At the end of an afternoon down by the gravel pits I couldn't resist the temptation of going to look for the Icelandic Gull seen the day before on the Dartford Marshes area, and drove off down the M20 with the sun steadily sinking ahead of me!
I thought there was a possible second winter Icelandic Gull at the front of the small group - an immature Gull drably brown overall and streaky (a bit too streaky probably), although it was a bit darker on the belly (mud perhaps, it did seem to spend time preening its breast), but clearly there were a lot of other options. In the ground photos, it was not possible to see whether there was a dark wingtip/tail as would be seen in a second winter Herring Gull Larus argentatus, or whether there wasn't, in which case the possibility of a second winter Icelandic, Larus glaucoides, might actually still be on the cards!
Eventually the immature gull took off and surprisingly I did manage to get a couple of shots, one of which very surprisingly turned out to have some detail in it! Sadly, however this photo showed that there was a very clear darker training edge to the secondaries, and according to Malling-Olsen and Larsen this makes it a second year Herring Gull.
I was therefore very glad to get this photo - its so nice to have an answer with some degree of confidence, as opposed to a complete "don't know", even if the answer you get is the less exciting of the options! I think I could fairly well exclude junior Lesser Black Backed because of the overall colour pattern,and the bill having a dark tip and paler base, and what appear to be very pink legs. However the photo isn't very clear and a new lens would be an ideal purchase at some stage - a 300 mm is really the entry level lens length for bird photography and I am not really getting close enough to the birds to get good images.
Sunday, 22 January 2012
Windy Whetsted and some Herring Gulls
Quite breezy today, rocking and rolling my quite lightweight tripod. Mild though for the time of year, all things considered.
On the eastern pit on the central roost there was an interesting looking gull - I thought at first from its size and general colour pattern that it must have been a Herring Gull, Larus argentatus. In the UK these are almost always the smaller, less formidable and lighter in colour subspecies argenteus. The adults have a yellow bill with a red spot on the angle of the bill that is known as the gonys. However this bird had no red spot, but a black vertical bar across the bill which is just subterminal. This is likely therefore to be a third winter young bird,
This bird is quite light grey with only a hint of darker streaking on the head. This doesn't look as dark overall especially around the head and neck or as brown in the wing as most of the pictures of the species but ssp argentatus would generally tend to be much darker on the head, and browner on the wing coverts, etc and as this is almost certainly argenteus, it should still be a righteous identification. It certainly isn't dark enough on the hood or in the grey on the wings to be a young Lesser Black-backed Gull, and it is very unlikely to be a rarity. The picture below shows it a long way away, still on the central roost, amongst the smaller black-headed gulls:
You cannot see the black band on the bill very clearly in the picture above, but it shows up rather better below:
This next picture gives a good impression of the squarish head said to be characteristic of Herring Gulls in general although ssp argenteus and females both tend to have somewhat rounder and smaller heads in general in comparison to ssp argentatus and males respectively. It just goes to show the usefulness of taking many photos of the same bird!
There was some degree of darkening to the feathers on the head/neck region (although not as much as in the guidebooks and internet pictures) and this was visible in some of the pictures of the gull with its head facing forward. This is also a good chance to (possibly) agree that the eye is light coloured rather than black, as in the first two years of life:
The grey back of the neck is slightly more visible in this picture where the head is pointed backwards. You may also see a hint of brown on the wings, although this certainly isn't visible in all the photos:
In this photo as the bird is flapping its wings and about to take off, there is a definite impression of brown in the primary and secondary coverts (or scapulars?). In this picture you get a good view of the black bar on the end of the tail, and the streaking around the neck as well:
While in flight the patches of brown on the coverts are quite clearly visible, and maybe there is a hint of light brown on the overall wings. The pattern of black wing tips with white primary tips and a white mirror on P10 fit really well with a third year argenteus bird.
The main problem with the above id is that the bill certainly looks like a third year winter bird, but the overall plumage is still actually a little bit more like an adult winter bird. But in the end I may just have to think this was an issue of the flat light available, and the limited camera lens and usage that I have, and leave the issue until I am more experienced! I should also check all the rarity possibilities!
Here are a couple of younger herring gulls, again Larus argentatus argenteus. These could be first winter or second winter birds, I really can't get the detail at this distance.
This is another photo of the same pair - again you can see the dark fleck on the back of the head of the gull on the left.
Here the gull on the left bends down to pick up something that might be food. The eyes do look dark, as is said to be true for both first and second year birds:
and here is the successful result
and here is the adult common gull, Larus, on the very right, compared in size to several black-headed gulls and the first/second winter herring gull.
.
