Two rare Portuguese tufted ducks have turned up in east London at Blackwall’s East India Dock Basin nature reserve for the second season running.

The pair arrived last week with markings on the beaks that were linked a nature reserve in Portugal.

The brown-feathered female turned up first, having been spotted earlier on a reservoir in Hertfordshire. The black-and-white male was seen on May 9, according to the Tower Hamlets biodiversity team.

“The ducks were definitely ‘an item’,” observed a biodiversity officer. “They travelled separately when they flew south last season and the same coming back, several days apart, but definitely seem to be together once they settled here.”

The ducks had been marked by scientists at Portugal’s Soa Jacinto Dunes nature reserve.

The nature reserve officials at Blackwall also reported a Red Kite making a rare appearance in east London flying up-river along the Thames.

The bird of prey with its distinctive dark red plumage and long fork tail was spotted by the biodiversity team, before being seen above Canary Wharf, then over the Tower of London. The nearest breeding and hunting ground is the Chiltern Hills 30 miles west.

Red kites became extinct in most of Britain in the last century after hundreds of years of being hunted as unwanted scavengers.

But they’re making a big comeback after a successful programme to reintroduce them in 1989, according to the Royal Society for the Protection of Birds which says the colonies in the Chilterns are now the most densely populated in Europe.