….. worth two in the bush

Reed Warbler

The chance to join a bird ringing session was an opportunity not to be missed, so when friend and fellow WSRS member Bill Parker mentioned he would be ringing later that week, in a conversation during our recent sound recording trip to Somerset, I was quick to ask if I could join him to watch and find out more. On the appointed morning I left early and headed across country to meet up with Bill and his ringing partner Garry Marsh. I found them tucked away in the shade, a couple of hours of ringing already behind them.

A stunning male Bullfinch

The ringing of birds began in 1909 when two schemes were instigated. One under the auspices of British Birds magazine and its editor, Harry Forbes Witherby and the other led by Arthur Landsborough Thomson of Aberdeen University which was brought to a close by the advent of World War I. A third was also set up by Country Life magazine, though their rings were not uniquely numbered. With the establishment of the British Trust for Ornithology (BTO) in the 1930s, responsibility for the British Birds scheme transferred to them. Since these early beginnings bird ringing has sought to answer the ornithological conundrums of the day, most notably in understanding migration. Today that work continues with collected bird data contributing to our understanding of bird longevity, mortality and life-cycle.

Garry and Bill had arrived early, setting up their mist nets in the pre-dawn half-light. Four nets were erected, each rising to a height of 9-10 feet, held sturdy by bamboo poles and guy ropes. Fine black netting hung loosely in four or five parallel lines, hardly visible if you approach head on. The locations had been chosen carefully; one by the reeds, 90 degrees to the water’s edge, two more in the mixed scrub close to the hedge and another in the more heavily wooded spinney close to the ringing station. Patrols were made every 20 minutes to check the nets and bring back any birds for ringing.
Recovered birds are placed in cloth bags and then individually inspected. A ring is attached carefully around the bird’s leg and its number is noted. Against this are written the particulars of the individual, firstly identifying species by general inspection. Sex is determined by plumage characteristics in most species, though there are exceptions, including  dunnock, willow warbler, chiffchaff, song thrush. Here, identification is assisted by gently blowing onto the breast and cloacal area, where the cloacal protuberance (CP) or brood patch (BP) is used to indicate sex. Additionally, in spring the BP and CP are checked on all birds as it indicates stage of breeding / sexual maturity. The CP is indicative of a male, their maturity and breeding status in the breeding season. When checking the breast, the brood patch is inspected. The colour of the bare skin and the general appearance indicates whether the female is or has incubated eggs. These features are noted with a grading number and then measurements are taken of the length of wing and overall weight of the bird, before it is released from the hand to continue its morning’s activities.

After each burst of ringing activity there was a chance for a slurp of coffee and a quick chat, before the process began again. During one of these we discussed the immense amount of species knowledge that is required. I was relieved to discover that not all of it is held in their heads! Reference works support them, with Lars Svensson’s Identification Guide to European Passerines having been the go-to work for over 50 years in it’s various editions. Joining the field in recent times is a new book by Laurent Demongin called Identification Guide to Birds in the Hand. Both are absolutely fascinating, packed as they are with identifying information, data and measurements to assist in identifying, ageing and sexing any bird in Europe. It has to be said though, that during my time with them, neither Garry nor Bill had course to refer to these wonderful treasure troves – my bet is bird ringers could give taxi drivers a run for their money in the memory stakes.

Blowing gently on the abdomen to identify gender

The weigh-in. A bird the size of a sparrow typically weighs around 28 grams or 1 oz

Four-spotted chaser in the mist net before being safely removed and released unharmed

Blackcap female – with a brown crown, compared to the male’s black.

As the morning drew on, catch numbers began to dwindle so after a final check of the nets the session came to a close. A marvellous morning and one I’m extremely grateful to Bill and Garry for letting me experience. The data they capture, along with the countless other dedicated ringers across the country have made an immense contribution to our scientific understanding of the natural world and birds in particular. New technology, including satellite tagging is now able to bring us new insights through virtually live data streaming, allowing us to track individual birds with tremendous detail. But bird ringing will retain it’s place as a critical tool in bird study and continue to contribute to our understanding. As a final note, here are a few species longevity records that could only have been demonstrated through ringing.

SpeciesYear of record/location foundAge
Mute Swan2009/Dorset29 years 1 month 11 days
Wigeon1996/Russia34 years 7 months
Fulmar1992/Orkney40 years 10 months 16 days
Red Kite2012/Wales23 years 10 months 18 days
Moorhen1963/Oxfordshire11 years 3 months 20 days
Puffin2012/Scotland36years 11 months 22 days
Turtle Dove1974/France11 years 2 months 15 days
Robin1977/Blackpool8 years 4 months 30 days
Blue tit1997/Bedfordshire10 years 3 months 10 days

Further information and references
BTO Bird ringing history
Lars Svensson’s Identification Guide to European Passerines
Laurent Demongin – Identification Guide to Birds in the Hand
Bill Parker on Twitter
Garry Marsh on Twitter
Bill Parker on Soundcloud

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