Crop Field Ringing 19th April - Breeding is under way!

We had our first session of the breeding season down in the crop field area.  It was a very cold start but developed into a particularly beautiful day weather wise (though a little too bright and sunny for ideal ringing conditions), as you can see from a picture of the busy team for the day (minus myself). 

I had cleared some new rides in the Colyford Common reed bed for us to use and we set nets in our usual areas otherwise.  The reed beds are still a little quiet as yet, but the new rides did catch us a few birds including a reed warbler, one of our target species, and a swallow.  Overall it was quite a productive day for the four of us, with a good mixture of birds including some we don't catch particularly frequently which is nice, especially when they may be locally breeding.  

Our total for today, or 41 birds encountered, is given in the table.

	New Birds	Retraps	Total
Blackbird	1		1
Blue Tit	1		1
Cetti's Warbler	2	2	4
Chaffinch	2		2
Chiffchaff	4		4
Dunnock	4		4
Great Tit	3	3	6
Greenfinch	2		2
House Sparrow	1		1
Linnet	2		2
Long Tailed Tit	1	1	2
Reed Bunting		1	1
Reed Warbler		1	1
Robin	3	1	4
Sedge Warbler	1		1
Stonechat		2	2
Swallow	1		1
Wren	2		2
Total	30	11	41

As always at this time of year we are looking for signs that the birds are breeding locally.  We check the birds for signs of cloacal protuberance and/or brood patches.  We can use cloacal protuberance to relatively easily sex some of the birds as male, and we can use the extent of the brood patch to sex some birds as female.  We also look for these indicators in birds we can sex by plumage so we have some idea whether they are breeding in the area or are passing through, perhaps still migrating north.

The picture below shows a greenfinch we have sexed as female based on her plumage with a very obvious and clearly defined brood patch.

Cetti's warblers cannot be sexed on plumage differences, but one we caught we thought might show signs of having cloacal protuberance, but we were not certain, so released it unsexed and watched it fly into the reeds 5 yards away and then sing loudly to us!

The unusual birds for us included the two linnets, which we catch one or two of per year.  The bird on the right, though with very little pink colouration, is a male, while the bird on the left is female.  They were caught side by side in the same net.  The female was starting to develop a brood patch, though there was no sign of cloacal protuberance on the male.

Similarly swallow is a bird we might expect one or two a year, though I always think we should perhaps get more as they skim over the reeds. 

The sex of a swallow can be determined by the relative lengths of the tail feathers. A male has longer 'streamers' which is effectively the length of the outer most tail feather. We measure the difference in length between the outer feather and the feather next to it and/or the shortest tail feather. This bird has relatively short streamers and was sexed as female.

Stonechat feel as if they are increasing in numbers, and we have a pair or two breeding.  The stonechats we caught today were both male, but there was also a female collecting nesting material just by where we were ringing.

House sparrows are very nice to catch, and this area is one where we might expect to catch at least one most sessions.  They travel down from the local houses (in the back of the linnet photograph) to feed in the grassy area in the old crop field and are readily caught moving between bramble bushes or in the gateway between two hedges. 

Another interesting record was a reed bunting which we caught for a second time, having caught it initially in the reed bed by the Discovery Hut during one of our evening roost catches.  This suggests this bird does not move much!  It was showing signs of breeding and we also saw a female collecting nesting material.

So overall a very interesting session which gave us some good indications as to what is happening in that area of the reserve.  We will be visiting again shortly so will keep you updated!

Mist netting 10/4/26....the migrants are here!

Things have picked up! A group of us had a session in the vicinity of the Discovery Hut which proved to be a different kettle of fish to the last one.....the migrants have arrived and gave us an interesting morning. We set seven nets and caught 36 birds of 13 species. Our very first bird was very exciting....a Reed Warbler that had been ringed by the Group on 17/6/2017, caught twice in 2018, and hadn't been caught again until today. The life expectancy of a Reed Warbler is about 2 years, and as this bird was an adult when it was ringed, it must now be at least 10 years old.  It's amazing to think of how many miles it must have travelled going backwards & forwards to sub-Saharan Africa each year, a total distance of about 54,000 to 60,000 miles. In an odd coincidence, it was in 2017 that we last caught a Reed Warbler that was of a similar age...we caught a bird on 24/5/2017 that had been ringed as an adult on 16/7/2009, making it at least 9 years old. The oldest recorded Reed Warbler was 12 years, 11 months & 21 days old, so just a couple more trips & our bird will be a record breaker. 

