Annual Royal Swan Upping takes place on River ThamesPublished19 July 2016Image source, PAImage caption, A count of the Queen's swans has taken place on the River Thames. Each year a team get in boats and get out on the river to check how many of the birds there are.Image source, Getty ImagesImage caption, On certain parts of the Thames, swans called mute swans are owned by the Queen. They are counted by the Royal Swan Marker and his team. This tradition has been going on for the last 800 years.Image source, Getty ImagesImage caption, It's not always an easy job to catch and tag the swans. This bird doesn't seem too keen.Image source, Getty ImagesImage caption, Once they've managed to get hold of the birds they check they are healthy and add them to the count which is called a census.Image source, Dan KitwoodImage caption, The number of new baby swans, called cygnets, is recorded to see how well the population is doing.Image source, Dan KitwoodImage caption, This cute cygnet has been weighed and tagged to check it is healthy.Image source, PAImage caption, This girl got a chance to meet a young swan.Image source, PAImage caption, The birds are measured, weighed and tagged when they are caught. Don't worry it doesn't hurt them and then they are set free again.More on this storyAnnual swan count under way on River ThamesPublished21 July 2015Chester Zoo's annual animal countPublished5 January 2016Watch: London Zoo begins its animal countPublished5 January 2015