I AM a keen local birdwatcher and would invite Mr Isaacson to join me on a walk around the Roswell Pits area so that I can help share the Marsh Harriers, Bitterns and other special birds in the area. Can I assure your readers that the species mentioned

I AM a keen local birdwatcher and would invite Mr Isaacson to join me on a walk around the Roswell Pits area so that I can help share the Marsh Harriers, Bitterns and other special birds in the area.

Can I assure your readers that the species mentioned are present, and although Roswell Pits is not the easiest place to see the birds, the site IS used and incorporates part of their breeding or feeding territories.

There are three pairs of Marsh Harriers present and although Bitterns have "boomed" their territorial call at Roswell Pits in the past they are currently adjacent to the site. However, in the winter the pits holds up to three Bitterns and I believe a co-ordinated roost count of all suitable sites would reveal upwards of five birds using the watercourses. Otters and their spraints (evidence of this very elusive species presence) are monitored across the county by trained volunteers in co-ordinated schemes.

It is ridiculous to make the assumption that all otter sightings relate to mink and discredits the work of the experienced and dedicated surveyors who put in so much time and effort. The amateur and professional ecologists who collect data on this site and many others across the county are passionate, scientific experts in their "craft" and records are validated and recorded year on year at the Cambridgeshire and ­Peterborough Biological Records Centre (www.cpbrc.org.uk).

This allows population trends to be monitored and valid data provided for exactly the kind of debate that is growing about the future of Ely's riverside green spaces.

I would encourage Mr Isaacson and others to refrain from publicly spreading uninformed misinformation and instead to seek out those who can share and inform them about the incredible birds, plants, mammals and insects around the city then they may appreciate the fragility of the whole riverside corridor.

I, for one, will spend time with anyone wanting to learn more about the biodiversity of the area. In the words of Joni Mitchell: Don't it always seem to go that you don't know what you've got till it's gone, they've paved paradise and put up a parking lot.

DUNCAN POYSER

Bohemond Street

Ely