Thursday, 28 July 2011

Mist netting - a necessary evil?

Birdguides has just posted an article about a study into the safety of mist netting birds. This is a subject that often gets non-ringers hot under the collar and I wish I had an extra pan-species lifer for every time that I've heard somebody say that it is a cruel practice. It is something that I know a little bit about.

Between 1976 - 1983 I held a ringing permit, becoming an A permit holder and a trainer by 1979. I have spent a great deal of time handling many thousands of birds, from tiny Goldcrests right through to the veritable avian giants such as geese and swans. Most of these were trapped by mist net (not the geese and swans however!). A mist net, generally, only becomes dangerous to a bird when the person extracting it from the net is inexpert in the process. It takes a person with a 'feel' for the fine mesh to confidently untangle the bird from it. There are situations when weather can play a part in safety - a windy day can tangle birds beyond comfort, rain will chill them as will cold - but any ringer worth his salt will not operate in such conditions.

There are horror stories. Mist nets set over water to trap waders that have collapsed, drowning those birds caught. Trapped birds being predated by cats, rats or even Water Rails. These are rare events. The odd bird does get injured. The odd bird does die (Bullfinches and Greenfinches have a reputation for 'croaking it' in small - and I mean small - numbers).

Such losses are totally regretable, but are very rare. The data that ringing has given us has helped identify migration routes, wintering and breeding ranges, longevity figures, the means to assess the health of birds through fat counts and 'stress' bars on feathers - all in all a tool to help protect millions of birds across their whole range. I feel that the odd loss can therefore be justified.

It is also worth remembering that the light metal ring that is placed on a birds tarsus is specifically designed to allow a bird to carry on its normal life unhindered. Otherwise all data gathered would be meaningless. The use of plastic rings has been used to successfully allow larger birds, such as geese and gulls, to be identified in the field without the need for repeated capture to gather data. The longevity of these birds provides proof that they carry on living an unhindered life.

Read the article if you are a sceptic and it may provide you with some comfort as to the effects that mist netting (and ringing) has on birds.

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