On the eastern pit on the central roost there was an interesting looking gull - I thought at first from its size and general colour pattern that it must have been a Herring Gull, Larus argentatus. In the UK these are almost always the smaller, less formidable and lighter in colour subspecies argenteus. The adults have a yellow bill with a red spot on the angle of the bill that is known as the gonys. However this bird had no red spot, but a black vertical bar across the bill which is just subterminal. This is likely therefore to be a third winter young bird,
This bird is quite light grey with only a hint of darker streaking on the head. This doesn't look as dark overall especially around the head and neck or as brown in the wing as most of the pictures of the species but ssp argentatus would generally tend to be much darker on the head, and browner on the wing coverts, etc and as this is almost certainly argenteus, it should still be a righteous identification. It certainly isn't dark enough on the hood or in the grey on the wings to be a young Lesser Black-backed Gull, and it is very unlikely to be a rarity. The picture below shows it a long way away, still on the central roost, amongst the smaller black-headed gulls:
There was some degree of darkening to the feathers on the head/neck region (although not as much as in the guidebooks and internet pictures) and this was visible in some of the pictures of the gull with its head facing forward. This is also a good chance to (possibly) agree that the eye is light coloured rather than black, as in the first two years of life:
Here are a couple of younger herring gulls, again Larus argentatus argenteus. These could be first winter or second winter birds, I really can't get the detail at this distance.
.
Thursday, 12 January 2012
Blistering barnacles!
Barnacle geese migrate very large distances very quickly. However the fantastic group of 44 that I saw at the Gravel Pits today were certainly feral and non-migratory - although that itself raises a number of questions! Why is the migratory pattern so strong and consistent in wild birds - and how do feral birds "lose" this tendency?
As a species that is increasing its feral population worldwide as well as undergoing significant expansion and establishing new breeding areas in the wild (in the Baltic increasing from zero to over 17,000 birds in 27 years) it is noteworthy that there is a new Dutch breeding population over 4,000 birds already, apparently also non-migratory (???).
In nature barnacle geese don't exercise particularly more to practice flying in the periods before migrations of thousands of miles at a time. However they do spontaneously increase muscle mass (how?) and may undergo a number of other physiological changes before setting off. Their heavier mass itself may mean that they have to work harder in these periods.
Wild birds tend to trial pair in their first year or two, but then pair more or less for life. They tend to migrate in family groups, and sisters of the same year group tend to nest close to each other, while males tend to disperse a bit more. Do they break out from the family migration groups?
The Greenland birds winter in Ireland and Western Scotland, especially the Hebrides, the Svalbard birds winter in the Solway/Southern Scotland area, while the Novaya Zembla birds (and the newer Faroes population) winter mainly in the Netherlands. The last population is bigger than the other two together.
In the Solway population, the birds always arrive in Caerlaverock and then depart from Rockcliffe, both areas of which are traditional over-wintering grounds. They also now use two further areas around the Solway, in Southerness and in Morecambe Bay, as numbers increase. To indicate the scale of this over-wintering, numbers dropped to about 400 in the 40s, apparently due to disturbance, but are now up to about 25,000, with very significant support!
Populations in the Netherlands are also on the increase, due again to nature conservation measures, although West Germany in contrast has lost most (all?) of its original over-wintering habitat. The increase in over-wintering numbers presumably increases numbers/density on the breeding grounds, potentially having multiple effects on the Artic ecology. Increasing pink-footed goose numbers may increase grubbing and digging, affecting soil temperature and type and amount of plant regrowth, thus possibly affecting barnacle goose and other herbivore numbers indirectly as well as directly. The barnacle geese may however be able to compete relatively better on the short grass swards around the nests, so its not all a one-way street.
The increase in winter protection and feeding opportunities is likely then to be partly responsible for increased populations on the breeding grounds, which may impact on the artic ecosystems primarily via effects on the artic flora and ecosystem functioning. The Svalbard population used to be mainly confined to islands to avoid predation, but has now "spilt over" to mainland cliff sites, presumably less than ideal from the goose's point of view. As the bird is relatively small it is more subject to artic fox predation than other goose species, which are able to breed more freely on the valley bottoms and repel the foxes. Foxes are a major predator, but gulls are mentioned in Russia, and Polar bears, skuas and eagles may also be involved.
It may share breeding grounds with other species such as the pink-footed goose, but at least on the mainlands the barnacle nests on the steepest ground, and needs watery refuges against predation following hatching, while the pink-footed goose is more free to nest and feed on better vegetated areas. As a smaller goose the barnacle is also less able to dig up plant parts such as rhizomes, at any time in the breeding cycle, thus leading to at least some partitioning in resources.
Branta leucopsis is present on its breeding grounds from May or June to August or September where it breeds in small but often closely packed colonies of 5-50 pairs, occasionally singly or in groups of up to 150 pairs. It uses the same nesting sites year after year and sometimes nests among seabird colonies. The females incubate and must not wander too far from the nest to avoid egg predation. They must use a large amount of energy up, and may use all their food items immediately around their nests.
After the young hatch the adults undergo a flightless moult period near the breeding grounds between mid-July and mid-August that lasts for 3-4 weeks. The species then migrates to autumn staging areas in September from which it travels via regular stop-over sites to the wintering grounds, arriving in late-September (??) The Svalbard birds may fly generally fairly directly (?). The return migration begins in April or May, the species moving to spring staging areas where it may be present for 20-30 days before migrating northwards. This spring stop is generally more important because (at least) the females have to have reserves to go virtually into non-feeding incubating mode as soon as the snow melts and nesting can begin (this is of course a fine judgement, dependent upon that year's weather conditions). Such careful judgements may benefit from the social structure and group migration strategy being (generally?) used, ensuring the benefit of experience from the older birds is used.
