Ringing: April 2014
Wednesday 30th April
One of John’s groups was booked-in today and as usual the ringers rallied in good numbers to ensure that the visitors had a very enjoyable and instructive day. To ensure success nets were put up at 6.30 am and as birds are fairly few at the moment we put up an extra five nets and the day did not end until nearly 4 pm.
23 birds were processed in total including two new species for the year – 2 Common whitethroats and 1 Lesser whitethroat. As well as these, other species ringed were Chiffchaff, Collared dove, Greenfinch, Sparrowhawk (a new bird for Sarah) and 2 Yellowhammers.
Apart from thoroughly enjoying the ringing session the group had a great walk with highlights including the many Green-winged orchids, extremely rare Heath dog violets, Blue-winged teal, Stonechat, Wheatear, Yellow wagtail, Corn bunting, Whimbrel, Bar-tailed godwit, lots of singing warblers and the newly hatched Lapwing chicks on the scrape.
Participants, all from West Kent, said how much they appreciated what was arranged for them and how much they enjoyed their day at the Observatory – what a great way of enhancing and spreading the reputation of SBBOT and raising funds. Well done everbody!
Tuesday 29th April
Although only a few birds today we did ring a first for the year – a male Firecrest. Other new birds were a Stock dove and a Blackcap. A re-trapped male Chaffinch was first ringed by Cally as a young bird in September 2010, so is now 4 years old and a male Reed bunting is now looking very smart at the beginning of the breeding season.
REED BUNTING Reed buntings moult their head feathers once a year towards the end of the summer but are still able to change their plumage considerably ready for the spring. The males head will look quite patchy grey and brown after the moult and as the autumn and winter progress the fine grey/brown tips to the otherwise black head feathers naturally wear off revealing the black feathers underneath, so that by spring their heads look ‘smart’ and usually completely black. A few grey tips are present on the warn head feathers of today’s bird in the photograph.
Anecdotally we were discussing the fact that we seem to catch more male than female Reed buntings and this was confirmed when Steve checked the details on the computer. In total we have processed 2,448 Reed buntings over the years:
Friday 25th April
An unexpectedly late Redwing was ringed today. Redwings migrate in late summer/early autumn from Iceland, some of them moving through the UK and stopping off briefly on their way to Portugal, Spain and France where they spend the winter. The Icelandic birds are from a separate race, coburni and are slightly larger, darker and more boldly marked than those from Fenno-scandia, which winter in Britain. This bird was a young female with a noticeable brood patch, and although impossible to say, may possibly be winging its way back to Iceland ready to breed in the very few native birch forests or scattered pine plantations there.
On corvids, a male Jackdaw was processed today which had been ringed here on 5th March 2011 as an adult, so is at least 5 years old and a female Magpie first ringed on 9th June 2010 and now at least 5 years old also.
Wednesday 23rd April 2014
Despite almost perfect conditions it was another quiet day. New for the year was a Reed Warbler caught in the side-Haven net. Other birds caught included a Stock Dove, a Chaffinch and retrapped Moorhen, Dunnock, Greenfinch and Chaffinch.
Of note – the retrapped Moorhen was caught in a box trap at the Observatory pond, (this bird was originally ringed by Graham as a 5M (young male) in early March 2012, also caught using a box trap at the obs pond). The retrapped Chaffinch was ringed as a 3J (juvenile) in 2012 and was originally caught in the Whitehouse by Sue Smith – now a stonking adult male.
During a very quiet period during the day, Pete showed Becky how to mend the side strings on a 40 foot mist net. Nets are expensive to replace, so during quiet times such as these we plan to do some more.
Stock doves are very common, widespread birds but are often overlooked, probably because of their similar size to Feral pigeons. After a decline during the use of organochlorine seed-dressings in the 1950s, populations have increased to a current estimate of about a quarter of a million pairs. They are found in mixed farmland and nest in woodland and hedgerow tree holes, nest boxes and cavities in buildings and are numerous around The Observatory, so make a point of looking out for them – they are very attractive birds.
