Greenwich Park

Red-Crested and Rosy-billed Pochard on the duck-pond, together with c 50 Black-headed Gulls and 4 - 5 Common Gulls, Larus canus.

College Grounds briefly and Treecreeper!

Very little around in my first quick drive around, nothing on the football pitches or in the trees by the river - where are all the Siskins? It was 9:30 and there were far too many people around already.

However there was a lovely Song Thrush in the northernmost of the three tall limes by the River Bourne behind Elgar block, in fairly full song. And there was a lusty robin singing in the Betula utilis on the path between the Canteen and the Garden Centre.

And then, very encouragingly, I saw a tiny bird flying, undulating slightly, across the College Drive into the three pines by the bike sheds. I was in two minds whether to check on it, but I did follow it up discreetly and to my great pleasure it was a Treecreeper, Certhia familiaris, hopping up the trunks of the pine trees by the bike sheds, one tree after another, wonderful views and actions. I didn't have a camera with me, but I will include a picture taken 3 years ago in the trees in Meadows Field beside the River Bourne on a very snowy day. The white supercilium, the sharp, laterally flattened, beak ideal for probing bark, and the complex pattern on the back of the bird giving it excellent camouflage, all show quite clearly in this photo:

The picture is of a Common or Eurasian Treecreeper, a tiny species of bird which hops UP the side of tree trunks finding insects in the bark crevices, propping itself against the bark with its stiff tail pushing against the grip of its claws. Personally I only see a few of these, if any, a year, as they are very small, quiet, brown and quite inconspicuous, but they are definitely not uncommon birds, widespread and often use larger suburban/rural gardens, parks or woodland where enough older trees are found and insecticides not much used, if ever. The RSPB suggests there may currently be 200,000 territories in the UK, and numbers seem to be on the up in the UK, if anything.

They are VERY fond of trees with crusty bark like Giant Redwood, etc., and they are likely to do well in the tree collection around the College Grounds. They may roost in holes excavated out of Giant Redwood bark. I haven't also seen them passing through my own tiny back garden, where I try to keep a fairly good tree coverage. They are good parents and may raise two broods a year, nesting in old tree bark or woodpiles. British birds, which are said to be of the subspecies brittanica, are said to tend not to migrate or move around very much once settled in territories, and with individual breeding territories of say about 4 Hectares of woodland, only 200 m x 200 m, within larger areas of woodland, I reckon this bird might perhaps never have been out of the College grounds in its life (totally dependent upon the habitat within the College), and at any one time there are likely to be several birds most years across Broadview gardens and around the college buildings and nearby gardens. However an alternative view is that they do wander quite a bit in the winter, and this may be exploring the College from a base in the woods. 

They often join flocks of tits in the winter, and may be quite mobile at that season. Bird Study (1989) 36, 99-104. The exploitation of Tits Parus species, Long-tailed Tits Aegithos caudatus and Goldcrests Regulus regulus by Treecreepers Certhia familiaris: a behavioural study. I.G. Henderson, The University of Leicester. The variation of Treecreeper Certhia familiaris pecking rates was studied in response to variations in the size of associating flocks of Tits Parus species, Longtailed Tits Aegithos caudatus and Goldcrests Regulus regulus. A significant and positive relationship was detected. The actual frequency of association between tits and Treecreepers was investigated, and the analysis and discussion of niche separation and the effects of temperature are also included. It is suggested that increased vigilance afforded by associating with tit flocks allows Treecreepers to adjust their own time budget, away from vigilant behaviour and towards extra feeding. This paper suggests that if the experimenter saw a flock of Tits in the winter, the majority of them did not contain Treecreepers. However the majority of Treecreepers seen in the winter during this research were seen in a Tit flock. The flocks tended to be bigger in colder weather, but after temperature was accounted for, the pecking rate increased in larger flocks, suggesting that the advantage of associating in flocks allowed the Treecreeper to concentrate more on feeding than on vigilance. The Treecreeper is of course not feeding within the same niche as the Tits.

Warren tends to see them very regularly in the Wet Woods and Scrubby Woods, although they do come into his garden, fairly close to some woodland, from time to time as well, where they search for food in a (obviously rough-barked) elder tree. In general they can be thought of as old-growth woodland birds, that may be quite strongly impacted by habitat fragmentation and urbanisation. Woodland fragmentation tends to impact upon nesting success via nest predation (e.g. mustelids), which is often significant, according to Finnish experimentation. The species was also shown by long-term monitoring to be gradually lost from around the Brent Reservoir as the area was built over. Not generally to be found on bird-tables!

