General information on the colour-rings in use for Dark-bellied Brent Geese (Euring-code 1681).

All birds have been ringed with one colour-ring (of about 1 inch high) on each leg. In some cases only one colour-ring has been used, but then a small metal ring has been put on the other leg. These colour-rings bear contrasting inscriptions in either black or white, depending on the background-colour used. These inscriptions are either letters or digits repeated three times around the ring for easy identification. Also rings with one, two or three horizontal bars have been used. In some cases we have used double digit inscriptions, also repeated three times around the ring.

The colour used, are: light-blue or light-green (lime), white, yellow, orange, red, dark-blue or dark-green. To maximize contrast with the background colour either white or black inscriptions have been used. Note that in dark- blue rings the white of the inscriptions is often so conspicuous that some observers take these rings for white rings, because the ring itself is hardly visible against the black leg. For ring colour we always refer to the background-colour of the ring itself. A limited number of plain colour-rings without inscription has been used in the 1970-s.

Using powerful telescopes (40 – 60 x magnification) allows the inscriptions to be identified at 200 – 300 metres distance. Some telescopes distort the colours when used at full magnification. We therefore recommend to check for the colour of the ring at lower magnification. In the remark field you can also add information as to the colour of the inscription itself (either white or black) as this may help us to identify the bird you have seen. E.g orange rings invariably bear black inscriptions, whereas red rings always bear white inscriptions.

At present the following colours are in use:

yellow with black inscriptions or without inscription (notated as Y) white with black inscriptions or without inscription (notated as W) pale green (lime) with black inscriptions (notated as L) dark green without inscription (notated as G) pale blue with black inscription (notated as B) pale blue with white inscription (notated as B) dark blue without inscription (notated as B) dark blue (almost black) with white inscriptions (notated as B) orange with black inscriptions (notated as O) red without inscription or with white inscriptions (notated as R) much smaller metal rings (notated as *) black with white inscription (notated as N)
	Brent Goose OYR9 (left orange Y; right red 9) accompanied by young bird (Tim Crawshaw)

Notation of ring combinations:

It is important to note which ring is on the left and which is on the right leg.

In the code identifying a bird we use a four-symbol-code. The first one indicates the colour of the left ring, the second one the inscription engraved on the left ring, the third symbol indicates the colour of the right ring and finally the fourth indicates the inscription on that right ring. Some examples:

• ‘W8YH’ means a white ring with 888 on it on the left leg, and a yellow one with HHH on it, on the right leg;
• ‘R Y5’ is a bird carrying a red ring without inscription (note the space on the second position!) on the left leg and a yellow ring with 555 on it on the right;
• ‘OJ*’ means an orange ring with JJJ on it on the left leg and a small metal ring on the right.
• Some birds have been marked with a colour-ring bearing a double inscription, e.g. ‘F2’ of ‘AY’: on one ring and a metal ring on the other leg. These are, in case yellow rings have been used, indicated by ‘YF 2’ (note the space on the third position!) and ‘YA Y’ respectively;
• YZY= : means a bird with a yellow ring with three horizontal bars (triple bar) on the left leg, and a yellow ring with two horizontal bars (double bar) on its right leg
• WAY- : left a white ring with a black A, and right a yellow ring with one black horizontal bar (single bar)
We have always used one ring one each leg, but a few birds have lost one ring, so please check very carefully for an inconspicuous metal ring on the other leg in case you see a bird with just one colour-ring.

Black neckbands used on Brent

Since 1985 Brent Geese staging in spring on Langenwerder Insel near Rostock in the former German Democratic Republic have also been marked with black neck-collars bearing a white three- digit code, or a letter with two digits next to it.

Notation HA39 : Black neckband(H) with inscription A39 (Note: The standard way in which we code black neckbands as used on Greater White-fronted Geese will in the future also be used for Brent)

Only fully identified birds are of interest to us.