During the next few weeks nearly half the world's population of birds will undertake their spring migration.
Millions of birds will surge through Africa heading for their breeding grounds in Europe while our winter migrants such as geese, ducks and waders will fly towards the Arctic Circle and beyond.
It is therefore a period of great change at Montrose Basin.
So, where are the breeding grounds of our winter migrants? Where is their ultimate destination?
Throughout April and early May all of the UK's wintering population of pink-footed geese (around 250,000) will migrated from the Scottish mainland to Iceland. They will fly non-stop and the 800-mile journey will take 14 to 18 hours depending on weather conditions.
Some birds will then move on to Greenland Pintail, wigeon and teal will breed in Iceland, Scandinavia or Russia Shoveler will travel to Eastern Europe and scaup to Iceland or the Baltic States.
Waders too make long journeys Knot will travel as far as Arctic Canada, turnstone to Greenland and bar-tailed godwit to Scandinavia and Northern Europe.
Although some redshank, golden plover and black-tailed godwit breed in the UK, many more will choose the wild and isolated areas of Iceland as their summer residence.
Our summer visitors to the Basin will start their journey in Africa and are trans-Saharan migrants March arrivals include wheatear, sand martin and osprey.
Wheatear winter south of the Sahara in a broad belt from east to west coast Sand martin travel from Northwest Africa and osprey spend their winter fishing in coastal and inland waters in Senegal and the Gambia.
The first recorded sighting of osprey at the Basin this year was on March 28th.
Willow warbler, chiffchaff and sedge warbler will arrive from West African states such as the Ivory Coast or Ghana. The swallow has a longer haul, migrating all the way from South Africa Sandwich and common tern will have wintered along the west coast of Africa.
Migration can be full of hazards and many birds will perish along the way. For those that arrive at their destination the race is on to establish territory, find a mate and set in motion the breeding cycle which will secure the birth of the next generation.