Treecreepers are probably most closely related to wrens, a relationship that fits with their size and colouring. Treecreepers have very long rear claws (long curved nails), which presumably help them to grip the bark more easily. The beak is quite scythe-shaped, mainly pale on the lower mandible (especially hear the base), and dark on the upper mandible. The bright buffish "zigzagy" band with dark edges on the wing is quite visible, this runs across the base of the secondaries and the middle of the primaries. The spotty bars further forward on the wing are also quite clear, which I think are the tips of the greater and lesser coverts. The thin streaky patterns on the cap are also quite reliably seen. 

The British form or subspecies is known as britannica. It is darker than the nominate continental form C. f. familiaris, commonly found across Northern Europe, and also further East in Europe. It is also duller, with less obvious ghostly marks on the upperside, duller white underneath, and in some individuals buffy under the tail. The juvenile is rather spottier as opposed to streaky on the upperparts when compared to the adult, and the underparts are again a duller white, as well as distinctly buffier under the tail. There are at least half a dozen more subspecies across Europe as a whole.

I hope to see this one, its mate, or perhaps some of their young, again in 2015 if I keep my eyes open in the grounds. It should nest in April/May or so, if it can find a mate and a suitable nest site. The males may court the females by a delicate spiralling dance around a tree, and wing-fluttering. They are generally monogamous, but with the females doing most of the nest building and care of the young. 

Voice high-pitched and sibilant. 

They may live for up to 7 years, say. 

Food availability and the male's role in parental care in double-brooded Treecreepers Certhia familiaris. Markku Kuitunen, Ari Jäntti, Jukka Suhonen and Teija Aho. The aim of this work was to examine differences in paternal and maternal care in a double-brooded, monogamous species, the Treecreeper Certhia familiaris, in relation to food availability. As a measure of parental care, we recorded the hourly feeding activity of parents when the nestlings from their first and second breeding attempts were 7 and 12 days old. Feeding frequency of the first brood increased with the age of the nestlings and also with the brood size when 12 days old. While the feeding activities of the females were similar with respect to the first and second broods, the males were less active and failed to provide any food to their nestlings in 15 cases out of 28 second broods. In spite of this, the fledglings from the second broods were heavier than those in the first. Such a pattern of male behaviour was possible without being a disadvantage to the chicks because the food supply increased during the breeding season and the female could provide food for the young alone. Thus paternal care was particularly important in times of poor food supply, i.e. during the first brood, where the extent of these males' activity in feeding the 7-day-old nestlings was positively correlated with the average mass of the nestlings. Our results support the idea that the male of monogamous, altricial bird species often makes important contributions to raising the young, especially during periods when it is difficult for the female to do so alone. Males show flexibility in their pattern of parental care, and male Treecreepers change their contribution to the first and second broods within the same season.

The birds move from tree to tree, said to be maintaining an overall direction of travel. They may tend to be found on the more substantial trunks. The flight from tree to tree may involve quite acrobatic braking and swooping to land on the next tree. Title: Effects of male removal on female foraging behaviour in the Eurasian Treecreeper. Author: Aho, Teija ; Kuitunen, Markku ; Suhonen, Jukka ; Hakkari, Tomi ; Jäntti, Ari Behavioral Ecology and Sociobiology, 1997, Vol.41(1), pp.49-53
In old, spruce-dominated forests of central Finland, Eurasian Treecreepers Certhia familiaris divide their territories spatially during the breeding season. Females forage primarily on the upper parts of the tree trunks, while males use the lower parts of the tree trunks. In this study we removed males from eight territories in the early nestling period to see if the mate's absence would change the foraging patterns of the resident female. Widowed females foraged at lower heights, thus behaving more like paired males. These females also spent less time on each tree and on each foraging bout than did paired females. We conclude that male removal facilitated the change in a female's foraging niche and foraging time at the trees. Females may re-optimize their foraging site selection owing to the absence of dominant males and a consequent need to increase their parental care. Behavioral plasticity may be the mechanism of niche partitioning between the sexes in this species.

The adults have one complete moult after breeding, later in the summer. The juveniles have a partial moult, actually fairly quickly after fledging, retaining their wing feathers until the following year's moult.  

