels, on the feeders at Stoke Dry.

Notable sightings included the two long-staying Pink-footed Geese, 708 Teal, and 59 Goldeneye.

Other diving ducks were few in number: not a single Pochard, nor any Smew which though recently an Eyebrook speciality is becoming increasingly scarce.

4 January 2015

4 January 2015

Slightly to my surprise, one of the first birds I saw at EBR in freezing conditions this morning was a Chiffchaff, closely followed by a Little Egret.

As the image shows, the air temperature had still not risen above freezing by late morning.

This will be the third (and, all being well, final) year of mapping for the RBA.

I wish you many discoveries and surprises in the year ahead.