FOR the last few weeks our skies have been filled with formations of foreign birds.

Their approach is announced by a low rhythmical whooping sound, then wing tip to wing tip in giant v-shaped formations gaggles of canada geese race overhead. As their name suggests, they are natives of North America and are common in Canada.

The climate, which the birds occupy in America, is much harsher than in Britain Our climate is heavily influenced by the warm oceanic current known as the Gulf Stream. This current flows up from the Gulf of Mexico bringing with it warm waters that have a warming influence.

Canada geese in their native North America have to migrate south for winter some even flying thousands of miles south to the Gulf of Mexico. During this migration the geese often form great v-shaped formations that are a regular and distinctive feature of an American autumn or fall as they would call it.

In England the birds do not need to fly south. Despite this, some birds feel the primitive instinctual urge to do at least some flying and that is why we see the small formations of birds flying fairly regularly at this time of year.

Canada geese were introduced into Britain in the early 1800's as ornamental birds to enliven the lakes and pools of stately homes and mansions.

Since then these birds have colonised Britain and have a particular attraction to ornamental ponds and gardens.

The appeal of these areas is that they prefer to feed on short-cropped vegetation and don't like to be surrounded by trees or use pools with large amounts of emergent vegetation.

There is also the additional appeal that on some pools the geese can supplement their diet by scrounging food from passers by.

Canada geese's numbers have dramatically risen since introduction.

They can overgraze the land surrounding the pools, creating muddy areas which are unsightly and covered in their droppings. Where pools are supporting artificially high numbers of geese the droppings that go into the pools enrich the water with nutrients.

This leads to blooms of algae which feed on these nutrients and in doing so deplete the pools waters oxygen levels, killing off all other life.

So whilst you can admire the birds please refrain from feeding them to allow native pool wildlife a chance to flourish.