Ringing: July 2014
Thursday 31st July
After a pretty exhausting day with just a few of us setting up in the maize yesterday we had a trial run ringing this morning, not starting until six-thirty but with migration just under way we ringed 15 Sedge warblers, 7 Reed warblers and a Whitethroat. Our totals soared later when we put nets up in the Oasis and the Side Haven where we caught 51 House martins, a Swallow and a Sand martin, a Great-spotted woodpecker, Greenfinch and Blue tit. Great! – Migrant birds are now on the move and we are anticipating a busy autumn of ringing to come. The photograph in the hand taken today,is of an adult Sedge warbler showing worn plumage, typical at this time of year.
SEDGE WARBLERSare always attracted to fields of maize along with Reed warblers and others, the tall crop must be reminiscent of the phragmites reed-beds that they are used to. About 250,000 pairs of Sedge warblers breed in Britain building their nests deep in the base of dense vegetation in many types of wetland. At the end of July they commence their migration south into Africa but before they go they search out reed-beds with high infestations of Plum-reed aphids in southern England and north-west France. Feeding on these aphids and many other insect species they lay down fat in various body cavities and subcutaneously (under the skin), so much so that prior to migration they will on average put on an additional 50% of their body weight and some will almost double their weight. With this store of fuel on board they undertake rapid, long-haul southerly journeys. There are few autumn ring recoveries of Sedge warblers in France or Spainas they have few if any feeding stops through southern France,Iberia, North Africa or the Sahara. There have been more than 4,000 ring recoveries of this species, 80% of which are by ringers in West Africa, south of the Sahara where they spend the winter in Senegal, Mali and Ghana. Ringing has told us so much about this trans-Saharan migrant that we know that birds from Ireland and western Britain winter in Senegal while those from eastern Britain are found in Senegal eastwards through Mali and Ghana.
Monday 28th, Tuesday 29th & Wednesday 30th July
A few more warblers plus some hirundines on the move. New birds – 4 Reed warblers, 2 Chiffchaffs, 12 House martins, a Swallow, plus a House sparrow, Chaffinch, 2 Robins, Greenfinch a Dunnock plus 10 young Great tits from two families feeding togetherbehind the Ringing room. They must have bred nearby and paid us a visit for the first time. With our catch of 12 House martins it seems that they are young birds gathering along the coast in pre-migration flocks.
HOUSE MARTINS, as Jim Flegg says in his book ‘Time to Fly’, are the British enigma when it comes to bird migration. We know them so well here in the UK as familiar breeding birds and summer visitors. However it is most surprising that there are hardly any ring recoveries of British birds anywhere in Africa and indeed there are only scant observations of House martins by bird watchers in this huge continent, so where do they go? With many more birdwatchers and ringers operating in Africa, more ringing and perhaps the use of geo-locators and even smaller radio transmitters the answer may soon be revealed. It was only discovered just over two years ago by fitting radio transmitters to British Cuckoos that this iconic species winters in the huge, remote and unfriendly Republic of Congo and sometimes northern Angola.
FLAT FLIES are ectoparasites that live on the ‘outside’ of birds, on their skin and in their plumage. They occur on a number of species but we always notice that they are most prolific on hirundines. The photograph is of one that has jumped off a House martin onto John’s hand. They are tough, leathery, flattened blood-feeding flies with well-developed claws and an ability to move very rapidly in any direction. This species is free-flying and able to move between hosts but must be fast and well adapted to slip between the plumage as birds preen with their bills.
Friday 25th, Saturday 26th & Sunday 27th July
New birds were 4 Reed warblers, 3 Willow warblers, a Whitethroat and a Sedge and Garden warbler, 2 Long-tailed tits, 2 Blackbirds, and single Swallow,Robin, Wren, House sparrow and Green woodpecker. Sedge warbler and Garden warbler were new for the year and even though this was just a short list of warblers it is an indication of a trickle of birds starting their migration.
Wednesday 23rd July
22 new birds included 6 House Sparrows, 4 Greenfinches, 3 Blackbirds, 2 Wrens, 2 Robins, 2 Blue Tits, 2 Whitethroats and a Green Woodpecker. Too bright and windy to entice more hirundines to the nets. This young Great Tit is one of many young birds we have been ringing over the past few weeks.
Tuesday 22nd July Forsaking the chance of catching more hirundines, we decided on more ringing maintenance today with the usual few taking the tops off the trees on one side of the Oasis to encourage birds into the ringing area and closer to the nets. Sarah, Becky, Pete, Steve and John were pretty exhausted after a long day in the heat.
