IntroductionThis report aims to give a brief account of the activities and results of ringing birds at Marston Sewage Treatment Works for the twenty-five years covering the period 1984 to 2008. Ringing birds was first undertaken by Gordon Priestley, who continues to catch and ring birds on the site, along with Alan Ball and Keith Bowden on a regular basis, and with other ringers from time to time.
During the first ten years, catching and ringing of birds was mainly undertaken on the grass plots and was mainly restricted to wader species, but numbers of waders have decreased when grazing sheep were taken off the plots in the late eighties. Since the mid nineties ringing activities began in the main treatment works area where many bird species congregate attracted to the insects originating from the treatment processes particularly in early Spring during periods of cold weather.
The creation of a wader scrape and the creation of a permanent reed-bed on the plots has increased the habitat and attracted additional species.
Ringing involves the careful catching of birds and then fitting a tiny uniquely numbered ring with a return address so that any subsequent ‘finder’ can report the find. All rings used in Britain contain the British Museum of Natural History’s address in London, which is internationally recognised around the world.
Bird ringing can provide a useful insight into the number of each species present, together with such useful information as longevity, causes of mortality, movement and migration patterns etc. This report includes a list of the numbers of birds ringed each year, together with a full list of movement details resulting from the ringing to date.
Acknowledgements
We are greatly indebted to Anglian Water for allowing access to the various areas at Marston Sewage Treatment Works and, in particular, to originally Chris Liesack, then Dave Key and most recently Alan Bee, at the works for continued permission on a day to day basis.
The assistance of other ringers and helpers is also acknowledged.
We would like to thank Andrew P Chick for providing the photographs on the front cover and Alan Ball for providing the other photographs used in this report.
Alan Ball and Keith Bowden – February 2009
Twenty Five years of Bird-ringing at
Marston Sewage Treatment Works
1984 - 2008
Contents
Section Page
Introduction 1
Acknowledgements 1
Contents 2
Birds Caught and Ringed 3
Bird Movements 4
Appendices
1 – Number of Birds Ringed 5
2 – Map of Overseas Recoveries 8
3 – Detailed Bird Controls and Recoveries 9
4 – Fact-Sheet – Why Ring Birds ? 20
5 – Photographs of some of the birds caught 22
Birds caught and ringed at Marston STWGeneralIn the twenty-five years from 1984 to 2008, some 16441 birds of 97 species have been ringed at Marston STW. The diversity of species is quite impressive for an inland site. Over approximately the same period between the years 1980 – 2000, Alexander Lees recorded some 162 species in his report ‘The Birds of Marston STW 1980 – 2000’ which illustrates the bird potential for this important site.
A full list of birds ringed for each year follows in Appendix 1. (pages 5-7)
The Grass PlotsSome birds are caught on the grass plots, particularly when flooded, and usually at night when waders and wildfowl are quite active, and the nets are less visible, enabling birds to be caught more easily. Over a thousand waders of twenty-two species have been caught and ringed, which illustrates the importance of this inland site. Seventy-two duck of 4 species have also been ringed, but catching wildfowl is particularly difficult, except for the smaller species such as Teal. The commonest wader species caught are Snipe and Lapwing, and although small numbers breed at Marston, the vast majority occur on passage mainly in autumn. Eighty-two Ruff, a fairly scarce British migrant have also been ringed, but the ‘best’ wader caught so far was a Pectoral Sandpiper in 1989. Unlike the other waders at Marston which breed in Northern Europe, the Pectoral Sandpiper is an American species and is a quite rare, but annual, visitor to Britain. Only about 60 have been ringed in Britain and this one provided the first British-ringed Pectoral Sandpiper recovery when it was subsequently recorded in Hertfordshire. Curlew have been caught in varying numbers throughout the period and two of the ones caught at Marston provided both the longest lived British-ringed Curlew at 29 years 9 months, and the furthest travelled British-ringed Curlew, at 2,541 kilometres to Russia.