The species is highly gregarious outside of the breeding season, often feeding in dense concentrations on coastal grasslands during the winter. In winter habitats it roosts on water or on sandbanks near saltmarshes and pastureland.
The species is herbivorous, on the winter grounds apparently preferring well fertilised grass that perhaps has been cut for silage and then grazed, on medium to large sized fields (4 - 10 hectares). Upon landing the group is tight and easily spooked for the first ten minutes at least but may then relax. Larger groups may tend to spread out a bit more to reduce competition for food. The geese may graze cyclically, encouraging a grass regeneration of young plants with a high protein concentration.
Feral groups appear to move about quite a lot in winter presumably consisting of individuals having escaped from collections, with perhaps some resulting offspring. A new small population of Icelandic breeding birds are said to have possibly developed from escapes.
As a species that is increasing its feral population worldwide as well as undergoing significant expansion and establishing new breeding areas in the wild (in the Baltic increasing from zero to over 17,000 birds in 27 years) it is noteworthy that there is a new Dutch breeding population over 4,000 birds already, apparently also non-migratory (???).
In nature barnacle geese don't exercise particularly more to practice flying in the periods before migrations of thousands of miles at a time. However they do spontaneously increase muscle mass (how?) and may undergo a number of other physiological changes before setting off. Their heavier mass itself may mean that they have to work harder in these periods.
Wild birds tend to trial pair in their first year or two, but then pair more or less for life. They tend to migrate in family groups, and sisters of the same year group tend to nest close to each other, while males tend to disperse a bit more. Do they break out from the family migration groups?
The Greenland birds winter in Ireland and Western Scotland, especially the Hebrides, the Svalbard birds winter in the Solway/Southern Scotland area, while the Novaya Zembla birds (and the newer Faroes population) winter mainly in the Netherlands. The last population is bigger than the other two together.
In the Solway population, the birds always arrive in Caerlaverock and then depart from Rockcliffe, both areas of which are traditional over-wintering grounds. They also now use two further areas around the Solway, in Southerness and in Morecambe Bay, as numbers increase. To indicate the scale of this over-wintering, numbers dropped to about 400 in the 40s, apparently due to disturbance, but are now up to about 25,000, with very significant support!
Populations in the Netherlands are also on the increase, due again to nature conservation measures, although West Germany in contrast has lost most (all?) of its original over-wintering habitat. The increase in over-wintering numbers presumably increases numbers/density on the breeding grounds, potentially having multiple effects on the Artic ecology. Increasing pink-footed goose numbers may increase grubbing and digging, affecting soil temperature and type and amount of plant regrowth, thus possibly affecting barnacle goose and other herbivore numbers indirectly as well as directly. The barnacle geese may however be able to compete relatively better on the short grass swards around the nests, so its not all a one-way street.
The increase in winter protection and feeding opportunities is likely then to be partly responsible for increased populations on the breeding grounds, which may impact on the artic ecosystems primarily via effects on the artic flora and ecosystem functioning. The Svalbard population used to be mainly confined to islands to avoid predation, but has now "spilt over" to mainland cliff sites, presumably less than ideal from the goose's point of view. As the bird is relatively small it is more subject to artic fox predation than other goose species, which are able to breed more freely on the valley bottoms and repel the foxes. Foxes are a major predator, but gulls are mentioned in Russia, and Polar bears, skuas and eagles may also be involved.
It may share breeding grounds with other species such as the pink-footed goose, but at least on the mainlands the barnacle nests on the steepest ground, and needs watery refuges against predation following hatching, while the pink-footed goose is more free to nest and feed on better vegetated areas. As a smaller goose the barnacle is also less able to dig up plant parts such as rhizomes, at any time in the breeding cycle, thus leading to at least some partitioning in resources.
Branta leucopsis is present on its breeding grounds from May or June to August or September where it breeds in small but often closely packed colonies of 5-50 pairs, occasionally singly or in groups of up to 150 pairs. It uses the same nesting sites year after year and sometimes nests among seabird colonies. The females incubate and must not wander too far from the nest to avoid egg predation. They must use a large amount of energy up, and may use all their food items immediately around their nests.
After the young hatch the adults undergo a flightless moult period near the breeding grounds between mid-July and mid-August that lasts for 3-4 weeks. The species then migrates to autumn staging areas in September from which it travels via regular stop-over sites to the wintering grounds, arriving in late-September (??) The Svalbard birds may fly generally fairly directly (?). The return migration begins in April or May, the species moving to spring staging areas where it may be present for 20-30 days before migrating northwards. This spring stop is generally more important because (at least) the females have to have reserves to go virtually into non-feeding incubating mode as soon as the snow melts and nesting can begin (this is of course a fine judgement, dependent upon that year's weather conditions). Such careful judgements may benefit from the social structure and group migration strategy being (generally?) used, ensuring the benefit of experience from the older birds is used.
