During the entirety of January and the majority February ringing has been off the cards so on some days we took our exercise by the Thames, recording rings of swans and hoping to see the occasional Black-headed Gull carrying darvics.
Over the two months we have collected a lot of data, but also provided some much needed food for the birds. At Windsor there is an artificially high population of Swans, due to constant feeding by visitors and tourists. They are quite an attraction, but we have noticed that birds have little natural food around that stretch of the Thames, many not even recognising green leaves such as spinach or lettuce as food. They tend not to move far from the river to graze on the Brocas and many birds do not even leave the source of an easy meal to breed during the breeding season.
So the prospect of birds starving during the winter months was a real worry with tourism not currently possible at Windsor. We would feed the birds a couple of times a week and as time went on it became more and more frequent that we would see families feeding bread or grain. Some Windsor residents were clubbing together to buy 15kg bags of sea duck food pellets to see the Swans through the worst of the weather.
During a period of high water, coming over the river bank, some swans finally took to feeding themselves and a number were seen out on the grass which they took to consuming for themselves. It also gave an opportunity to read more metal rings than usual and produced some birds that either had not been reported for a few years and in some cases since they were first ringed.
We did come across a couple of interesting data queries.
Mute Swan with EGI (Edward Grey Institute Oxford University) Y3T (colour ring) with metal ring ZY6622 upon being entered into the BTO national database came up as having been reported dead. Contacting Prof Chris Perrins at EGI who made checks, the bird's history was traced, having been originally ringed as W28320 when a juvenile back in summer 2011. The bird lost its metal ring and was re-ringed with ZY6622 in summer 2014 during the annual Swan Upping. Enquires with the BTO regarding the report of the bird being found dead revealed in fact only the metal ring had been found by a diver metal detecting on the bottom of the River Thames. It was obvious the bird had lost its ring, which happens occasionally if they strike anything, the banks in some parts of the Thames are concrete or metal, so if they haul themselves out they can catch the ring on the bank side, or sometimes due to striking an object in the river they open up and eventually fall off. The bird was clearly alive, and the report of the bird being found dead was deleted.
X3Y, another EGI bird, whilst checking the above birds history we noticed that X3Y was recorded as being on W42526, a male, but appeared to be in fact a female in real life. Checking the Profs 2018 & 2019 Swan Upping records, they showed W42526 having darvic Y3A and X3Y was shown with metal ring ZZ2694, being a breeding pair in 2018 & 2019 at Clewer. Again checking the BTO data base showed that in error W42526 had been shown with X3Y and ZZ2694 as Y3A. Whilst we were all pretty sure that the Swan Upping entries were correct, before changing the national BTO database we needed to be sure, and eventually we managed check, as shown below X3Y clearly fitted with ZZ2694. The BTO database was changed to reflect the right darvic code v metal ring, and the sightings, and the process of getting all sightings changed from W42526 to ZZ2694 followed, though some other observations still have not been changed over.
We also found out that W42526 had also lost it metal ring and in Swan Upping 2019 had been re-ringed with ZY6681, still with colour ring Y3A, but despite being a local breeding male, was last seen in August 2019 and has been absent for the last 18 months, possibly dead.
The oldest Swans recorded was almost 17 years old, W07039 having been ringed originally in July 2004 at Henley during Swan Upping. After this the oldest birds were ringed in 2010.
During the period when the rain had pushed up the Thames water level above the river banks in some areas birds came out to feed on the grass, and a number of metal rings read related to birds that had not been seen since their first ringing, such as W42610 not seen since being ringed in November 2016.
Very few Canada Geese are ringed in the area but one bird ringed as part of a DEFRA study back in July 2004, 5233569 was present, though it had long lost its orange colour ring YLD, now being nearly 17 years old.
Windsor is not always a good location for picking up colour ringed Gulls, but one 6HF has been a regular since February 2017 having been ringed in March 2015 in Kobenhavn, Denmark as an adult.
2BDC - ringed Rutland Water June 2019 as a juvenile in breeding colony.
2J59 - ringed Pitsea rubbish tip March 2017 as an adult.
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Most Mute Swans on the Thames only carry metal rings, but EGI also add white colour rings to Swans during Swan Upping only, but historically far more were given white rings, but these days only a few will be found with them. To report these contact Prof Chris Perrins at Edward Grey Institute, Oxford University. His interest mainly relates to breed birds or if found dead.
Other Swans may carry an orange colour ring, part of Mike Reed's South & East Anglia Swan project, some of which were ringed by Mike and us locally, and occasional ones appear on the river after rehabilitation at local Swan rescue centres, being released back onto the Thames after being picked up in other areas locally. To report these email mike.reed2017(at)outlook.com