Monday 21st July
A good catch of 32 new birds ringed today with hirundines featuring heavily – 20 Swallows, 3 Sand Martins and 2 House Martins (the last two species were new for the year). All of the Swallows and Sand Martins and one of the House Martins were young birds.
The photograph of the young Sand Martin shows the distinctive pale scalloping on the contour feathers typical of a young bird, and this individual was particularly small. Young and adult House Martins are shown below with the young bird looking ‘greyer’ with the tertials broadly tipped white. The adult bird has much whiter undersides and a fabulous blue iridescence.
Sunday 20th July
18 new birds were ringed today with the usual mix of resident species plus 1 Reed Warbler, 1 Chiffchaff, 2 Blackcaps and 5 Swallows. These are the first Swallows of the autumn and are young birds, probably local or birds gathering at nearby roosts prior to migrating later. The majority of Swallows breeding in Britain and Ireland start there push south through the country in August but with only a few exceptions that cross the Channel in late August, they do not leave us on their southerly migration routes until September and into October.
Swallows are generally easy to catch and are ringed either as ‘pulli’ (nestlings), young or adults at roosts or generally in mist nets. Luckily there are many ringers active in South Africa particularly operating around the huge reed-beds where vast numbers spend the winter. This is the ultimate destination of our British birds, where many ringed birds have been recovered. Half of the recoveries of British ringed Swallows are birds re-caught by ringers (as opposed to birds found dead) – a very high percentage and it is now known that most of our birds are to be found wintering in Cape Province and Kwazulu Natal.
Friday 18th July
10 new birds were processed today – 2 Chaffinches and singles of Blackcap, Whitethroat, Chiffchaff, Reed Warbler, Robin, Blackbird, Greenfinch and finally a juvenile Black Redstart. This was a first for Graham and he will have been delighted that the heligoland had been cleared only a few days before and attracted this exciting bird.
Black Redstarts are regular but not very numerous passage migrants at Sandwich Bay and this is the first of this species ringed here since 2008. It is also the first to be caught in July and as another juvenile bird and an adult were seen today, this early occurrence may possibly indicate that they were fairly local breeding birds. The Black Redstart is a scarce breeding and winter visitor in Kent and a regular passage migrant. Most of the early colonists were attracted, as in other UK locations, by the bombed urban sites along the Thames and in Dover during and after World War 2. Pairs were also breeding on the chalk cliffs and the first recorded nesting in our County was at Ringwould in 1930. Since 1940 Black Redstart has been found to breed annually around the Kent coast in varying numbers and certainly every year between Deal and Dungeness, where current regular sites are at Samphire Hoe and around Dungeness Bird Observatory. Other less regularly used locations over the past 70 years have been between Dartford in the north-west, eastwards to and around Thanet.
Thursday 17th July
17 new birds today – 4 Great Tits, 3 Reed Warblers, 2 Whitethroats, 2 Blackcaps, 2 Robins, a Chiffchaff, Chaffinch, Dunnock and Wren. After ringing here for more than a year this was Becky’s first Wren – the Observatory is now better off by her ‘new species’ £1 donation. We are starting to see more warblers on the move and many of these will be birds that have bred locally, but some must be individuals starting their migration. The photograph shows the wing detail of two Reed Warblers. The fairly new, crisp feathers on the wing of the juvenile above contrast with the old worn primaries and coverts of the adult below, an obvious feature when ageing this species at the moment.
Wednesday 16th July
Ringing resumed again today with 40 birds processed – 31 new birds and 9 re-traps. New birds were 8 Great Tits, 6 Chaffinches, 3 Whitethroats, 3 Blackcaps, 3 Robins, 2 House Sparrows, 2 Collared Doves, a Dunnock, Song Thrush, Starling and Greenfinch. A large proportion of these continue to be young birds.
Tuesday 15th July
Wet and windy weather has frustrated ringing for several days but on Saturday and today a few of us worked hard in the heligoland to clear much of the Willow and Alder, to open it up and improve the habitat. The idea being to encourage more birds along The Haven and into the catching area. Lo and behold a Black Redstart was tempted in on Friday 18th and was successfully processed. Hard work by a few in very hot and humid conditions was rewarded!
Wednesday 9th July
8 new birds for the day – 2 Great Tits, 2 Dunnocks, a Chaffinch, Collared Dove, Greenfinch and a Great-spotted Woodpecker.
