Monday, 11 July 2022

Mid-way through our Constant Effort Sites scheme - June 2022

Across our country, bird ringers are working together by generating data for the BTO's Constant Effort Sites scheme. This programme monitors the breeding success, decade-on-decade, of 24 species.

Of these, two are on the 'Red list' of the Birds of Conservation Concern (BOCC): Song Thrush and Willow Tit; and four are Amber-listed: Dunnock, Willow Warbler, Bullfinch and Reed Bunting. 

The other species are Wren, Robin, Blackbird, Cetti's Warbler, Sedge Warbler, Reed Warbler, Whitethroat, Lesser Whitethroat, Garden Warbler, Blackcap, Chiffchaff, Long-tailed Tit, Blue Tit, Great Tit, Treecreeper, Chaffinch, Greenfinch and Goldfinch.

Twelve surveys take place each year to make up a complete data survey. This June, we completed the fifth and sixth surveys of the twelve.

The fifth session bucked the year’s catching trend and was significantly up on 2021 which helped this year pull back on last year’s numbers. One still left feeling we’re missing a third of the catch.

We did see some older birds this month: two Garden Warblers ringed by us in 2015. Garden Warblers migrate to Africa each winter and in these cases, that's seven-round trips since being ringed - mindblowing when you see how small these birds are (they weigh less than 20g).

The site's flora was in full bloom...

Bird vetch
Bird vetch
Centaurea nigra
Centaurea nigra
2 Pyramidal orchids
Myosotis nemorosa Wood Forget-me-not

Wednesday, 1 June 2022

Summer is here for our breeding birds - May 2022

Birds don't wait until our summer to breed and some of our species, like pigeons and cormorants, can start laying as early as January!

Our Blue Tits aren't as early as those species but do get a head start on returning migrants by laying from the end of April and fledging young as early as May. That gives us some busy sessions checking boxes and (digitally) filling out nest record cards to contribute to the national scheme.

We have a few boxes at a nature reserve, just outside Maidenhead. These boxes have had a good year, with all being occupied.

Blue Tit box-checking for the annual national survey

One of our boxes had the unwelcome attention of a Grey squirrel so we added protection to the front of the box to keep the chicks safe.

A second front was added to this box to stop squirrels chewing their way through to the nest

Sessions at Befont produced an interesting Reed Warbler which we'd ringed as an adult in 2014 making this bird at least eight years old and eight round-trips between Bedfont and Africa!

We ran three sessions at Wraysbury to continue our Constant Effort Site programme. Numbers were down compared with last year and we will have to await the national report to see how the site has faired compared with the broader picture.

Bedfont had two other interesting recoveries: a Cetti's Warbler ringed in Titchfield Haven National Nature Reserve last October. And a Bedfont colour-ringed, in 2019, Common Tern chick was seen down in  Dorset this May.

Common Tern & Cetti’s Warbler Bedfont recoveries mapped

Wednesday, 4 May 2022

Migrants return - April 2022

This month the group returned to Wraysbury to prepare the site for the CES and catch the migrants as they returned to the country.

Top species were Blackcap (41 individuals), Chiffchaff (14) and Dunnock (11). By the last session (which was CES #1) we recorded the season’s first Garden Warbler (6) and 3 further Whitethroat (we’d captured our first on 15th). Regulars noted the absence of Willow Warbler this year - we’d recorded five last year and this April we didn’t even hear any song.

I took four of our trainees around the woodland boxes at Woolley Firs on 23rd. Last year I had reduced the number of boxes to be intune with the thinning of trees carried out by BBOWT. All remaining boxes were occupied and all but two had begun clutches.

I mentioned to the trainees that we had a couple of years of Great Tits nesting in a Tawny Owl box at Woolley. A great example of a bird’s natural instinct to build a nest even when the choice of site is far from ideal. In both years the clutch successfully fledged. We removed the box after seeing this two years running and put up a smaller box, just for the tits.