The Treatment WorksSince 1994 good numbers of birds have been caught and ringed within the treatment works, around the filter beds where insects provide a rich source of food, particularly in cold and wet weather in Spring and Summer. Just over two thousand Swift, four thousand House Martins and two thousand Swallows have been ringed here, along with smaller number of Yellow Wagtails, Pied Wagtails and Meadow Pipits. Another British-ringing record is ‘held’ by Marston with the two longest-lived Swifts at 17 years, 11 months and 16 years 11 months respectively. Around the edges of the works, landscaping and planting provides scrub and tree habitat for other species including several warbler species. Over the last 6 years twenty five Chiff Chaff have been caught during the winter months of October to March when these birds would normally migrate to Africa showing that there is plenty of food available to sustain them over this period.
Reed-bedThe creation of a permanent reed-bed in 1996 increased the numbers of reed dwelling species such as Reed and Sedge Warblers. Over the last five years increased effort has meant that the number of each of these species has risen giving an average of about a hundred a year of each over this period.
Ringed Bird Movements to and from Marston STW
General
The subsequent reporting rate for a ringed bird is surprisingly low and is less than one per hundred ringed. Of the 16,441 birds ringed at Marston STW, only 83 birds (around 0.5%) have subsequently been reported by others, including 23 birds overseas. (But excludes birds both ringed and subsequently ‘retrapped’ at Marston STW). In addition another 72 birds have been caught at Marston STW having been ringed elsewhere, including 8 from overseas.
A map showing the longer movement details follows in Appendix 2 (page 8) and the full list of every recorded bird movement follows in Appendix 3. (Pages 9 – 19)
Wildfowl and Waders
Generally speaking, the larger the bird is in size, the greater chance of having a ringed individual recovered. The ringing of ducks and waders has therefore produced more recoveries than passerine species. The map of recoveries clearly shows that Teal and Curlew migrate generally in a north-northeast to/from south-southwest direction, whereas Snipe originate from a more direct easterly direction and continue through Marston into southwest England and Ireland and into France and the Iberian peninsular.
The Pectoral Sandpiper, an American vagrant, seen in Hertfordshire just twelve days after being ringed at Marston is the only recovery of a British-ringed Pectoral Sandpiper.
The Spotted Redshank, shot in France just eleven days after being ringed at Marston, is the fifth to France out of ten foreign recoveries from less than 400 ringed in Britain.
Swifts and passerines
Eleven Swifts have been subsequently recovered out of nearly two thousand ringed, and a further nine have been caught having been ringed elsewhere. Two Swifts ringed in the same area of the West Midlands in the early 1980’s and caught at Marston are the oldest known swifts from British ringing, at 17years 11months and 16years 11months. Two other Swifts had been ringed as chicks at Helpringham, and four other were ringed as breeding adults at Ancaster. The recoveries from Swifts ringed at Marston show that the vast majority originate from the surrounding area, especially Grantham. This shows just how important the site is for locally breeding Swifts particularly in cold weather.
The fact that only one Swallow had been subsequently recovered out of over six hundred ringed up to 2005, illustrates the poor recovery rate of small birds. However in the last 3 years we have caught considerably more birds ringing 1451 of which 24 have been recovered or controlled. This has increased the recovery rate to 1.6%, which is a huge improvement.
House Martins on the other hand have produced a lot of both controls and recoveries, but this was due to the fact that another ringer was carrying out a study locally of breeding birds. Again, the fact that so many locally breeding House Martins regularly feed around the filter beds at Marston illustrates how important this site is.
The handful of other passerine recoveries include the first British recovery of a Yellow Wagtail from Belgium and a Sedge warbler to France and one from Norway.
The full details of every bird either controlled at Marston, or subsequently recovered follow on pages 9 to 19.
Appendix 2Recoveries and controls of birds caught at Marston Sewage Treatment Works
RINGED BIRD MOVEMENTS TO AND FROM MARSTON Details of Ringed Birds (Recoveries)
Ringing details are given on the first line and recovery data on the second or subsequent lines. The first line entry is normally, ring number followed by an age code, date of ringing and place of ringing. On the next line there is a code for the manner of recovery (if known) followed by date and place of recovery.
The distance that the bird has moved (if any) is given in kilometres and the direction of movement . The last figure is the duration between the ringing date and subsequent recapture.
