Thursday, 2 February 2017

Watching the Pennington Flash gull roost

I've spent a fair few late afternoons since Christmas watching the gull roost at Pennington Flash, hoping that a white winger or two might drop in. It's more often than not been a cold and lonely experience, especially as it gets darker, but I've found it quite addictive and even a bit frustrating when I can't get to the flash in time for the roost. I'm not quite sure how I've reached this point, I never used to be all that keen on gulls, especially the immature birds, but over the past couple of years I've started to take a bit more of an interest, even twitching baltic gull in Lincolnshire and Thayer's gull in West Yorkshire. I think it all began a couple of years ago when I visited Cyprus in winter for the first time and saw Armenian and Caspian gulls at Lady's Mile and then last December we went again to Cyprus, and this time I became fascinated by Heuglin's (Siberian) gull.

I've still got an awful lot to learn about gulls, in particular I struggle with yellow-legged and Caspian gulls, even adults, but the only way to learn is to get out in the field and see them and keep asking questions, and that's exactly what I'm trying to do. I'm in no way claiming to be a gull expert or even an expert at watching gulls at Pennington Flash. These are just a few notes for my own benefit which may be of help to others. If you spot any mistakes, please let me know. All of the photos in this post were taken at Pennington Flash in varying degrees of light, weather and distance.They are meant to convey the gull roost experience, not be award winning photos.

Right at the bottom of this post there are a few thoughts on how and where to watch the roost at Pennington Flash.

The white wingers
The highlight of any visit to the gull roost is picking out a white winger, in otherwords a glaucous or an Iceland gull. Since Christmas there has been a single glaucous and at least two Iceland gulls seen on several occasions. These often come into the roost quite late and avoid the pre-roosts, but can also occasionally be seen early morning (before sunrise) and the glaucous gull once stayed until 9:50.

Birds often drop into the roost very late, often after sunset. If they're at the back of the roost they can be 200-300m distant and photography can be very difficult. Yet many of the photos on this post were taken on my telephone through my telescope. It's a miracle that they are identifiable to species, in this case a glaucous gull which was present at the end of January 2017.

On the otherhand this and the next few photos of the same bird were taken with my camera around 9:30am on a day it decided that there was no rush to leave. Apart from the pale primaries and overall pale appearance, I love the black "dipped in ink" tip to the bill.

One thing that I have always found slightly odd about glaucous and Iceland gull is that they are always referred to a juveniles throughout their first winter, unlike other gulls which are usually referred to as 1st winter birds. It's all down to where they breed.

Long distance migrants can delay their moult until they reach their wintering grounds, as with the Siberian / Heuglin's gull I saw in Cyprus in December, but in the case of Siberian gull the birds look very tatty on their wintering grounds with feathers missing, because they begin moulting as soon as they arrive. What confused me is that my photos of the glaucous don't show any sign of moult. Therefore I reasoned, this bird is either a juvenile which has not even started to moult yet (which seems incredibly late) or it's a 1st winter bird which has completed it's moult and is therefore not a juvenile. Yet they're always referred to as juvenile. Turns out it's the former.

Glaucous and Iceland gulls are high arctic breeders and they delay their moult even later than Siberian gull, in fact they don't even begin moulting primaries or secondaries until March of their 2nd calander year. Their first moult is completed by October of their 2nd calander year and they are then in 2nd winter plumage. In otherwords glaucous and Iceland gulls completely bypass 1st winter plumage, which in their case is actually just worn juvenile feathers which can sometimes look very pale.

This particular glaucous gull was a huge bird, much bigger than herring gulls and bigger even than a few of the great black-backs. It was also very agressive!

Glaucous gull alongside a great black-back. Apart from the huge size, the long bill with a black tip and the"short-arsed" appearance of glaucous gull seperate it from Iceland gull. Not particularly obvious from my photos, but glaucous gulls on the water also show a pronounced tertial step.

Perhaps the tertial step is more obvious on this photo. Note the size of the bill and compare with the Iceland gull below.

Juvenile Iceland gull. Superficially similar to glaucous gull, but much smaller and elongated looking. The bill is proportionatly much shorter than glaucous.

This photo of a juvenile Iceland gull was taken 15 minutes after sunset on a dull day at 300m distance! It's clearly a much smaller bird than the glaucous gull with a proportionally shorter bill. Compare size to the nearby herring gulls. On the water it also appears more elongated than glaucous gull.

Adult white wingers are less frequent than juveniles, but occasionally one will drop in as this adult Iceland gull did on 13/02/2017.

Yellow-legged gull

2nd winter yellow-legged gull.

2nd winter yellow-legged gull. Note the elongated appearance of this bird and in particular the length of the primary projection, and compare with L.a. argentatus (below).

3rd winter yellow-legged gull (left hand bird of the three large gulls in the centre of the photo), with all black wing tips and a black band near the tip of the bill.