The species is highly gregarious outside of the breeding season, often feeding in dense concentrations on coastal grasslands during the winter. In winter habitats it roosts on water or on sandbanks near saltmarshes and pastureland.
The species is herbivorous, on the winter grounds apparently preferring well fertilised grass that perhaps has been cut for silage and then grazed, on medium to large sized fields (4 - 10 hectares). Upon landing the group is tight and easily spooked for the first ten minutes at least but may then relax. Larger groups may tend to spread out a bit more to reduce competition for food. The geese may graze cyclically, encouraging a grass regeneration of young plants with a high protein concentration.
Feral groups appear to move about quite a lot in winter presumably consisting of individuals having escaped from collections, with perhaps some resulting offspring. A new small population of Icelandic breeding birds are said to have possibly developed from escapes.
Sunday, 18 December 2011
Trying for accuracy in my bird records
I am trying to get much more accurate in my bird counts, for submission to the Kent Ornithological Society (KOS) and the British Trust for Ornithology (BTO). This includes audio recording the data exactly as I count them in!
Bird count seen at or from the pits themselves: 1 Canada Goose, Branta canadensis, 3 Teal Anas crecca, 30 Gadwall, Anas strepera, 1 Wigeon, Anas penelope, 4 Pochard, Aythya ferina, 14 Tufted Duck, Aythya fuligula, 8 Mallard, Anas platyrynchos, 6 Shoveller, Anas clypeata, 1 Goosander, Mergus merganser, 2 Great Crested Grebe, Podiceps cristatus, 10 Little Grebe, Tachybaptus ruficollis, 7 Lapwing, Vanellus vanellus, 83 Black-Headed Gulls, Chroicocephalus ridibundus, 3 Common Gull, Larus canus, 5 Mute Swans, Cygnus olor, 109 Coot, Fulica atra, 9 Cormorant, Phalacrocorax carbo, 2 Jackdaws, Corvus monedula, 2 Carrion Crows, Corvus corone, 2 Magpies, Pica pica, 2 Green Woodpeckers, Picus viridis.
On the path down there were 7 Fieldfare, Turdus pilaris, 1 Blue Tit, Cyanistes caeruleus, 4 Blackbird, Turdus merula, 1 Wren, Troglodytes troglodytes, 3 Jackdaws, Corvus monedula, 3 Woodpigeon, Columba palumbus.
Saturday, 17 December 2011
Nearly Christmas at the Gravel Pits
This is really quite a strange time of year as we get to a whisker away from the shortest day, the 21st December - a particularly emotional time for me as it was my father's birthday. There are both lingering elements of the season drawing to a close, and signs of the new season to come, all mixed in with the feeling of the depths of winter and the excitement of the wintering flocks of birds visiting us, seeking refuge from the icy North.
On the gravel pits the duck are thrilling, with Shoveller numbers starting to build a little bit more strongly now, Teal, and the fantastic female Goosanders (there are now THREE of them, all red-heads), all adding to the semi-resident Gadwall, Mallard and Tufted Duck. I'm still hoping for another Smew this winter, to match last year's cracker! Its difficult to get good photos of the duck at distance, so instead here is a shot of the black-headed gull roost in the second gravel pit, which is always worth a careful check!
Here are some of the group of gulls on the wooden perches to the South of the second gravel pit, and as usual this is a good place to look for Common Gulls, Larus canus. There are 3 in this picture, and these are numbers 4, 7 and 8 counting from the left in this group of 9, the others being the much commoner black-headed gulls! It may be possible to pick out the Common Gulls by their somewhat larger size, and their yellowy-green legs and bills. They are very much inshore gulls, nesting on freshwater lakes and gravel pits, and feeding on the shore and inland. They breed in colonies to which they return in successive generations (monogamous pairs persist year by year), with nearby pairs being more highly related to each other, and a surprising degree of neighbour adoption of wandering chicks. The Birdtrack records indicate numbers in this tetrad between 1 and 4 during 2010, but surprisingly there are no records shown there for 2011.
These three all look like adults, with no obvious black on the bills, although this is very easy to miss - as adults they should have thin black lines on their bills in winter, but no large black patches at the base. They could have migrated into this area for the winter, or they could be part of the resident population in the Southeast. If they have migrated here, they could be from Scandinavia or from Scotland. The total UK population is estimated to be about 50,000 birds, and all those mainly Scottish birds must go somewhere in the winter! Birds are quite subject to predation and do contain quite a diversity of helminthitic parasites, few dominant core species, like other gulls. Males take 2 - 3 years, females 3 - 4 years to start breeding.
Perhaps also they are part of a larger group that roosts here at night, and the others all move off as a flock to feed as a Common Gull group? This seems unlikely as the Common Gulls that Warren usually sees are generally mixed in with the Black-headed Gulls, and there probably aren't enough Common Gulls to make a flock of their own. It's very difficult to get to understand questions like these. Now that I have my eye in a bit, I generally see 2 or 3 birds here during the day, but I've no idea if they are usually the same birds each time, nor whether they are accompanying the Black-headed Gulls or operating independently, for at least part of the time!
