THE annual tally of the swan population on the River Thames is now under way.

Queen’s Swan Marker, David Barber, is leading his team up the waterway all week.

They were due to set off from Sunbury Lock this morning, south of Heathrow, and will end the count in Oxfordshire on Friday. 

PICTURES: Last year's swan count comes to an end in Abingdon

The centuries-old tradition sees the upping team collecting data, dressed in their distinctive red outfits, assessing the health of young cygnets and examining them for any injuries.

According to ancient English law, by prerogative right, the British Crown enjoys ownership of all unmarked mute swans in open water.

The count will finish at Abingdon Bridge on Friday, July 19 at around 5pm.

It will also pass through Moulsford, Benson Lock, Clifton Hampden Bridge and Culham Lock on the same day.

Here is a full list of timings, according to the Royal Swan Upping website: 

Monday, July 15
Sunbury 09.00 - Departure point
Shepperton Lock 10.15
Penton Hook Lock 12.30
Romney Lock 17.30

Tuesday, July 16
Eton Bridge 08.30 - Departure point
Boveney Lock 09.15
Boulters Lock 12.30
Cookham Bridge 13.30
Marlow Lock 17.30

Wednesday, July 17
Marlow Bridge 09.00 - Departure point
Hurley Lock 10.30
Hambleden Lock 12.00
Henley Town 13.15
Marsh Lock 15.30
Shiplake Lock 17.00
Sonning Bridge 18.00

Thursday, July 18
Sonning-on-Thames 09.00 - Departure point
Caversham Lock 10.15
Mapledurham Lock 12.00
Goring Lock 17.00
Moulsford 18.00

Friday, July 19 
Moulsford 09.00 - Departure point
Benson Lock 10.00
Clifton Hampden Bridge 13.00
Culham Lock 16.15
Abingdon Bridge 17.00