All that glitters is not gold, or so the old proverb says and nothing is more apt in the case of this leucistic Grey Heron, initially identified as a Great White Egret, near Stanford on 23rd February.
From a distance it looks interesting but upon closer examination – and before any structural differences become apparent – there are a number of plumage anomalies.
Dark feathers are visible among the white, the most obvious of which are the grey tertials and the rest of the flight feathers on the closed wing. There is a ghost of Grey Heron’s black lateral crown stripe above, and behind, the eye and the legs are pale – much more in line with those of a Grey Heron. Bizarre that this bird should be discovered at the same time as a ‘real’ Great White Egret has put in an appearance in the Nene valley not so very far away …
Mike Baron digiscoped this interesting-looking large gull at Sidegate Landfill yesterday.
In flight over the tip it bore a strong resemblance to a first-winter Glaucous Gull but upon closer examination, however, it clearly shows features more closely associated with Herring Gull.
Although it may be a Glaucous Gull x Herring Gull hybrid I think it more likely to be a leucistic Herring Gull as its head shape does not seem to fit Glaucous, it doesn’t appear to have Glaucous’s beady eye and, as well as the ghosted subterminal tail band, it has an indistinct secondary bar. It is larger, however, than any of the Herring Gulls present!
It does not show a typical striking Glaucous Gull x Herring Gull hybrid bill pattern, which is often virtually identical to first-winter Glaucous but it is not too far adrift from this. Compared with the Herring Gull in the photos, the primaries and tertials are much paler. A pitfall for the unwary Glaucous Gull seeker!
Great White Egrets are now almost annual visitors to the County, even staying to winter in recent years, but the last two or three have paid fleeting visits and they have been difficult to catch up with as a consequence. Conforming to this recent trend, the latest one to occur was found at Kislingbury Gravel Pits on 1st February by Colin Adams.
It was present for only ten minutes after its discovery before being flushed by a dog-walker and flying off east.
This bird no doubt accounted for the report five days later of one flying north-east over Denford. Where had it been during the intervening period?
The first 10 days of February have seen additional scarce gulls arriving at Ditchford GP. In addition to those mentioned in the previous summary a new second-winter Iceland Gull was discovered on 3rd, an adult Mediterranean Gull put in an appearance on 7th and Caspian Gulls were also seen intermittently, with adults there on 1st and 7th, a second-winter on 4th and a different second-winter there on 8th.
Interestingly there might have been a new Glaucous Gull there, too. Dave Warner’s photo, below, taken at nearby Sidegate Landfill on 28th January, appears to show a third-winter with an apparent patchy grey mantle and the dark subterminal band on the bill much reduced in comparison to those of the two ‘regular’ second-winters which have been visiting the site. But maybe long distance, light and camera have conspired to distort reality …
One of the Iceland Gulls was showing distantly on the ice when I was there on Wednesday. In this plumage it sticks out like a sore thumb among the many other large gulls and its small size and delicate proportions are obvious compared, for instance, to the nearby Herring Gull.
Also interesting was this advanced second-winter Caspian Gull, well on its way to second-summer with a reasonably bright bill and very clean neck and breast (just a few small spots at the base of the neck).
This is a fairly typical individual with small head, dark iris, tapered, parallel-sided (though
a little short) bill and a small white mirror on P10, the latter not present on Yellow-legged Gull or argenteus Herring Gull and only on some argentatus Herring Gulls of this age. Second-winter Caspian Gulls are highly variable, some closely resembling first-winters while others can appear much more adult-like.