Many gull species have increased their populations significantly in the twentieth century, taking advantage of new opportunities at sea and on land, following fishing boats, frequenting waste tips, following the plough, etc. Research in Germany near the Baltic indicated that the Common Gulls there preferred quieter pastures to feed on in flocks, separating their niche from the Black-headed Gulls, which were much more likely to be following the plough on disturbed arable fields. However 20% (!) of gulls following tractors in this study were still Common Gulls, although they spent more time than the BHGs foraging outside the flock, the BHGs tending to follow the tractors more closely.
The German research took seasonality into account, and counted the gulls in different fields, estimating their behaviour patterns. The arable fields in general were available as bare earth being cultivated during migration periods and the winter, but tended to have over-tall vegetation for exploitation during the summer breeding season. The Black-headed Gull numbers fluctuated by season, while the Common Gull numbers were steadier, although both species are migratory.
I wasn't very happy with the statistical approach adopted in this paper, and I think it may have obscured some of the real issues. In addition we don't know where the gulls were when they weren't on the fields, and what they were feeding on as alternate sources! They could be on waste tips, or on the intertidal flats, feeding perhaps on bivalves and polychaetes. Its also worth remembering that there is a lot of flexibility and variation between sites and years in these highly opportunistic birds!
However, according to this research, the Common Gulls spent most of their time foraging in their pastures feeding on earthworms, particularly during autumn and early winter when earthworm biomass is highest, and didn't rest as much as other species. The Black-headed Gulls fed on insects disturbed by the plough, and also spent a little time trying to catch flying insects. They feed hugely at these temporarily abundant resources, and then spend more time resting than the Common Gulls tend to. The BHGs I see by East Lock generally seem to be trying to scavenge things off the ground, either on the newly sown cereal searching from the air, or from the sheep pasture searching on the ground - mostly I don't see Common Gulls on the local farmland at all!
The intensification of arable operations should benefit BHGs, while the move from grassland to arable across Europe may negatively affect Common Gull numbers, particularly as livestock is now more supported by forage and silage, as opposed to traditional pasture grazing, which provides the undisturbed insect and earthworm-rich resources that Common Gulls seem to like.
Back to the blog, this is the causeway across the second lagoon, with great views of the Common Reed fringing the gravel pits,
This is one of the little islands in the shallow lagoon in the first pit, that Monty likes to check for nesting duck if he escapes control - I have to make sure he never does that again.
There are still fruit on the bushes to tempt the visiting winter thrushes, and this is a close-up of two rose hips - the third has already been taken, perhaps by a Fieldfare or Redwing!
The hedgerow roses often seem to have small sections where the leaves remain green and apparently functional, and I've no idea if this is simply an error by the plant, or whether it manages to get a bit more photosynthesis done by developing this little trick! Blackberries seem to retain at least some green leaves for ages.
The rose thorns are retained as well of course, those that haven't got picked up in Monty's coat as he drags through the hedgerows looking for rabbits and squirrels!
By the side of the path to the East of the first gravel pit, there are a number of Goat Willows
On the Goat Willows the buds seem to be swelling - a sign perhaps of the pussy willows to come - if so its got to be a portent of spring hoverflies to come I hope!
This particularly well coloured twig might be a Cornus I suppose?
Meanwhile the lichens continue slowly and steadily to make the most of things by colonising the bark of the oak trees, growing quietly whatever the season! These mainly crustose ones are on the vertical trunk near ground level, greatly magnified,
While these frondose ones are on the stub of a horizontal branch, broken off and rotting further along at the tip
Approaching the lock across the sheep pasture on the return journey, the alder was in its full red-headed glory with its catkins coloured up and getting ready to shed their pollen, another promise of the spring to come. As with so many alders the tree itself leans - I wonder why this is a specific characteristic in so many trees?
Just on the North side of the Lock, I found a blue tit excitedly exploring a dead or dying branch, trying to rip bits of peeling bark off, presumably looking for insects. I got a few shots despite the distance, the blocking branch and the shadows - apologies for the poor quality!.
Looking downriver, the sheep were accompanied by black-headed gulls on the meadow. I could only see a few in this view framed by the bank-side vegetation, but the framing looked rather good!
Just above the lock a big bale of straw had got dropped into the river, by accident or design, and could become a minor hazard to shipping!
On the walk back across the fields, there were some heads of the Common Hogweed, Heracleum sphondylium, and this one has just caught the light on its dried capsellas, just asking to be sown ready for next season!
In the hedgerow wind-break above the hogweed, the Fieldfares and Starlings were prominent in the bare branches and chatting to each other loudly.