Craig Bron Bannog

A really lovely spot in the depths of the huge Glocaenog Forest, with great views of the surrounding hills, but sadly with relatively few birds! Another birder I met at the top of the hill, who was from Cyffylliog, mentioned some Crossbills he had heard going over the track earlier, which I had been too early for (!), and we didn't see anything from the viewpoint. Later I thought I might have heard, but not seen, Crossbills by the track on the way down. The hill is supposed to be a good site for a Great Grey Shrike (2012?) but there was no sign of it today. Perhaps this bird just didn't make it back this year. Nothing else at all was spotted for the whole of the 30 minutes that I was there - very quiet!

The details and the equipment of the CEH experiment at Craig Bron Bannog looked quite incomprehensible, although its principles were clear - what effect would the warming and drying of climate change have on moorland ecology and on moorland carbon sequestration!

Here is some frosty heather - definitely a sharp, but not bitter, morning.

This is the phone mast which occupies "pole position" on the hill, and presumably enables the track for access to the experiment at a reasonable cost! A nice bench looking South makes a really good lookout.

Driving around the whole forest later in the morning, quite a few Blackbirds, and a Robin, as I started the drive from the public house and along the Afon Alwen. As I got into the forest, and then past the West bit of the windfarm, there was one turbine with a broken blade lying on the ground. Later there were dozens of Fieldfares and Starlings on the sheep pastures by the Northerly section of the windfarm, with a flock of Chaffinches in the hedge by the next farm. There were Buzzards along the various roadways all day long. A quite large and strange bird flying straight and high over the forest - mainly white with some black, but definitely NOT a seagull - was seen from the car - a complete mystery! Possibly a domestic pigeon??

Lovely Leybourne

Walked slowly around the first part of the country park with Nain.

1 Greater Spotted Woodpecker, Blue Tits, Great Tits, Long-tailed Tits, Blackbirds, 1 Redwing, Magpies, Black-headed Gulls, Coot, Common Gulls, Herring Gulls, Tufted Duck, 1 Robin, 

A very still but chilly Reculver

Half a dozen mute Swan, about 600 Dark-bellied Brent Geese, 2 little Grebe, 1 little Egret, about 50 Common (?) Gulls, a dozen Herring Gulls, a score of Black-headed Gulls, one Great Black-backed Gull, about 30 Cormorant, 6 Grey Plover, 2 Ringed Plover, 30+ Redshank, 2 Curlew, half a dozen Turnstone, a score of Oystercatchers, a score of Carrion Crows, a Magpie, a pair of Stonechat, 3 Blackbirds.

It was so nice the see the pair of Stonechat, with good views, I do always like to see "monogamous" birds. The male is perhaps the same one as I saw here on the 27th, 3 days ago, in a howling gale along the seawall but quite a bit further to the West. Plumage features for this male were all OK for hibernans, with a deep russet and widely-spread chest patch, not too extensive a white collar, and a fairly buffy rump. I could see white wing bars when either bird flew, but more obviously in the male. The pair were on the grassy islands and seaward borders of the Coldharbour Lagoon, and I saw the male first, mainly perching, occasionally descending to the ground and back again. The female was generally quite close, once only a few metres away. It was possibly using lower perches on average than the male, and I couldn't keep track of it as well as the male.

Then a few minutes later either the same pair or a new one were on the beach between the Coldharbour Lagoon and the Outfall, causing me some considerable confusion! I think the male was on a seaweedy breakwater first, then on the beach with the female, then on a line of boulders. 

Icy Leybourne

Coot, Moorhen, Tufted Duck, Pochard, Mallard, Shoveller, Greylag Geese, Grey Heron, Cormorant, Great Crested Grebe, Little Grebe, Black-headed Gull, Common Gull, Larus canus, Herring Gull, Carrion Crow, Magpie, Starling, Wren, Redwing, Blackbird, Robin, 1 Blue Tit, 1 Long-tailed Tit.

Cracking Cliffe with a great Stonechat!

A really great walk around Cliffe with great birds including Green Woodpecker, Stonechat, a dozen (+) Goldfinch, a dozen Fieldfares, Blackbirds, 3 Chaffinch, Pochard, Pintail, Wigeon, Mallard, Shoveller, Teal, Shelduck, Coot, Moorhen, Greylag Geese, Little Grebe, Great Crested Grebe, Herring Gull, 2(+) Grey Heron, 2 Little Egret,

