Basin Notes - January 2000

"Water, water, everywhere, nor any drop to drink"

This is hardly true even on the "dry" side of Scotland, as that most discussed of weather features, rain, makes Scotland the repository of 90% of Britain's lochs and reservoirs. It is, however, more apt when applied to the Basin, which at high tide contains about 3,000 million gallons of water. Unfortunately for us the meeting of fresh water from the South Esk with sea-water from the North Sea produces a cocktail of intermediate salinity (fresh water contains less than 0.5% salt and sea water averages 35% salt) which is not drinkable.

The 2,000 acres of mud, sand and gravel holds about 100,000 million corophium shrimp and 200,000 million hydrobia snail. Add to that, myriad lugworms, ragworms, cockles and mussels and 10,000 to 30,000 birds and it is clear that it is just the right environment for some organisms.

The Basin is, like all estuaries, a challenging place even for those animals and plants that proliferate in and under the water. Each day the Basin fills and empties twice. To survive you must be able to stand being wet half the time and dry the other half with varying degrees of light and warmth in between times and resist the changes exerted by salinity ranging from fresh water to seawater. Certainly, the human population of Montrose would not survive for long in such extreme conditions.

For the soft-bodied animals living in the mud like lugworms and ragworms the best strategy is to hide in deep burrows to avoid the extremes of the conditions and also change their body chemistry on the fly when exposed. Molluscs like cockles and mussels just shut the "doors" of their shells and hide behind their calcium armour until better conditions return.

These survivors in the mud provide a vital link in the food chain by consuming all the dead animal and plant material and making themselves juicy morsels for the birds and fish to eat. Without this army of cleaners there would be no birds to gladden our hearts with their flight and song. The great pity is that it is very difficult to see the worms, shrimp and molluscs as they react to the ebb and flow of the tide. You can, however, see these unsung heroes of the Basin magnified with the microscopes in the Wildlife Centre.

The bird life on the basin is locked into the changing tides as much as the mud life. The birds follow the advancing and receding water catching any unsuspecting worms, shrimps, crabs and molluscs that have not retreated to their shelter in response to the changing conditions.

Birdwatching on the Basin has to follow the same pattern and from the Wildlife Centre the best view is two hours before and two hours after high tide as the hungry beaks probe for tasty morsels at the very edge of the water. From the Wigeon hide at the west end of the Basin the best viewing is at high tide as the birds find a roost side to sit and wait for the receding tide to reveal their prey once more.

To be prepared for these spectacles of nature, copies of the tide tables for 2000 can be obtained from the Wildlife Centre or phone 676336 for advice on the state of the tide. Time your visit carefully to get the best sight of bird - and worm - activity.