A Great Tit nest at the bottom of an owl box

Friday, 1 April 2022

Hardwork ready for spring - March 2022

Most of this month’s activity at Bedfont has been spent reclaiming the net rides from the Covid-induced jungle. The increase in Chiffchaffs has been noticeable and last weekend Blackcaps were singing, both being caught at some point during the sessions. The Blackcaps were carrying a good amount of fat which was good to see.

A few hours here and there and a good couple of mornings and the site is looking much better. There’s still plenty to do but I think it should pay off in the future.

At Woolley Firs, March can be a tough month for ringing as the winter flocks disperse and the summer migrants are yet to arrive. The stormy weather didn’t help and we didn’t get to Woolley until 15th; a Tuesday as we finally got the message that calm weekends weren’t to be taken for granted.

Rewards included a Danish-ringed Redwing and some rather good-looking Brambling.

Young male Brambling feeding-up at Woolley Firs

We opened the site at Wraysbury and found the site in good shape. The catch included Chiffchaffs and Blackcaps and one of the Blackbirds could be seen with-egg - nature is getting on with the year!

Trainees reading the literature between rounds

Tuesday, 1 March 2022

Reasons to be grateful - February 2022

 This month last year a combination of lockdown and poor weather prevented the group from ringing any birds (only forty sightings of twenty-six colour-ring birds were entered).

So this month we can be thankful that although the storm season got serious - storms’ Dudley, Eunice and Franklin crossed the UK in only seven days - we were lucky to lose only one weekend of netting to them.

On the 12th we ran a public ringing demonstration. Over twenty turned up, including some who had traveled from Bristol to see their first bird ringing session.

Despite the cold, the feeders were fairly quiet and we only caught 21 birds. This was enough to provide a backdrop while we explained why ringing is important to conservation and science, and provided an opportunity to see birds up close.

Tricia of BBOWT said that they had turned away twenty additional people and that suggests we should be running more demos!

Tuesday, 1 February 2022

Good weather finally! January 2021

 The month’s weather got off to a good start enabling the group to run six sessions.

The month's total of 204 captures was a site record; well ahead of the previous best of 161 in 2015. While there is much context to take into account I can say that it’s unusual to see tit flocks in large numbers at the site after Christmas.

Feather condition: we noted a couple of Great Tits with poor quality body feathers; possibly a result of an infestation (enough for us to sanitise after handling these individuals).


Ageing House Sparrow

Svensson’s Identification Guide to European Passerines notes that House Sparrows cannot be aged after the completion of the young post-juvenile moult and the adult post-breeding moult. Laurent Demongin’s Identification Guide to Birds in the Hand notes plumage differences that can be used to age males. So we gave it a go…

Monday, 3 January 2022

End of year ringing - December 2021

 The year finished with unsettled weather but the group did get out to Minet and Woolley Firs while a garden site added some House Sparrows to the totals and the River Thames, a Polish Black-headed Gull sighting.

Change is afoot at Woolley Firs: arable farming has ceased and those fields left to go to seed. This has seen the beginnings of a revival for the site with over 200 finches, mainly Chaffinch, but also ~50 Linnet.

Despite those finch numbers, a poor forecast had us start at the woodland feeders on 11th. In practice, it was probably calm enough to have tried the fields! Still, the feeders produced 155 birds including two Nuthatches and a Firecrest. We packed up as rain threatened.

The 155 birds, spread across twelve species, gave good experience to two new trainees (35 birds processed between them) and a new trainee on her first taster session.

The poor breeding season across the region was evident in the day's catch: the age ratios are quite depressed when compared with birds caught in previous Decembers.




Age ratio Juvenile : Adult

Blue Tit December 2021



2.6 : 1

WF Wood historic December ratio

3.4 : 1

Great Tit December 2021



1.6 : 1

WF Wood historic December ratio

2.1 : 1

Polish-ringed Black-headed Gull at The Thames, Windsor