Bird count seen at or from the pits themselves: 1 Canada Goose, Branta canadensis, 5 Teal Anas crecca, 57+ Gadwall, Anas strepera, 26+ Tufted Duck, Aythya fuligula, 11+ Mallard, Anas platyrynchos, 15 Shoveller, Anas clypeata, 3 Goosander, Mergus merganser, 3 Great Crested Grebe, Podiceps cristatus, 8 Little Grebe, Tachybaptus ruficollis, 140+ Lapwing, Vanellus vanellus, 3 Common Gull, Larus canus, 3 Mute Swans, Cygnus olor, 110+ Black-Headed Gulls, Chroicocephalus ridibundus, 1 Herring Gull, Larus argentatus, 110+ Coot, Fulica atra, 1 Moorhen, Gallinula chloropus, 3 Grey Heron, Ardea cinerea, 9 Cormorant, Phalacrocorax carbo, 2 Jackdaws, Corvus monedula, 1 Magpie, Pica pica.
In the field at the bottom of Kelchers there were 9 Fieldfare, 7 starling, 5 blue tit, 5 Long-tailed Tit, 4 blackbird, 2 wren, 3 Goldfinch, 5 chaffinch, 7 woodpigeon
On the gravel pits the duck are thrilling, with Shoveller numbers starting to build a little bit more strongly now, Teal, and the fantastic female Goosanders (there are now THREE of them, all red-heads), all adding to the semi-resident Gadwall, Mallard and Tufted Duck. I'm still hoping for another Smew this winter, to match last year's cracker! Its difficult to get good photos of the duck at distance, so instead here is a shot of the black-headed gull roost in the second gravel pit, which is always worth a careful check!
Perhaps also they are part of a larger group that roosts here at night, and the others all move off as a flock to feed as a Common Gull group? This seems unlikely as the Common Gulls that Warren usually sees are generally mixed in with the Black-headed Gulls, and there probably aren't enough Common Gulls to make a flock of their own. It's very difficult to get to understand questions like these. Now that I have my eye in a bit, I generally see 2 or 3 birds here during the day, but I've no idea if they are usually the same birds each time, nor whether they are accompanying the Black-headed Gulls or operating independently, for at least part of the time!
Many gull species have increased their populations significantly in the twentieth century, taking advantage of new opportunities at sea and on land, following fishing boats, frequenting waste tips, following the plough, etc. Research in Germany near the Baltic indicated that the Common Gulls there preferred quieter pastures to feed on in flocks, separating their niche from the Black-headed Gulls, which were much more likely to be following the plough on disturbed arable fields. However 20% (!) of gulls following tractors in this study were still Common Gulls, although they spent more time than the BHGs foraging outside the flock, the BHGs tending to follow the tractors more closely.
The German research took seasonality into account, and counted the gulls in different fields, estimating their behaviour patterns. The arable fields in general were available as bare earth being cultivated during migration periods and the winter, but tended to have over-tall vegetation for exploitation during the summer breeding season. The Black-headed Gull numbers fluctuated by season, while the Common Gull numbers were steadier, although both species are migratory.
I wasn't very happy with the statistical approach adopted in this paper, and I think it may have obscured some of the real issues. In addition we don't know where the gulls were when they weren't on the fields, and what they were feeding on as alternate sources! They could be on waste tips, or on the intertidal flats, feeding perhaps on bivalves and polychaetes. Its also worth remembering that there is a lot of flexibility and variation between sites and years in these highly opportunistic birds!
However, according to this research, the Common Gulls spent most of their time foraging in their pastures feeding on earthworms, particularly during autumn and early winter when earthworm biomass is highest, and didn't rest as much as other species. The Black-headed Gulls fed on insects disturbed by the plough, and also spent a little time trying to catch flying insects. They feed hugely at these temporarily abundant resources, and then spend more time resting than the Common Gulls tend to. The BHGs I see by East Lock generally seem to be trying to scavenge things off the ground, either on the newly sown cereal searching from the air, or from the sheep pasture searching on the ground - mostly I don't see Common Gulls on the local farmland at all!
The intensification of arable operations should benefit BHGs, while the move from grassland to arable across Europe may negatively affect Common Gull numbers, particularly as livestock is now more supported by forage and silage, as opposed to traditional pasture grazing, which provides the undisturbed insect and earthworm-rich resources that Common Gulls seem to like.
Back to the blog, this is the causeway across the second lagoon, with great views of the Common Reed fringing the gravel pits,
Saturday, 10 December 2011
Goldeneye* at Cliffe pools
It was such a lovely day today that I couldn't resist splurging out on the fuel and heading North to Cliffe again. Monty gets a good walk there (at least that's my rationalisation!) and there is always the chance of finding a few things new, to me at least.
The weather was calm but cold, and the puddles still had a little ice at 11:30, despite the sun. There was a fly (blackbottle?) on the flowers of the Alexanders(??) along the access road where it passes the Leopard plant hire offices. I disturbed the kestrel, Subbuteo subbuteo, from the path up the middle by the side of Conoco, and admired the beautiful drake Pochards, Aythya ferina as we went up the path, disturbing a couple of redshank, Tringa totanus which were also on the West side of Conoco.