It is good for a change to record a species showing both a recent population increase and a range expansion. The UK population of Great-spotted Woodpeckers increased by 408% during 1967-2010 and not only that, they colonised Northern Ireland for the first time in 2006 and the Republic of Ireland in 2009. Another highly sedentary species, Great-spotted Woodpeckers were absent from Ireland along with other woodpeckers until then, when the huge population increase in the rest of the UK must have pushed a few individuals across the Irish Sea, which had proved to be a barrier in the past. Ireland has 20% fewer breeding bird species than the British mainland, the reason for which almost certainly goes back to a time after the Ice Age when sea levels were rising and both Britain and Ireland were still attached to the Continent. The Irish Sea flooded through first making Ireland an island many hundreds of years before the same thing happened down the North Sea and when the Channel was formed. As the climate was warming throughout this time, there were fewer animal, bird and plant species in Western Europe when Ireland went off as an island than when Britain became marooned. For the same reason of course, Ireland has no snakes.
Friday 4th July
15 new birds ringed today – 2 Wrens, 2 Robins, 2 Blackcaps, 2 Blackbirds, 2 Dunnocks, a Great tit, Chaffinch, Blue tit, Collared dove and last but not least a Treecreeper.
The Treecreeper is oneof the UK’s most sedentary birds (a species that moves very little if at all even between the seasons) with a distribution mirroring its mostly woodland habitat. It suffered a population decline of 18% during 1970 – 2010 but seems to have stabilised subsequently. With no mature areas of woodland or hedgerow trees around The Observatory, this is an unusual species for us to see and the ringers only catch one or two each year. They are usually young birds moving off to find a territory of their own at the end of the breeding season.
The photograph of the Treecreeper in the hand shows several features – the long, thin, down-curved bill is designed for probing for insects and the thick shafts on the tail feathers stiffen the tail allowing the bird to ‘prop’ itself away from the bark when moving around and thus avoiding wear on the feathers on its underside. The beautiful patterning on the back is great camouflage with the surrounding tree bark and provides disruptive markings to the eyes of a predator.
The photograph of the Treecreeper on the Silver birch, carrying food to its young, shows some of these features again, especially the use of the stiff tail feathers and also the very long toes and hind claws. The tiny, twiggy nest is often built in a split in the bark of a tree or in a small cavity where they raise 5-6 young.
Tuesday 1st & Wednesday 2nd July
RINGED PLOVERS On Tuesday we checked the beach along the Princes stretch again for breeding Ringed plovers and two nests, one of 4 eggs and the other of 3 eggs were located. Last year four nests, each with four eggs were found and none of them survived beyond the egg stage. When the tide is in there is currently only a very narrow strip of beach for this very vulnerable species to find enough of a mix of shingle and sand to make a scrape and not be disturbed. Tragically on this important site there are many ways that predation by foxes, crows or others plus continuous human disturbance can happen. At one time on Tuesday we counted twenty one dogs off the lead.
Last year we ringed 7 adult Ringed plovers and this year it has only been possible to ring two. We managed to get good photographs of one of the other adults which was already ringed and read the number as NW10649. Great news as this female was ringed by John B on 26th June last year as an adult from one of the four nests, indicating that she has returned to the site to breed again. How many years has she been returning to Sandwich Bay each spring? If we can locate her or others again in 2015 and beyond we may start to build up a picture.
Britain supports a breeding population of only 5,300 pairs of Ringed plovers which declined by 37% between 1984-2007. Unfortunately little is known about their movements or winter range. Ring recoveries do show some general trends, however, with birds from southern and eastern England tending to move southwest to Brittany, Ireland and the West Country.
Later on Tuesday we cleared the very over-grown net rides in The Whitehouse and a start was made on removing the old 40’ boardwalk across The Haven, in preparation for constructing a new one. Other new birds ringed on Wednesday were 3 Chaffinches, 3 Dunnocks, 6 Starlings and a Goldfinch. Large flocks of noisy young Starlings are now a feature around The Bay and they are currently undergoing their post-juvenile moult which can sometimes be seen very obviously on individual birds at close quarters. In November Starling bills start to change from black to yellow and they can be sexed easily, as males show a pale blue patch at the base of the bill and females pink/buff. Another point in sexual dimorphism within Starlings is that males have a dark iris around the pupil and females a very pale iris. The photograph shows a male and female together and the eye detail is clear along with obvious dark adult feathers appearing as wing coverts and body feathers.