A grey heron trapped in Thames mud on National Bird Day was rescued by the RSPCA after boat owners noticed it struggling with an injured leg.

The Embankment Marina in Gravesend is home to at least three of the predatory wading birds, which fish mostly at dawn and dusk.

Residents were surprised to see one standing on a buoy in the middle of Sunday, drawing attention to another one laying in the mud against a wall.

Witness Alan Carr said: "I went over to the path above to see if it was alive.

"When I got there it began trying to move away but didn't get far as it was dragging its leg behind it and was covered in mud.

"It had no chance of flying or helping itself so I called the RSPCA."

Due to high demand, the animal charity was unable to get there until 8pm.

After rescuing it, animal collection officer Emma Byrne confirmed the heron had broken its leg.

She explained the birds are usually territorial and the injured limb could have been due to conflict.

Grey herons are unmistakeably tall, with long legs, a long beak and grey, black and white feathering.

They can stand with their neck stretched out, looking for food, or hunched down with their neck bent over their chest.

The creatures can be seen around any kind of water – garden ponds, lakes, rivers and even on estuaries.

Sometimes, grey herons circle high up into the sky and can be mistaken for large birds of prey.

Mr Carr added that he was glad the creature had been rescued and would hopefully survive.

For information about the RSPCA, or to report an incident involving an animal call 0300 123 4999 or visit www.rspca.org.uk/home

Escaped animals, unusual finds and news from the RSPCA can all be found here.

Read more: All the latest news from Gravesend