Near the end of the path on the right there was a small flock of Goldfinches, Carduelis carduelis, feeding on the thistles by the ditch, until I carelessly frightened them up into the Hawthorn, Crataegus monogyna, and then away. I managed to get a poor shot of one in the distance. There was also one with very orange, as opposed to scarlet, facial markings. I wonder if this is a feature of younger birds?
This is the same picture, with the contrast corrected in particular, which makes it look a bit more "Christmassy"!
I got some good views of the Fieldfares, Turdus pilaris, and a Redwing, Turdus iliacus, in the hawthorn bushes towards Flamingo Pool, and then I got to my usual seat - but it was occupied! I sat on the other bench, and was joined by a very pleasant couple, which got Monty far too excited - so he disgraced me by jumping up, and also by trying to chew through his lead in his impatience.
As we had got to the seat, most of the waders were spooked, quite possibly by us, which was a real shame, and they then blew off to the centre of Flamingo, well away. I felt really guilty, I'll have to try to come on weekdays and not disturb birdwatchers over the weekend. Attempting to identify most things I got about 200 Grey Plover, Pluvialis squatarola, 200 Lapwing, Vanellus vanellus, 50 Dunlin, Calidris alpina, about 25 Redshank, Tringa totanus, 10 Shelduck, Tadorna tadorna, 10+ Curlew, Numenius arquata, and 8 or so Little Egret, Egretta garzetta. There were say 35 Great Crested Grebe, Podiceps cristatus, 60 Little Grebe, Tachybatusp ruficollis, and 200+ Coot, Fulica atra, particularly on the far pool.
While talking to the pleasant couple, who were clearly experienced birders, who had migrated from Elmley while the water level was low, I spotted a drake Goldeneye, Bucephala clangula, far down at the far end of Flamingo. Despite the distance, the white sides and white cheek spot were quite easily visible. if there were any females, I'm afraid I didn't see them!
After I had got properly cold, and Monty's behaviour had got much better, we eventually got up to go. At which point, a whole load of Grey Plover, and Dunlin returned to the near beach, together with three Godwits, and I was really pleased to 98% identify one at least of them as a Bar-Tailed Godwit, Limosa lapponica, by the absence of the black band on the tail and the absence of a white band on the wing. I was pretty sure I actually saw the barring on the tail a couple of times.
I headed off down the path towards the Radar pool, and had a good look at the Black-headed Gulls, Chroicocephalus ridibundus, Herring Gulls, Larus argentatus, Lesser Black-backed Gulls, Larus fuscus, and Greater Black-backed gulls, Larus marinus. I thought I saw four or five Common Gulls, Larus canus, as well. At about this point, the gulls got spooked and I saw a fox, Vulpes vulpes, scouting along the far bank, looking for easy prey!
After walking along the path towards the Radar lookout, I picked up the drake Goldeneye again, I was a little bit nearer now, and I tried to get a photo, but it was still a long way away. It was just possible to agree the yellow eye, the very triangular head, the white cheek spot more or less correctly placed and shaped, the greenish gloss to the head, and the slight blackish tint to the area of the primaries, with the wing slightly delineated by a black line. Overall the white sides and neck were good distinguishing features from the drake Tufted Ducks, Aythya fuligunosa, together with the larger overall size, and the very active, fast swimming, often diving, behaviour.
I was particularly pleased to find that the second photo attempt caught what appeared to be the drake vocalising in a sort of "head-straight-up" position, sort of as shown in BWP Volume 1, page 662. Whether it was stirring the water behind with its feet was a bit more difficult to detect, but there was perhaps a hint of it!
The display might have been the centre point of a "mast-head" type movement, with the call, but it wasn't followed by a dive as the next photos were taken fairly quickly afterwards and show further steady swimming continuing to the right. One photo I found on the web shows the same posture in two close together males, but is interpreted as simply drinking!
There are about 200 breeding pairs of Goldeneye in the UK, mainly in the Highlands of Scotland, but most breed near Scandinavia or Russia, and move southwards and possibly westwards in Winter, some ending up here. This one could have come from Germany, Norway, Sweden, Finland, the Baltic States or Russia itself. This drake should head back with most of the others in about March or April. There were supposed to be a couple of ducks at Cliffe as well, but I didn't see them.
They breed in tree-holes, slightly unusual for diving ducks, and the story is they can easily be encouraged by adding nest-boxes to the range of possible breeding sites, thereby raising populations, used for example quite extensively in Finland and Scotland. However although the number of breeding pairs may be raised, this doesn't necessarily increase the number of young that can be bred in a particular area, according to research. This may be due to other density-dependent factors that apply, such as food supply. They feed mainly on insects and other aquatic animals, or turn to plant material, perhaps when animal material gets scarce. Another little trick the females have is brood parasitism, laying eggs in another female's nest.
I also saw a female Marsh Harrier, Circus aeruginosus, with its wings in the characteristic shallow V-shape, drifting low over the marshes behind the Black Barn. This female seems to have been seen quite regularly here.
