Swan monitoring in Norfolk - 17th November 2024

 Every year we get a large (for us) team together to monitor Mute Swans. This is part of the continuing project lead by Mike Reed to assess swan movements and longevity. We make capture of birds in their hatch year a priority as they are of a definite known age and they also provide an insight into productivity for that year.

The team for today was MR, CL, DKL, PWL, DMD, CVG, PAM, EPL, CJH and EGB.

Swans were captured by hand, ringed and fitted with individually identifiable darvic leg markers at Whitlingham Country Park, Hoveton bridge, Wroxham Broad and Potter Heigham. The individually coded rings allow further observations without the need to capture the birds. We also recorded a further 20 birds that had been ringed and marked under this project previously.

For many of the team this was a new experience, completely different to mist netting and ringing passerines that makes up so much of the training to ring. Our group did exceptionally well, working together in a real team effort to achieve a good day of monitoring.

Mallard catching proved more difficult than the swans

It was particularly pleasing to capture a small family group at Potter Heigham. This group of cob, pen and a single cygnet were the only swans at this location. The pen was captured first and fishing line with a hook embedded in her foot was successfully removed before she was fitted with a metal ring, darvic coded 4GTW and released.

Looking at the number of cygnets ringed to adult birds, this catch seems to be down compared to our last two winters. In early 2022 we did two days at the same sites and got 23 birds hatched in 2021 and 54 adults. Adult numbers were high due to an absence of monitoring during 2020 and 2021 as a result of the Covid19 pandemic. The catch in 2023 was in early December and at that time of the 32 birds marked it was an even split 16/16. This session, we only got 7 cygnets and 18 adults. Mute Swans are long lived birds and a breeding season may be abandoned by some pairs if conditions are too problematic. It's not straight forward to interpret how this might reflect on this years breeding season as it was very wet at the start of the year and some first attempts may have been unsuccessful.  This is not just a case of possibility of flooding. We know of a case where the nest was built at the edge of the water and by the time the flooding subsided there was too much dry ground between the nest and the water. This attempt failed and the birds did not try again at that site.

This autumn has been unseasonably warm. We only saw one obvious family party and they were not with other swans. There may still be family parties where the young remain with the parents out on the broads and in general, there may still be birds that have not yet needed to move to areas such as Hoveton Bridge, where there is a designated feeding platform and the public regularly feed birds. In the winter this tends to inflate the numbers of swans present at this site. It was noted that some cygnets, either independent of parents or where parents are 'encouraging' them to leave were kept away from food or did not join the feeding flock, remaining distant from a few, more mature, aggressive individual birds. These factors play into the numbers present and captured in addition to other possible factors such as the potential effect of weather conditions and Avian Influenza over the past few years.

Many thanks to the Broads authority and trustees of Whitlingham Country Park for permission to monitor at these sites. All ringing activities undertaken under the appropriate British Trust for Ornithology licence and relevant endorsements.

Please report any sightings to Mike Reed - mike.reed2017@outlook.com

Totals: 27 new, 1 recapture, 20 re-sighted

Mute Swan - 25 (1) [20]
Mallard - 2

6M Mute Swan

January and February 2021 - Windsor

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.

ZZ 2694 - X3Y

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.

W07039

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.

W46210

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. 

5233569

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.

But, the 5th January turned out to be a bit of a bumper day with six new colour ringed Gulls present:

2BDC  - ringed Rutland Water June 2019 as a juvenile in breeding colony.
2J59    - ringed Pitsea rubbish tip March 2017 as an adult.

2V00   - ringed Kensington Gardens March 2020 as an adult.

2TTR  - ringed Pitsea rubbish tip March 2017 as an adult, on the same day as 2J59.

EE7E  - ringed Griend, Netherlands July 2015 as a juvenile in breeding colony.

EE9W - ringed Griend, Netherlands June 2016 as second year bird in breeding colony.

2TTR

2J59

2V00

EE7E

EE9W

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.

EGI white darvic Y3T

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

Orange darvic 4DYH

River Thames, Windsor - 6 and 12 January 2015

We've had another very windy spell and haven't been able to get out to ring much yet this year so  took a walk along the Thames at Windsor to look for colour rings on Mute Swans.

Over the two dates we found several black on orange colour ringed birds. These birds have been ringed at Ruislip Lido and the surrounding area by Mike Reed.

This female was colour ringed at Ruislip Lido on 24/10/2013. 

We also picked up 041 (black on orange) on our second visit and wait to see whether  this is a different series used on Mike's study.

There were also several birds with black on white darvics. We already have some details for these, but others have yet to come through. So far, all were local birds. There was a time when many more of the swans at Windsor had white darvics but now they are becoming less common.

L3C

When birds stand out on the bank it's sometimes possible to read the metal BTO ring

 Chris tries for a clear view while birds preen on the bank

I photographed some, successfully, too.

We were really quite excited to see white on blue TO32 as we've never seen a dark blue one here before. 

T032

It seemed to match with a series issued by the Latvian scheme on dark blue. But ever keen to ensure reliable data is recorded, Chris made further enquiries just to make sure the O was not a 0. As it turned out, it was 0 and not O, and it was ringed under a project on juvenile dispersal at Winchester, so rather less well travelled than we first hoped. It was ringed on 3rd October in 2012.

Finally, we also witnessed the rescue of a Mute swan from between two barges. As ringers, we  are used to working under close scrutiny. I can't help thinking that I might have tried to increase the gap between barges rather than yank the bird out by its neck.