Stock dove plumage is mostly blue-grey with a beautiful large green iridescent neck patch and few other markings other than small black wing patches. In flight they show grey underwings which are mostly white in Feral pigeon and from above the extended black wingtips and black edging along the entire hind wing is very noticeable. They are smaller than Woodpigeons, which is noticeable in mixed flocks and their faster ‘flicking’ flight can be useful to look for.
Friday 18th April
A very quiet day with only three new birds ringed – a Wren, a Blackbird and a new species for the year, a Rook. A re-trapped female Chaffinch ringed as a 3F (young female of the year) on 14th September 2012, now a 6F (adult female) was found to have a brood patch, indicating a local bird in the process of breeding.
Rook Corvus frugilegus – please see accompanying photographs.
The new BTO Atlas shows that the distribution and population of Rooks in Britain remains more or less unchanged with a breeding population of almost 1M pairs, making it one of our most numerous species. They are to be seen in spring noisily displaying around their colonies or feeding in large flocks on grassland.
They are birds of farmland and especially pastures which is why we see so many around the Observatory, often with Jackdaws at this time of year. They are omnivorous eating invertebrates, cereal grain, small vertebrates and carrion, but at the moment earthworms are an important part of their diet.
Have a look at the two photographs of a bird photographed this week using its tongue to relocate an earthworm from its bill tip back towards the oesophagus. All birds have a well-developed tongue, varying in shape from family to family. The tongue usually takes up the space inside the lower mandible and is as long as the bill. In Passerines such as the Rook the tongue is hinged at the base and will have backward pointing barbs or projections on the surface to enable the bird to manipulate food back into the mouth. Some species locate and even gather food using the tip of the tongue.
Monday 14th, Tuesday 15th & Wednesday 16th April
Of the 3 Blackcaps ringed on Monday two were females. The males have been singing in established territories for some days now and females are only just arriving to take their pick of territorial males. Our first two females of the year have been ringed today- 9 days after our first male birds on 5th April, so following the usual arrival pattern.
On Tuesday a Chiffchaff was our only new bird ringed but we did process an interesting re-trapped Meadow Pipit that was ringed by Pete Findley last September, when large numbers were on the move. It is interesting that this bird has returned to us again the following spring. This bird ringed here in September was probably part of a very visible, mainly diurnal, autumn passage of which some are birds moving from upland to lowland areas and some stay on in Britain during the winter. Ring recoveries show that some British breeding birds spend the winter in SW France and the N & W of the Iberian Peninsula.
Another Chiffchaff and a Robin were our only new birds for Wednesday. With species such as these where there is no sexual dimorphism (no obvious difference in plumage between male and female), we were able to sex the Chiffchaff as a male because we were able to see a cloacal protuberance and the Robin as a female due to the presence of a brood patch. More on this another time…..
Sunday 13th April
Another Chiffchaff today plus two nice species – Jay and Bullfinch. Two new Jays were ringed and 2 Bullfinches were caught together in the same net – a male and female, so probably a pair. The female was re-trapped having been ringed by Eugene at the Observatory last year aged 5 – a young bird. The male was a 5 – hatched last year. Unusually, Bullfinches do seem to stay together as a pair throughout the year.
Thursday 10th & Friday 11th April
Chiffchaffs, Blackcaps and Willow Warblers are still on the move, but not many birds were ringed. On Thursday new birds were a Blue Tit, 2 Blackcaps, 2 Long-tailed Tits, 2 Willow Warblers and 3 Chiffchaffs, and on Friday 2 Blackcaps, a Chiffchaff and a Collared Dove.
Willow Warbler Once an extremely common and widespread breeding species, many of us will have noticed an enormous decline in the population of Willow Warblers in South East England in recent years. This started in the late 1980s with a sudden decline in adult survival in southern Britain whilst there was no evidence of this happening in the North.
The new BTO Atlas now notes that breeding densities remain low in much of southern, central and eastern England and monitoring data shows a 28% decline in England during 1995-2010, contrasting with a 33% increase in Scotland and a 64% increase in the Republic of Ireland during 1998-2010.
Changing climatic conditions, the quality of breeding habitat and environmental changes in Africa are considered to be driving the changes in abundance at the regional scale in this long-distance migrant. If you check the Willow Warbler distribution map in your field guide you will notice that this species does have a markedly northern distribution in Europe, possibly with many breeding sites linked to Birch scrub.
