Into the reeds: reedbed passerines and a Gambian surprise

This week we gathered a team to clear net rides in the reed bed of one of our most productive sites, situated in the Yare Valley. Over the weekend we had our first sessions on site since clearing the net rides, and was the first sessions on site this year. The site has a long history of bird ringing activity, and enables us to monitor populations of your typical reed bed passerines, and a few stars of the show. With plenty of eager helpers in the group, we're hoping for a bumper year of ringing on site this season.

We ran two ringing sessions this weekend, one on late Saturday afternoon leading into an evening Swallow roost catch and a second session the following morning. We caught 232 birds over the two sessions across 9 species. 75 these birds were Swallows caught into roost and all were this year’s juvenile birds. This can probably be attributed to most adults currently tending to their second broods, rather than roosting in the reed bed. Surprisingly the roost catch didn’t produce any wagtails, despite hearing Yellow Wagtails in the reed bed earlier in the evening. This may be an indication that the larger roosting numbers are yet to build this year.

The most exciting surprise of the weekend came in the shape of a Reed Warbler sporting a shiny blue British Museum ring. A quick check of DemOn told us it was ringed on the 9th January this year, our interests peaked and a phone call later, we realised we were looking at a Gambian control! Of course every adult reed warbler we handle has made a trip from Sub-Saharan Africa, but one sporting a Gambian ring is something special. The bird was ringed at Kartong Bird Observatory as part of a BTO supported project that targets ringing of Western Palearctic migrants. When you consider the far lower density of ringers in Africa compared to what we are accustomed to in Europe, the huge numbers of individuals that undertake these journeys, and the massive spatial scale, it's a pretty exciting control!

Figure 1. Roughly 4,600km from The Gambia to Norwich, it's a long flight for a ~12g bird

Whilst they are an expected catch on most sessions on site, Bearded Tits are always a welcome catch and were a particular treat for those in the group that haven’t experienced the species before. With 22 caught, numbers on site at first impression seem healthy and with 13 of the 22 individuals being juveniles it seems like another successful breeding season.  Other highlights included singles of Garden Warbler, Whitethroat, and Greenfinch. The latter a species both trainers in the group, who have ringed this site for many years, couldn’t recall being caught here before. Being a juvenile male, it is perhaps a dispersing individual.

Diurnal passerine numbers in the reed bed seemed in good stead in general, and hopes are high for many more productive sessions at the site over the coming months.

Table 1. Capture over two sessions 3-4^th August 2019. Number of juveniles in brackets.

Species	New	Retraps	Total
Bearded tit	22 (13)	0	22
Garden Warbler	1 (1)	0	1
Greenfinch	1 (1)	0	1
Reed Bunting	9 (5)	0	9
Reed Warbler	97 (65)	2 (0)	99
Sedge Warbler	21 (21)	1 (1)	22
Swallow	76 (76)	0	76
Whitethroat	1 (1)	0	1
Wren	1 (0)	0	1
Total	229	3	232

A cracking adult male Bearded Tit sporting its characteristic full ‘moustache’. An expected catch on site, but no less special for it.

This juvenile female Bearded Tit was just one of 13 juveniles caught across the two sessions. Like most of the juveniles she was undergoing a complete moult (hence why it she’s a little scruffy), one of the relatively few British passerines that do so.

The most abundant reed bed passerine on site, the Reed Warbler. The two sessions saw us catch 99 individuals.

The star of the show, a Gambian ringed Reed Warbler. The blue anodised metal rings were originally used in the UK for a House Martin project that aimed to increase recovery rates, but remaining rings after the project ended were given to the Gambian ringing scheme.

A juvenile Sedge Warbler, showing the ‘necklace’ of black spots seen in juveniles.

Group update, and a bumper Spring/Summer of garden ringing

It’s been a reasonably quiet spring/summer for UEARG so there isn’t much to update on. Nest boxes on campus were checked earlier in the season and produced plenty of broods of Blue and Great Tits, a reasonable year productivity wise it seemed. Other than that, members of the group have joined other local ringers or groups assisting with their CES (constant effort site) activities, and other bits and pieces such as swifts, raptor pulli, and spotted flycatcher pulli. We’ve also had group members going further afield with their ringing, visiting Bird Observatories such as Fair Isle and Calf of Man, and even as far as Iceland. Things should hopefully start to pick up now though as the summer progresses and Autumn comes ever closer. This morning six of us gathered for a big net-ride clearing and preparation session at one of our best sites in the Yare Valley, and should allow us to get back on site to monitor how the birds are doing.

For this blog I thought I’d briefly touch upon a surprising addition to group ringing totals this year, mine and Kirsty’s garden. If you’re a ringer or have spoken to a ringer about how many different individual birds are coming to your feeder, I’m sure you know it’s way more individuals than you would think. Even so, we’ve been pleasantly surprised by just how many are using our relatively modest sized garden (10x20m ish). We are lucky enough to have a garden that backs onto a small woodland, so I’ll preface the numbers with that, but we’ve had 358 different individuals across 18 species. Those totals cover just 4 months of ringing in our garden since we moved in, and with new individuals caught each session it’s set to rise further. Typical catches are dominated by a handful of species (e.g. Blue Tit, Great Tit, Dunnock, Robin), and we have been inundated with juveniles. Perhaps another sign that the tits have had a productive breeding season.  The biggest surprise for us however, has been the number of different Jays that visit the garden. Today we caught number 12! Other highlights have included confirmed breeding of species such as Bullfinch, Chiffchaff, and Greenfinch in the area. The woodland is relatively young growth and has has had extensive management in the past, so natural nest cavities are in short supply. This may help explain the lack of some typical woodland species such as nuthatches or treecreepers.

Table 1. Garden ringing totals 31/3/2019-31/7/2019. Brackets show number of juveniles, which have dominated our catch.

Row Labels	New	Retrap	Total
Blackbird	19(8)	8(1)	27
Blackcap	2	0	2
Blue Tit	104(85)	23(21)	127
Bullfinch	3(1)	0	3
Chaffinch	23(19)	1(1)	24
Chiffchaff	6(4)	1(0)	7
Collared Dove	2(1)	0	2
Dunnock	25(18)	11(4)	36
Goldfinch	8(2)	0	8
Great Tit	107(67)	85(71)	192
Greenfinch	8(2)	0	8
Jay	12(3)	3	15
Long-tailed Tit	1	0	1
Magpie	2(1)	0	2
Robin	23(18)	27(7)	50
Starling	1	0	1
Woodpigeon	9(3)	5(3)	14
Wren	4(3)	0	4
Grand Total	358	164	522

The juvenile Jays have only just started visiting the garden in the last week. Their underparts are still downy and and the bright blue wing covets show less black barring.

Great tits seem to very readily enter the potter traps here, whilst we seem to catch far fewer blue tits in them.

A fresh juvenile Bullfinch, probably left the nest the day we caught it. 

Comparatively more black barring in the wing covets of this adult Jay, and lacks the downy underparts of the juvenile (above).

A staple of garden ringing, a fresh juvenile Blue Tit.

One of our potter trap setups, placed on a bird table I built. The tits seldom enter the traps if they are placed on the ground.

The garden in question (and Sparrow, the dog).