Stonechats are rounder, dumpier birds with shorter wings than the quite similar but migratory Whinchat, Saxicola rubetra. The Stonechat that I saw, Saxicola torquata hibernans, or perhaps more modernly, Saxicola rubicola hibernans, was a beautiful male bird, with gorgeous colours in the sun. The face was very dark, just visibly darker in fact than the cap which was more a darker continuation of the brown streaky back. The throat was very dark, contrasting well with the half collar, which seemed narrower than the book pictures, but didn't seem to extend noticeably further back towards the rear of the neck, so being fairly typical of the normal western forms of this polytypic Eurasian (or bitypic European) species. The white wing-bar was there on the dark wing, but not noticeably wider or more obvious than predicted. The front warm pink was well-spread, again fairly characteristic of the western form. I didn't see the rump, but didn't mark it as very different from the back colours, definitely no obvious large white patch there! All I could see on the tail was the flicking, but it seemed dark to me, again as expected.

European [continental] Stonechats S. torquata rubicola, or S. rubicola rubicola are virtually indistinguishable from the British/Atlantic race S. torquata hibernans or S. rubicola hibernans. The two subspecies are almost a cline with the intergrades at the boundary being indistinguishable, although the extreme British birds are particularly dark with reduced white patches, while the more Eastern birds of the European subspecies are very pale with obvious white patches, close to the Siberian type. Siberian-type or Eastern Stonechats, Saxicola [torquata/maurus?] maurus/stejnegera are occasionally seen in the autumn on the coast of Kent, but are apparently rare. (N.B. maurus is used here in preference to maura as listed in BWP).

There have been quite a few reports of the British/Atlantic forms of Stonechats on the Kent coast this year, as in previous winters. The wintering numbers have increased somewhat in Kent since the 70's, sometimes inland along the Stour as well as around the coast, with occasional counts of 15 at favoured sites such as Cliffe being recorded, according to "Birds of Kent". However counts I see on the KOS website seem generally to be in the [smaller] single figures, typically at Cliffe, Elmley, Swale, Samphire Hoe and Dungeness, and the KBR 2012 suggests a county-wide over-wintering total in the mid-30's. A handful of pairs (averaging about 4) also nest in favoured habitats along the coast such as at Dover.

Kent records indicate that some degree of autumn migration of "hibernans" Stonechats is usually obvious, but spring migration is rarely noticeable - perhaps the birds migrate back along a different flyway? Breeding is occasionally proved around the Kentish coast, in very small numbers. I get the impression that winter numbers are higher than summer numbers in this county.

The UK population probably declined after Victorian times due to habitat loss, but seems to fluctuate strongly. In 1961 Magee wrote a well researched report investigating the overall decline in populations over the century to that date. He showed how cold winters, particularly those involving long periods of snow or hard frost caused intermittent but great losses, particularly in inland areas, but populations generally recovered given milder conditions, recolonising coastal locations and then spreading inland. Ironic that the winter of 62/3 was to follow immediately after publication of this paper. The reliance on coastal areas for the survival of the core population is also suggested that in the more "Atlantic" conditions of Ireland, there is a greater tendency to regularly breed inland, so that territories are more evenly spread across the landmass as a whole. However Magee also showed an overall downward trend in numbers over the longer term, due to agricultural intensification, forestry planting and maturity, as well as [I imagine] human population growth and resulting disturbance. Populations recovered again after 62/3 and then rose significantly again between the 1990s and 2010, changing the species' status from amber to green, only for numbers to be halved between 2009 and 2010 from its peak, presumably by the harsh winter weather that winter. However although it is classified as a resident, surely there are more birds seen generally in the summer than in the winter? Might this imply some degree of migration? Perhaps Stonechats try to "spread the risk". Kent may be an exception, where Stonechats are easier to find in winter than in summer.

Food is of insects and other invertebrates throughout the year, with some seed and blackberries taken at times, and occasionally even small fish or lizards. The birds may often dart down from perches, often roughly a metre high, catching prey immediately or after a bit of hopping, but will also take insects in flight (note genetic link to flycatchers), off leaf-surfaces, off the surface of water, picked off surfaces while hovering, or picked up after a "hover-chase". May return to the same perch or a different one. adults seem to like caterpillars and shield-bugs!

From BTO records, Stonechats can breed from a year old onwards, with the record for longevity being a bird nearly five years old.  They can produce several broods a year, from April onwards, with 5 - 6 eggs per batch. The eggs take about a fortnight to hatch and the young take about another fortnight to fledge. Stonechats are generally monogamous and both parents do take care of the chicks, feeding and protecting.

