Thames Swan census expects rise in numbers for 2015

The Queen's Swan Marker, David Barber, said air gun shootings were often to blame for swan deaths

The number of swans on the River Thames recorded in the annual census is expected to have risen, despite the deaths of two breeding pairs.

The Queen's Swan Marker, David Barber, said there had been an increase in air gun shootings, particularly in Windsor, Berkshire, during the winter.

"We've lost at least two of the breeding pairs this year because of the shootings," he said.

The Swan Upping ceremony commenced at 09:00 BST in Sunbury, Surrey.

The five-day survey also passes through Oxfordshire and Buckinghamshire.

Last year, the census recorded 2,014 swans, including 120 cygnets and 34 breeding pairs.

He said numbers did fluctuate but added: "Our expectations are that numbers should be better than last year."

Swans are counted at the start of annual census of the swan population

Mr Barber said the protected birds were "very easy targets".

"When they're shot, some don't get killed straight away - they go off and sometimes take a week to die and that's the awful part," he added.

David Barber looks at a swan and a cygnet

The census dates back to the 12th Century and sees the mute swans on the river rounded up, marked, weighed, health-checked and then released.

Mr Barber said it also served as a "very important conservation and educational exercise", with many local schools taking part in the event.

Swan Uppers negotiate Shepperton Lock on the river Thames

Some of the lowest numbers recorded in recent years were in the 1980s due to lead poisoning, Mr Barber said.

Flooding on the Thames cancelled a section of the ceremony in 2012.

A young Swan Upper holds a swan to be counted

The Crown retains the right to ownership of all unmarked mute swans in open water.

The Queen's Swan Marker holds a swan aloft during the Swan Upping ceremony

Killing or injuring them is punishable by a six-month prison term and, in some cases, a fine up to £5,000.