Tuesday 8th & Wednesday 9th April 2014
New summer migrants are arriving thick and fast and ringers’ contributions were a Willow Warbler and 3 male Blackcaps ringed on Tuesday and another Willow Warbler, 3 Wheatears and a Tree Pipit on Wednesday. Other newly ringed birds for the two days ware Chaffinch, Blue Tit and yet another Moorhen, this time caught in the Heligoland. On drives to and from the beach on Wednesday a Corn Bunting, a Common Redstart and 4 Common Whitethroats were heard or seen and butterflies included Peacocks, Small Tortoiseshells, Small Whites and Speckled Woods.
Wheatear and Tree Pipit were ‘ringing ticks’ for the year. Two of the Wheatears were from Prince’s and the other from between Royal Cinque Ports and the Sailing Club.
Tree Pipits can be tricky to identify, but in the hand one of the interesting differences is in the length and shape of the hind claw. This can be seen in the following two photographs, comparing this current Tree Pipit with a Meadow Pipit photographed previously. Most of the pipits and larks have long, usually curved or partially curved hind claws so it is interesting to think about why there is a big difference between these two, both of them ground-nesting species. Having hit on the possible answer, how then do the majority use their long hind claws? The ‘experts’ might know and I have a theory – what do you think? E-mails to firstname.lastname@example.org (please make the SUBJECT – pipits & larks.)
Friday 4th and Saturday 5th April
Both quiet days but with some new birds – on Friday a Blackbird, a Chaffinch, 2 Reed Buntings and another Yellowhammer. There is obviously a small movement of this species taking place.
On Saturday new birds were a Blue Tit, a female Bullfinch (an unusual species for us) plus three warblers – a Chiffchaff, a Cetti’s Warbler (we catch hardly more than a couple each year) and 3 male Blackcaps. The latter always follow soon after the Chiffchaffs as some of the earliest of the summer visitors and males arrive before the females to enable them to set up territories. New for the year was a singing Willow Warbler and two butterflies, Speckled Wood and Small White.
Cetti’s Warblers first bred in the UK in Kent, in 1973. Since then their colonisation has spread strongly across England and Wales. They remain with us throughout the year and because of their loud and explosive song males are easily located by fieldworkers.
By the 1988-91 BTO Breeding Atlas Cetti’s Warbler was recorded in 89 10-km squares and this despite substantial losses in Kent and East Anglia during severe winter weather in the mid 1980s. They seem to recover rapidly and by 1996 there were almost 600 territories in Britain and numbers have risen exponentially, recently doubling in periods of four to seven years, and now total at least 1,900 territories. The colonisation in Britain was part of a major expansion northwards from the Mediterranean in France during the 20th century.
Cetti’s Warbler details from the BIRD ATLAS 2007-11 a recent BTO publication.
Monday 31st March & Tuesday 1st April
Two very quiet days with very few birds ringed but brightened on Tuesday by 3 more male Yellowhammers and a very smart adult Moorhen from the pond – a new species for the year.
A few late Chiffchaffs were moving through last week but most had already arrived in breeding territories throughout the country, with the males singing loudly and persistently. Approximately 2 million of them would have crossed The Channel from the Continent over a few nights at the beginning of the third week of March to breed in the UK, with even more on their way as passage migrants to Scandinavia!
The main migration of Willow Warblers will be evident soon, although a few have already arrived. Always difficult to separate in the field from Chiffchaffs, the song and call are distinctive but visually there are problems with individuals with variable leg colours, superciliums and general colouring. Feeding Chiffchaffs ‘flick’ their wings and tail whilst on the move, whereas Willow Warblers do not – a good point to look out for.
In the hand we can look at the wing formula and with Chiffchaffs and Willow Warblers they are different. The chiffchaff, as a fairly short distance migrant, has shorter more rounded wings and the Willow Warbler, flying further has longer wings. Also clear is where the outer web of a primary feather narrows abruptly towards the tip, when it is said to be ‘emarginated’. Chiffchaffs have the 3rd, 4th, 5th and 6th primaries emarginated and Willow Warblers only the 3rd, 4th and 5th , which is clearly seen and shows well in the photographs.