Yellow-legged gulls are extremely difficult in late winter because there are so many argentatus herring gulls with white heads at this time of year (see below). A combination of mantle colour (slightly darker than argentatus), head shape, bill shape and elongated and uptilted rear end giving the bird a front heavy appearance help confirm the identification of a bird sitting on the water, and none of these are particularly easy in rapidly fading light, when it's a race against time, plus there might be 10,000 birds in the roost and you don't want to miss something else for the sake of concentrating too long on a single bird.

3rd winter yellow-legged gull (centre large adult gull).

4th winter / 5cy yellow-legged gull.

4th winter / 5cy yellow-legged gull.  Obviously darker than the "British" herring gull and black-headed gulls in this photo. Notice also the small white dots in the black primaries when compared to the paler bird.

4th winter / 5cy yellow-legged gull.  Notice how dark the mantle is, even darker than the common gull. A further complication with these large gulls is the possibility of the bird being a hybrid. Some people have commented on seeing this picture that hybrid lesser black-back x herring gull cannot be ruled out.

Three large gulls, from the top argentatus, yellow-legged gull and herring gull. Notice the different mantle shades.

The Larus argentatus argentatus problem

This is a Scandinavian herring gull, Larus argentatus argentatus.

L. a. argentatus (right) with British herring gull. The Scandinavian bird is larger and has a darker mantle, making it superficially like a yellow-legged gull. However it has pink legs and a different wing pattern on the open wing. Scandinavian herring gulls are quite common at Pennington Flash in the winter and a pitfall for the unwary hoping for yellow-legged gull (especially me!). A bird such as this is easily distinguishable from yellow-legged gull due to the streaking on the head and short winged appearance. Yellow-legged gull is longer winged with a completely white head in late winter. However, by late winter some argentatus have themselves developed a white head and some are smaller than this individual, making identification of yellow-legged gull very difficult.

L. a. argentatus (right)

L. a. argentatus (left) with common gull right (asleep). Compare the mantle shade, this argentatus is even darker than the common gull and note the short primary projection.

Mediterranean gulls can be seen in the roost, and this bird is an adult with a near complete hood. Most of the black-headed gulls still have white heads at this time of year, which makes this bird stand out well at the moment.

Leucistic black-headed gull.

The pre-roost in the SE corner.

Where to watch

I'm quite new to gull watching at the Flash, and these next notes are based on my limited experience this winter. I've tried a few different locations to watch from and all of them can be good but they all have their drawbacks too. A telescope is essential wherever you watch from, and bear in mind that the gulls habits may change at weekend when tips are closed, so there may be considerably less birds at around on Saturday and Sunday than there are during the week.

During the period since Christmas, the main roost has been towards the western end of the flash, which is best viewed from near the yacht club in Green Lane due to the position of the setting sun. The birds can also be quite close from here.

However gulls are dropping onto the Flash from the surrounding area throughout the afternoon and from about two hours before sunset pre-roosts form away from the location of the main roost. Over the past few weeks the main pre-roost has been in the south-east corner of the Flash which is invisible from Green Lane, with others around the Spit and in the western bay, though these hold less birds. The temptation is to watch from the south-east corner due to the better light conditions during the formation of the early pre-roost, but the problem with this is that many gulls don't come in until well after the main roost has formed and completely avoid the pre-roosts, and these birds often include some of the more interesting gulls. The main roost is largely not visible and in anycase is against the light from the south east corner. Then about 30 minutes before sunset all of the birds in the pre-roost fly to the main roost leaving the south-east corner devoid of gulls.Of course you can walk to Green Lane from the SE corner, but then it's a long walk back after dark if your car is on the main car park.

The main car park and Horrock's hide can be good places to watch from, especially if there are yachts on the flash since the south-east corner becomes out of bounds for the gulls and on these occasions the early pre-roost can be just off the car park. Horrock's hide is also close to another pre-roost just off the spit. However the main roost is a long way from here and you are looking straight into the sun making viewing impossible on a sunny day.

The only other place I have watched from is the Point.This is a good place to view the pre-roost off the Spit with better light than Horrock's hide and it is close to the main roost, but it's a long way from the south-east corner and on a sunny day large parts of the main roost are silhouetted. The other major disadvantaged to the Point is that you can't park anywhere near it, leaving you with a long, lonely walk which is particularly unpleasant after dark.

After experimenting several times with each of these areas, in my opinion the best way to do the roost  is to choose a day with no yachts, then park in Green Lane and walk to the south-east corner in time for the pre-roost. Then about 30 - 45 minutes before sunset walk back to Green Lane (a 15 minute walk) leaving enough time to spend 45 - 60 minutes at the main roost. The advantage of this is that your car is now in Green Lane.

The other possibility which I haven't personally explored is to do the roost in the morning at least 30 minutes before sunrise. This gives you the added advantage that instead of fighting a battle against the fading light, in theory the light should be getting better all of the time, plus viewing from Horrock's hide is best in the morning. Occasionally some of the birds stay for a couple of hours after sunrise in which case you might get great views, but the overwhelming majority of birds will leave shortly after sunrise and often before.

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