The age code is given according to the 'Euring' code and do not represent the age in years, but are as follows:
odd number = bird of exact known age even number = exact age not known
1 = pullus, nestling or chick
2 = full grown, but exact age unknown
3 = hatched during current year
4 = at least one year old
5 = hatched during last year
6 = at least two years old
7 = hatched two years ago
8 = at least three years old
M = Male
F = Female
J = still in juvenile plumage
The manner of recovery is as follows:
r = retrapped (caught again at same site by ringer)
c = caught or retrapped by others
vv = ring number read in field
x = found dead or dying
xc = killed by cat
xr = killed on road
xw = killed against window
xo = killed on overhead wires
xp = killed by bird of prey
xl = long dead
xf = freshly dead
+ = shot or killed by man
? = manner of recovery unknown
A full list of ringed bird movements to and from Marston STW follow. For each species, any ‘controls’ (birds ringed elsewhere and subsequently found at Marston) are given first; followed by any ‘recoveries (birds ringed at Marston and subsequently found elsewhere).
Appendix 4Fact Sheet - Bird Ringing in Britain and Ireland
The British and Irish Ringing Scheme is organised by the British Trust for Ornithology (BTO). Around 800,000 birds are ringed in Britain and Ireland each year by just over 2,000 trained ringers, most of who are volunteers. On average, fewer than one of every fifty birds ringed is subsequently reported to the BTO, so every report of a ringed bird is of value.
The RingersThe skills necessary to become a ringer can only be learnt by practice under the close supervision of experienced ringers. Essential skills include the safe and efficient trapping and handling of birds, identification, ageing, sexing, measuring, record keeping and reporting to the British Ringing Scheme, For this reason, ringers undertake a period of several years, during which they are only allowed to ring birds under supervision. An independent ringer, whose own ability has been judged to a high standard, assesses their progress through the permit system. In this way the BTO Ringing Scheme maintains very high standards of bird welfare and scientific data. A BTO ringing permit is also a legal requirement and is, in many ways similar to a driving licence but has to be renewed annually.
How are birds caught for ringing.Birds are caught for ringing in a variety of ways. Nationally almost twenty percent are ringed as chicks in the nest; this is valuable because their precise age and origin are then known. The method most frequently used to catch fully-grown birds is the mist net. This is a fine net erected between two vertical poles and is designed to catch birds in flight. This method is very effective, but birds can only be removed safely from mist-nets by experienced ringers, who have received special training.
Why do we ring birds?Much has been discovered about birds by watching and counting them, but such methods rarely allow birds to be identified as individuals. This is essential if we are to learn about how long they live and when and where they move: questions that are vital for bird conservation. Placing a lightweight uniquely numbered metal ring around a bird's leg provides a reliable and harmless method of identifying birds as individuals. Each ring also bears an address, so that anyone finding a ringed bird can help by reporting its whereabouts and fate. Some ringing projects also use colour rings to allow individuals to be identified in the field.
After one hundred years of bird ringing in Britain and Ireland, we are still continuing to discover new facts about migration routes and wintering areas. However the main focus of the Ringing Scheme today is the monitoring of bird populations. Ringing allows us to study how many young birds leave the nest and survive to become adults as well as how many adults survive the stresses of breeding, migrating and severe weather. Changes in survival rates and other aspects of birds' biology help us to understand the causes of population declines. Such information is vitally important for conservation for a wide range of species, particularly those of current conservation concern.
Ringing has allowed us to show that the declines in the number of some species such as Sedge Warblers breeding in Britain and Ireland was linked to lower levels of rainfall in the African wintering quarters. We have also found that the recent dramatic decline in the numbers of Song Thrushes has been a reduction in the survival rate of young birds. This information will help us to identify the environmental factors responsible for the decline.
Does ringing affect the birds?The simple answer is no. It is essential that birds are not affected unduly by the fitting or wearing of a ring. If they were, ringing would not tell us how normal birds behaved. Many studies have shown that birds ringed during the breeding season quickly return to incubating eggs or feeding chicks, once they are released. Also long distance migrants continue to travel many thousands of miles between breeding and wintering grounds. Birds will not be affected as long as ringing is carried out by skilled ringers with the utmost consideration for the bird's welfare. It is not surprising that ringing has little effect on birds because, relative to the birds weight a ring is similar to a wristwatch on a human.