The weather was calm but cold, and the puddles still had a little ice at 11:30, despite the sun. There was a fly (blackbottle?) on the flowers of the Alexanders(??) along the access road where it passes the Leopard plant hire offices. I disturbed the kestrel, Subbuteo subbuteo, from the path up the middle by the side of Conoco, and admired the beautiful drake Pochards, Aythya ferina as we went up the path, disturbing a couple of redshank, Tringa totanus which were also on the West side of Conoco.
Near the end of the path on the right there was a small flock of Goldfinches, Carduelis carduelis, feeding on the thistles by the ditch, until I carelessly frightened them up into the Hawthorn, Crataegus monogyna, and then away. I managed to get a poor shot of one in the distance. There was also one with very orange, as opposed to scarlet, facial markings. I wonder if this is a feature of younger birds?
As we had got to the seat, most of the waders were spooked, quite possibly by us, which was a real shame, and they then blew off to the centre of Flamingo, well away. I felt really guilty, I'll have to try to come on weekdays and not disturb birdwatchers over the weekend. Attempting to identify most things I got about 200 Grey Plover, Pluvialis squatarola, 200 Lapwing, Vanellus vanellus, 50 Dunlin, Calidris alpina, about 25 Redshank, Tringa totanus, 10 Shelduck, Tadorna tadorna, 10+ Curlew, Numenius arquata, and 8 or so Little Egret, Egretta garzetta. There were say 35 Great Crested Grebe, Podiceps cristatus, 60 Little Grebe, Tachybatusp ruficollis, and 200+ Coot, Fulica atra, particularly on the far pool.
While talking to the pleasant couple, who were clearly experienced birders, who had migrated from Elmley while the water level was low, I spotted a drake Goldeneye, Bucephala clangula, far down at the far end of Flamingo. Despite the distance, the white sides and white cheek spot were quite easily visible. if there were any females, I'm afraid I didn't see them!
After I had got properly cold, and Monty's behaviour had got much better, we eventually got up to go. At which point, a whole load of Grey Plover, and Dunlin returned to the near beach, together with three Godwits, and I was really pleased to 98% identify one at least of them as a Bar-Tailed Godwit, Limosa lapponica, by the absence of the black band on the tail and the absence of a white band on the wing. I was pretty sure I actually saw the barring on the tail a couple of times.
I headed off down the path towards the Radar pool, and had a good look at the Black-headed Gulls, Chroicocephalus ridibundus, Herring Gulls, Larus argentatus, Lesser Black-backed Gulls, Larus fuscus, and Greater Black-backed gulls, Larus marinus. I thought I saw four or five Common Gulls, Larus canus, as well. At about this point, the gulls got spooked and I saw a fox, Vulpes vulpes, scouting along the far bank, looking for easy prey!
After walking along the path towards the Radar lookout, I picked up the drake Goldeneye again, I was a little bit nearer now, and I tried to get a photo, but it was still a long way away. It was just possible to agree the yellow eye, the very triangular head, the white cheek spot more or less correctly placed and shaped, the greenish gloss to the head, and the slight blackish tint to the area of the primaries, with the wing slightly delineated by a black line. Overall the white sides and neck were good distinguishing features from the drake Tufted Ducks, Aythya fuligunosa, together with the larger overall size, and the very active, fast swimming, often diving, behaviour.
There are about 200 breeding pairs of Goldeneye in the UK, mainly in the Highlands of Scotland, but most breed near Scandinavia or Russia, and move southwards and possibly westwards in Winter, some ending up here. This one could have come from Germany, Norway, Sweden, Finland, the Baltic States or Russia itself. This drake should head back with most of the others in about March or April. There were supposed to be a couple of ducks at Cliffe as well, but I didn't see them.
They breed in tree-holes, slightly unusual for diving ducks, and the story is they can easily be encouraged by adding nest-boxes to the range of possible breeding sites, thereby raising populations, used for example quite extensively in Finland and Scotland. However although the number of breeding pairs may be raised, this doesn't necessarily increase the number of young that can be bred in a particular area, according to research. This may be due to other density-dependent factors that apply, such as food supply. They feed mainly on insects and other aquatic animals, or turn to plant material, perhaps when animal material gets scarce. Another little trick the females have is brood parasitism, laying eggs in another female's nest.
I also saw a female Marsh Harrier, Circus aeruginosus, with its wings in the characteristic shallow V-shape, drifting low over the marshes behind the Black Barn. This female seems to have been seen quite regularly here.
Sunday, 27 November 2011
Fungi on the way to the Gravel Pits
The last minute fungi dash to reproduce continues to impress! In the field of seedling wheat to the North of the East lock, an impressive cluster of small mushrooms has recently appeared.
By the tall hedge that crossed the footpath in the meadow to the South of the East Lock, a clump of what looked like some Pholiota have shot up - but I soon realised my mistake I forgot to get a spore print of last weeks finds, despite my iSpot promise!
By the tall hedge that crossed the footpath in the meadow to the South of the East Lock, a clump of what looked like some Pholiota have shot up - but I soon realised my mistake I forgot to get a spore print of last weeks finds, despite my iSpot promise!
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