It is generally held that Stonechats are generally found to be more coastal and lowland, 9 out of 10 Stonechat nests being below 125 m asl, while Whinchats are rather more upland in distribution. According to the Welsh Chat Survey of 2012 - 2013, both Stonechat and Whinchat were associated with extensively managed, non-intensive, unimproved, habitats, and not with linear features such as hedges. Both Stonechats and Whinchats forage from prominent features and were associated with scrub or bracken but Stonechats were also associated with coarser herbaceous cover and Whinchats with semi-natural grassland and damp areas. Whinchats, which are migratory, have had a population collapse over the years - and natural while not too heavily grazed grassland is increasingly rare. Stonechats did seem to be doing quite well, until the terrible losses over the winter of 2009 - 2010 mentioned earlier.

The calls are interesting, particularly of the parents. Breeding Stonechats (Saxicola torquata) made mixed sequences of two calls when a human intruder entered territories. ‘whits’ are modulated notes with a small frequency range, and in laboratory tests caused nestlings to stop begging. ‘chacks’ cover a wide range of frequencies, and in the field were combined with flights made so as to distract an intruder from the nest. On average male and female call-rates were similar, but varied greatly according to the intruder's distance from the nest, and at different stages of the nesting cycle. Rates increased rapidly after hatching, and this correlated most closely with the cumulative total of parents' visits to feed nestlings. This suggests that the level of defence may be adjusted to the value of the offspring to their parents. Call-rates declined about one week after fledging. A smaller peak by some pairs at the start of incubation was apparently related to probable poor condition after a previous breeding attempt, and after laying large clutches. Rates of 'whits' were higher at nests with larger broods, up to an asymptote, but rates of 'chacks' were independent of brood size. Birds suffering nest-predation showed lower call-rates before the event than equivalent successful birds, suggesting that the calls do reduce the risk of predation. Parental investment in nest defence by Stonechats (Saxicola torquata). Animal Behaviour, Volume 28, Issue 2, May 1980, Pages 604-619 P.W. Greig-Smith.

The birds tend to be seen as either singles, or more commonly as pairs, in the winter, not generally as groups. The pairs may not be the breeding pairs for the next summer, subject to change particularly when migrant birds arrive in the spring. Males tend to be more noticed as singles than the females. Pairs which do not disperse after breeding may defend the same [albeit often larger in the UK, maybe smaller in Spain] territories over the winter.

Breeding territories vary between 0.5 and 4 ha in size. Males may sing and display from higher than normal perches. The white wing coverts tend to be displayed, while the male stands erect, with the head held up, and there are also intermittent singing display flights at 10 - 25 m. lasting for up to 15 s, slow and jerky, with shallow wing-beats and perhaps brief hovering. The bird may rise and fall while hovering. The tail and legs are held down and the white on the neck, wing coverts and rump is very obvious. There may be a lot of tail flicking when a male lands after a display flight. Males may fly back and forward over the female, hover over her, chase her violently, fan his tail or bow to her. The last two are part of the male pre-copulation display, with the female reciprocating by crouching and shivering, with quiet calls. Displays and singing of paired males may continue over the breeding season. Unpaired males may sing frequently near to females for the first half of the season, but then tend to depart.

Nests of grass and lining are placed at bases of bushes, in different positions for successive broods. Year to year fidelity of territories apparently low, perhaps due to mortality. Generally monogamous, although mates may be interchanged between seasons [on spring stopovers for migratory birds??], or even between individual broods. In Jersey, existing pairs broke down over a short period as the migrant birds arrived. In the breeding season other species of small birds may congregate around the individual watchful Stonechats.

The female along broods the eggs for about a fortnight, with the male visiting her with food. After the eggs hatch, the female continues to brood the blind fairly helpless nestlings for about five days until their eyes open, both parents feeding the young. In large broods the nestlings compete for the rear of the nest where they can lie on top of the ones at the front, to get priority for food. The young then may move to hiding places about 5 m. away from the nest for a few days and then start to follow parents, finally fledging after about 12 - 13 days after hatching. Broods follow in quick succession, 2 broods for migrants, perhaps 3 for residents. The high potential productivity of the early season starts perhaps explains the terrible risks the birds take by overwintering, and the occasional and irregular but ultimately inevitable very heavy winter losses.

Once juveniles fledge, they may leave voluntarily or at the insistence of the male parent when the next brood hatches, and then may may move around the parental and neighbouring breeding territories in groups of 4 - 5. They chase and supplant each other, about 2 m. or more apart.

A cracking male bird, for sure! I wonder if there was a female there as well, that I just didn't spot?