A very well travelled 10+ year old Reed Warbler

Reed Warbler wing 

We caught three Willow Warblers, our first of the year. They also migrate to sub-Saharan Africa for the Winter. Adult Willow Warblers undergo two complete moults each year, one after breeding before leaving the UK, and one whilst in their wintering quarters in Africa. The juveniles undergo a partial post-juvenile moult, and then also complete a full moult in Africa before returning. Therefore, there is no way to age a returning Willow Warbler.

Willow Warbler

Willow Warbler wing

Willow Warblers are often more yellow and have paler legs than a Chiffchaff. However, there's a lot of individual variation, and some can be hard to tell apart. Before ringing, it is therefore necessary to correctly identify which species you have. This is done by looking carefully at the Primary feathers. On a Willow Warbler, the outer vane is emarginated (ie narrows) only to the 5th Primary feather, whereas on a Chiffchaff the 6th feather is also emarginated. As the wing shape is also slightly different, the length of the 2nd Primary on a Willow Warbler is roughly the same length as the 5th or 6th Primary, whereas on a Chiffchaff it would be about the same as the 7th or 8th. 

Willow Warbler wing

We did catch four Chiffchaffs, which did show the typically duller plumage when compared to the Willow Warbler. 

Chiffchaff

We also caught the Group's 21st Woodpigeon, an adult female with a large brood patch,  indicating that she's actively breeding. 

Woodpigeon

Woodpigeon uniform adult wing

One Reed Bunting was caught, which had been ringed as a young male on 2/11/25. 

Male Reed Bunting (age code 5)

The Team

	Ringed	Retrapped
Reed Warbler	1	2
Cetti’s Warbler	1	1
Willow Warbler	3
Blackcap	7
Sedge Warbler	5
Wren	1	1
Reed Bunting		1
Chaffinch	1
Blackbird	2
Chiffchaff	3	1
Blue Tit	1	2
Dunnock		2
Wood Pigeon	1
	26	10

There were plenty of Sand Martins whizzing about over the reeds & visiting the nesting wall. So far at least 19 nest cavities are being visited & contain nesting material, and two of the nests already contain an egg. Sadly there are at least two less Sand Martins than arrived back from Africa. One was taken in the air by a raptor, and one was taken from the front of the wall by a Moorhen, which then drowned the Sand Martin before swimming off with it. The wall will be monitored weekly & the youngsters ringed when old enough. 

We have also received very late notification of a Reed Warbler which was ringed by the Group on 17/6/25 as a juvenile bird, and which was subsequently caught on 16/8/25 in Caminha, Viana do Castelo, Portugal, 60 days & 1077km later.

A quiet morning...28/3/26

Four of us set six nets around the reed bed & feeders. It was pretty cold at the start, and as it warmed up the wind increased, so not ideal conditions. It proved to be a very quiet session, with only 12 birds caught, of which 9 were re-traps. Having low numbers is actually good for training as you can take the time to explain the various ageing features, and having re-traps is useful as you can check the accuracy of your conclusions against earlier records. So, although quiet, it was a very pleasant training session!

Our three Blackbirds were an interesting set. 

The first was an adult male (age code 6), ringed as an adult in August last year, which had a lovely uniform black plumage, apart from one white feather in the left wing. 

Adult male Blackbird

Uniform adult wing....with one white feather!

Next came an adult female Blackbird (age code 6), first ringed as an adult in October 2024, which had a nice uniform brown plumage. This bird had a large well defined brood patch (code BP2), so she's probably started or completed a clutch of eggs.

Adult female Blackbird

Adult female wing

Our third Blackbird was an un-ringed male, which had a very obvious moult limit, with the brown juvenile flight feathers & Primary Coverts contrasting with the new black feathers replaced as part of its post-juvenile moult.

Male Blackbird, hatched last year  (age code 5)

Wing of male Blackbird hatched last year (age code 5)

One of the other re-traps was a Blue Tit which had been ringed as a young bird in August 2022. The life expectancy of a Blue Tit is about 3 years, so it's already doing quite well.

	Ringed	Re-trapped
Chiffchaff	1	1
Blackbird	1	2
Wren		1
Dunnock		2
Sing Thrush		1
Blue Tit		2
Chaffinch	1
	3	9