First published October 2018

Throughout this winter, right through to the 31st March next year, the British Trust for Ornithology (BTO) is undertaking a nationwide survey of the tawny owl, UK’s most common owl. This survey has two aspects to it, firstly, volunteers are assigned areas, a kilometre square tetrad and they have been asked to visit their site on 2 occasions and these took place in September or October.

The second arm of the survey is open to anyone and can be undertaken anywhere, you can take part of from the comfort of your own bed by just opening your window and listening! All you need to do is listen for 20 minutes each week between now and the end of March. It doesn’t matter if you miss a week, all records are welcome as are those that don’t record any owls at all; the absence of owls in an area is as important information as hearing one calling. If you are interested in taking part in the survey, you can download the information from the BTO website ( and the tawny owl survey information is on the opening page.

As I said originally, the tawny owl is our most common owl, but it isn’t seen that often because of its very nocturnal behaviour, we are much more familiar with its call, the archetypal ‘too-whit, too-whoo’ sound the floats through the night skies. Although it is our most numerous owl species, it is on the Amber List of species for conservation concern, this means that its population has declined between 25-50% over the last 40 years. One of the main reasons for the survey is to build on previous survey information from 12 years ago and to see if the increasing urbanisation and the subsequent light and noise pollution is having an impact on tawny owl breeding success. In the more rural areas, loss of habitat is another potential reason for their decline.

Henfield seems to be doing quite well for tawny owls, this is mainly from anecdotal evidence and also a continuing monitoring project undertaken by David Plummer through Henfield Birdwatch. Over the last couple of breeding seasons, a number of tawny owl sites were found and chicks were heard at these sites. At Woods Mill, there was a very vocal family of three chicks and on one lucky occasion I was able to see one of the adults feeding a hungry youngster. Also, a very prominent family held a territory along the Downslink where on a dusk walk I encountered a curious youngster staring down at me from a branch across the track.

Hearing the call of a tawny owl of an autumn night is one of the great natural sounds of the UK. It can for some people sound quite eerie and in days gone by, many myths and stories have been associated with it, many of them relating to death or dark deeds. For the owl though, it is merely the best way of communicating to each other through the hours of darkness. If you hear the ‘too-whoo’ sound then it is the male proclaiming a territory to other males and also trying to attract a female into it, whereas the ‘too-whit’ sound is usually a responding female, so you are in fact hearing two owls.

While still fairly common, it is sad to think that this wonderful, iconic bird is declining, so any help in finding out where these birds are will be of great help in finding ways to make sure that they are still around us in the future.

Mike Russell