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Ringed Birds and What They Tell Us

Ringed black guillemot

Sometimes when we are out doing bird surveys or working on a site we come across ringed birds. It might have just a metal ring, or one combined with a series of coloured rings or flags. Some larger birds, such as geese and raptors, may have neck collars or wing tags. But what sort of information can we find out from bird ringing? In this post we’ll look at its history and continued importance for studying and conserving birds.

The Beginning of Bird Ringing

People have marked birds in some way for centuries. Early marking was for identification purposes. Falconers, for example, used plates to mark their birds at least as far back as the 1500s. One of the first people to recognise that marking birds could be used scientifically was the bird artist John James Audubon in early 1800s America. He tied threads to the legs of some young eastern phoebes and could tell from these that they returned to the same site the following year to breed. Gathering this information about site faithfulness would not have been possible without the threads.

Ringed birds brent goose
This brent goose has a combination of metal and colour rings

The first organised scheme to ring (or ‘band’ as it is known in the USA) birds began in Germany in 1903 at the Rossitten Bird Observatory. Other countries followed suit over the next decade or so including three schemes set up in the UK in 1909. The American Bird Banding Association was founded in the same year.

Most of these systematic approaches used uniquely numbered lightweight metal rings for each bird. The aims were to answer two main questions: where do our summer visitors spend the winter and where do our winter visitors breed? This was because, at that time, little was known about the movements of our migratory species.

Early Successes and Limitations

It didn’t take long before ringing in the UK was providing vital information about migration. In 1912, for instance, the first recovery was made of a ringed swallow in South Africa. This showed without a doubt that birds breeding in northern Europe travelled to the Southern Hemisphere for the winter. Very little had been understood about birds’ long-distance migrations before this. Some believed into the nineteenth century that swallows hibernated at the bottom of ponds, for example.

People used to believe that swallows hibernated rather than migrated

Although by the 1930s the UK had a unified nationwide scheme organised by the BTO, there were some limitations to the project. The main issue was that using metal rings relied on physically recovering birds, whether alive or dead. In the early days, recoveries were almost always from dead birds, found and reported by the public. Of course, there was no guarantee anyone would find a ringed bird when it died. This was especially true when it came to smaller, less visible species, or those in remote places. This meant the percentage of recoveries was understandably small.

It wasn’t until the middle of the twentieth century that Heligoland traps and mist nests were first used to capture live birds. These enabled trained specialists to catch birds for initial ringing or to check for rings.

By this stage, ringing’s aims had broadened as well. In addition to finding out about migration, rings were now also used to find out about productivity and survival. That means how many young are produced and how many of these young and their parents survive. This is vital information for focussing conservation efforts.

Colour Ringing

Despite the use of mists nests and Heligoland traps, the fact remained that using metal rings meant people could only read the identifying codes with a bird in the hand. Mist netting at the same site each year during the breeding season certainly improved the chances of recapturing a ringed bird. But birds are not always site faithful and so valuable data was still lost.

To solve this problem, in the last few decades, ringers increasingly use plastic colour rings on suitable birds in conjunction with metal ones. (Smaller woodland birds tend not to be colour ringed as it is difficult to see the rings amongst dense foliage.)

Black-tailed godwit
This black-tailed godwit has a combination of colour rings to identify it

Being able to see plastic rings in the field through binoculars, scopes or on photos mean there is no need for recapture. Sometimes marks will be a series of different coloured rings in a unique combination. More recently, there has been an increase in the use of ‘Darvic’ rings. These are made of Darvic PVC, which is extremely hard wearing. A sequence of letters and numbers is engraved on them which can be read at a distance. This makes them especially useful for larger birds like gulls and raptors. BTO metal rings are still always used as well. This is in case a project accidentally duplicates the colour combination or code of an overseas scheme.

Anyone who sees a ringed bird can report the details on the Euring website. Euring coordinates bird ringing efforts across Europe, recognising that birds don’t recognise borders and that sharing information is crucial to research and conservation.

Ringed birds herring gull
This Weymouth ringed herring gull is clearly showing both its metal and Darvic rings

What Can We Learn from Ringed Birds?

Although ringing’s aims have broadened, understanding bird movements is still vitally important. If we know where migratory birds spend different parts of the year, we can find out what pressures they face at any of those locations and concentrate conservation efforts accordingly.

This doesn’t just apply to classic long-distance migrants such as terns or warblers either. Ringing has shown us that some species behave differently in different locations. For example, UK robins stay fairly close to their breeding territories. Some continental birds, though, are migrants who travel to us in cold winters.

Ringing also illustrates some interesting migratory quirks. Conservationist Matt J Bruce saw a colour-ringed female whinchat in Shetland this May. Whinchats don’t breed in Shetland, but he was able to find out that she had been ringed in Cumbria last year. Despite overshooting on her spring migration from Africa by 350 miles, Matt heard from the ringing project in Cumbria that within three weeks she had recalibrated and was back at her breeding site. Without her colour rings, it would have been easy to assume an overshooting whinchat in Shetland would miss out on a breeding opportunity, at least for this year.

Ringed curlew
This curlew ringed by the Highland Ringing Group is providing valuable data on a species in sharp decline

Crucially, though, the main focus of ringing is now on studying bird population changes in all species, not just migratory ones. This means finding out how many young are produced, how many survive to fledging, how many survive their first year and how many adults survive year to year. Ringing tells us which species are doing well and which are declining. This enables us to identify where help is most needed.

Where young are ringed in the nest and we know their birth year, it can tell us about birds’ ages. Without ringing, we wouldn’t know that Manx shearwaters can live to the age of at least 50, for example. Understanding all aspects of a species’ ecology, including lifespan, helps us to protect them better.

Safety First

Of course, it is extremely important not to put any birds at risk and undermine the conservation benefits of ringing them. Under the Wildlife and Countryside Act 1981 as amended, all bird ringers in the UK must be licenced and carry out hundreds of hours of training. This training ensures they know how to trap and handle birds whilst causing them minimal stress and without harming them. The bird’s welfare is always paramount. Fortunately, studies have shown that despite the small amount of stress handling them causes, birds very quickly relax once released and there are no long-lasting effects.

Although none of us at Purple Plover are ringers, Andrew was extremely privileged to be invited to observe the Shetland Raptor Study Group ring some sparrowhawk chicks recently. Sparrowhawk numbers have been increasing in Shetland over the last five years. Ringing is helping the group to understand this population rise. The chicks were all given Darvic rings, and the hope is that this will build up a picture of whether these birds stay on the islands or move elsewhere.

Sparrowhawk ringing
This sparrowhawk chick is being ringed by a highly trained licenced ringer

Projects like this across the country are carried out by dedicated and extremely knowledgeable individuals. These are often volunteers. Despite the development of satellite and GPS tagging, ringing is still an important conservation tool. With its help, we are better placed to help birds as more and more species face serious population declines.