Please report any ringed bird that you find Please report details of a ringed bird to: The Ringing Unit
BTO
The Nunnery,
Thetford
Norfolk
IP24 2PU
Or alternatively on the Internet: http://www.bto.org/
The ring Write down the ring number and, if the bird is dead, please enclose the ring taped to your letter. (The ring can be returned to you if you so wish to keep it). If it is not a BTO ring (address starting BTO or British Museum) please give the address as well.
Where Give the location that the bird was found including the name of the nearest town or village and a grid reference if possible.
When Give the date that the bird was found.
Circumstances Say if the bird was alive or dead. If dead, please give the cause of death if known, e.g. was it hit by a car, brought in by a cat, or found oiled on a beach? Also note if the bird was freshly dead or decomposed etc. If the bird is alive, please say what happened to it.
The bird Write down the type or species of the bird, if you know.
Your details Do not forget to give your name and address so that you can be sent the information about where and when the bird had been ringed. Details will normally be sent within a month, but there may be delays at busy times of the year or for rings with foreign addresses.
Appendix 5 - Some of the birds caught at Marston.
The odd pair of Teal occasionally breed at Marston, but most occur in autumn on passage or in winter. It is a small duck and has a green speculum or wing-bar. The bird featured is a female; males have a striking chestnut head with a broad green stripe behind the eye. Teal are easier to catch than the larger ducks, which tend to land and take off almost vertically. The recovery rate for ducks is relatively high, as one would expect, as many are shot. Four Teal, from 45 ringed at Marston, have been subsequently recovered. The overseas recoveries in Finland, Denmark and France illustrate a more north-south migration route almost identical to Curlew, rather than the more east – west migration route of Snipe.
This Short-eared Owl is one of the most unexpected birds to be caught and ringed at Marston. It was caught whilst it was hunting at dusk, just after nets had been set on the fields in order to catch waders at night. Although Short-eared Owls breed in very small numbers in Lincolnshire, this individual was almost certainly a wintering - individual from Scandinavia. Short-eared Owls are best known for being more diurnal than other owl species, but they are most active at dusk and dawn. On this particular day this Short-eared Owl and a Long-eared Owl were seen hunting over the fields at the same time.
The Snipe is the most numerous wader that occurs at Marston. A few pairs breed and probably stay all year, but in autumn varying numbers pass through on migration, heading south-westwards from eastern Europe. In good Snipe years, if conditions are good at Marston, and surrounding countryside is dry, there can be several hundred Snipe on the fields. Although generally difficult to catch, because they tend to land and take off quite steeply, the fact that they are so numerous makes this species to be by far the most numerous wader caught at Marston.. To date over 600 have been ringed here, subsequently resulting in recoveries in Spain, France, Cornwall and Ireland
The Pectoral Sandpiper is the rarest species of bird to be caught at Marston. It is a rare visitor to Europe from arctic America, but is the most frequent American wader to be found in Britain, usually in Autumn. One of the distinctive identification features is its streaked upper breast, which stops abruptly above its white belly. This particular bird was seen at Tring just twelve days later. Although the ring number was partially read by binoculars in the field, photographs and stages of moult confirmed the individual sufficiently enough to enable it to be accepted as the first ‘recovery’ of a British – ringed Pectoral Sandpiper
The Green Sandpiper breeds in the far north of Europe and winters around the Mediterranean and further south in Africa, though small numbers overwinter in Britain. It is an unusual wader in that it does not nest on the ground like most wader species, but nests in old songbirds’ nests particularly those of thrushes in trees.
It is not very numerous, but is a regular autumn visitor to Marston, though a few occasionally are seen in winter. Two birds ringed at Marston were retrapped at Marston during a subsequent autumn. Both birds were moulting at Marston and had clearly recognised Marston as a suitable ‘stopping off’ site, in order to moult, and illustrates the importance of such a site.
The Wood Sandpiper is very similar to the closely related Green Sandpiper, and has the same breeding and wintering ranges, though it nests on the ground like most wader species. It is slightly smaller than the Green Sandpiper and is more brown above and has lighter greener legs. It is a fairly scarce autumn migrant and is nowhere as numerous as the Green Sandpiper. Less than four hundred have been ringed in Britain and we have caught five at Marston
