Why do we ring birds?

[Peter]

Why do we ring birds?

Much has been discovered about birds by watching and counting them, but such methods rarely allow birds to be identified as individuals. This is essential if we are to learn about how long they live and when and where they move, questions that are vital for bird conservation. Placing a lightweight, uniquely numbered, metal ring around a bird’s leg provides a reliable and harmless method of identifying birds as individuals. Each ring also has an address so that anyone finding a ringed bird can help by reporting where and when it was found and what happened to it. Some ringing projects also use colour rings to allow individual birds to be identified without being caught.

Although we have been ringing birds (Britain and Ireland) for nearly 100 years, we are still discovering new facts about migration routes and wintering areas. However, the main focus of the Ringing Schemes today is monitoring bird populations. Ringing allows us to study how many young birds leave the nest and survive to become adults, as well as how many adults survive the stresses of breeding, migration and severe weather. Changes in survival rates and other aspects of birds’ biology help us to understand the causes of population declines. Such information is so important for conservation. The BTO, for example, runs two special projects to collect it. The Constant Effort Sites (CES) scheme provides information on population size, breeding success and survival of bird species living in scrub and wetland habitats. Ringers work at over 130 CES scheme sites each year. The Retrapping Adults for Survival (RAS) project gathers survival data for a wide range of species, particularly those of current conservation concern.

A notable example of the importance of ringing was to show that declines in the number of Sedge Warblers breeding in Britain and Ireland was linked to lower levels of rainfall in their African wintering quarters. The BTO have also found that the recent dramatic decline in the numbers of Song Thrushes has been caused by a reduction in the survival rate of young birds. This information will help us to identify the environmental factors responsible for the decline.

Does ringing affect the birds?
 
The simple answer is no. Ringing is carried out by skilled ringers with the utmost consideration for the birds’ welfare. It is not surprising that ringing has little effect on birds because relative to the bird’s weight, wearing a ring is similar to a person carrying a mobile phone. It is essential that birds are not affected unduly by the fitting and wearing of a ring; if they were, ringing would not tell us how normal birds behave. Many studies have shown that birds ringed during the breeding season quickly return to incubating eggs, or feeding chicks, once they are released, and long distance migrants continue to travel thousands of miles between breeding and wintering grounds.
 
How are birds caught for ringing?

Birds are caught for ringing in a variety of ways. About twenty percent are ringed as chicks in the nest; this is valuable because their precise age and origin are then known. The method most frequently used to catch fully-grown birds is the mist net. This is a fine net erected between poles, and is designed to catch birds in flight. This method is very effective but birds can only be removed safely from mist nets by experienced ringers who have received special training.

Learning to ring

The skills necessary to become a ringer can only be learnt by practice under the close supervision of experienced ringers; effectively an apprenticeship. Essential skills include the safe and efficient catching and handling of birds, identification, ageing, measuring and record keeping. For this reason, ringers undertake a period of training, generally of two or more years, during which they are only allowed to ring birds under supervision. Their progress is assessed by an independent ringer, whose own ability has been judged to be of a high standard. In Spain the ‘trainee’ has also to pass a written exam before acquiring the status of ‘Experto’ and progressing to being able to ring birds unsupervised. In this way the Ringing Scheme maintains very high standards of bird welfare and scientific data. A Spanish ringing permit is also a legal requirement for anyone ringing birds. It has to be renewed annually.

[john]

I think the really interesting question is how much longer are we going to bother to ring birds?   OK ringing can provide data about longevity, population dynamics etc., but it's an extraordinarily inefficient way to find out about bird movements.  Most of the birds caught are never seen again and,  for most part, all you just get a simple 'snapshot' of where & when a bird happened to have been caught and where it was retrapped. 

Rest easy, Peter, this isn't going to be a diatribe against ringing, but my point is that technology has already reached a stage where relatively large birds can be tracked using tiny transmitters and it can't be too long before this technology will be suitable for much smaller species.  Cost per bird will obviously be higher, but the amount of information gleaned from even a relatively small number would quickly outweigh that attained by years of conventional ringing,

John

[Peter]

Ah yes, but then again your methodology would have several shortfalls like juvenile/adult survival rates etc., etc.

I have emailed you a rather large file 'The contribution of bird ringing to conservation'. I rest my case.

Peter

[john]

OK ringing can provide data about longevity, population dynamics etc., but it's an extraordinarily inefficient way to find out about bird movements. 

Peter, I happily concede your point ... which I included within 'etc' .... the thrust of my argument concerned migration,

Thanks for the file!

John

[Collalba]

I pinched the intro to this thread for copying onto another forum! Hope nobody minded

At least here nobody is going out of their way to get insulting and the thread seems very calm and uncontroversial. You do get some very distorted/bigoted views put forward on the  pros and cons of ringing, so its good to have a straightforward thread.

John, in the absence of any economically better way then guess the methods used here for monitoring migration has to be the only one to make sense?

Collalba