Written by Lucy Brzoska
Large numbers of Black redstarts (Phoenicurus ochruruos) move into Barcelona every winter, and some of them settle in Montjuic’s Camí del Mar (Sea Walk), a prime location. Where the castle wall forms a right angle and a palm tree with a fire-blackened trunk reaches the battlements, a handsome male has established his territory.
He’s often to be seen perching on the rubbish bin, scanning the ground for insects. Sometimes he briefly clings to the wall, with a flash of white wing patches, to pick a morsel out of its recesses. His front is dark and sooty. His back is slate grey with a faint hint of blue.
Another Black redstart presides over the grassy slopes by the small fig tree. Grey-brown, it could be a female or a first-winter male.
There are many theories for why the majority of young male Black redstarts stay mouse-brown and only moult into full adult finery in their second autumn. Suggested advantages include less attention from predators or aggressive rival males.
But some of the first-winter males have nearly managed to moult into full adult plumage first time round: they only lack the natty white wing panels, like this individual, who can be seen by the steps leading up to the castle draw bridge.
Regardless of sex or age, all Black redstarts have fiery red tails, which they constantly flick. They have an alert demeanour, bobbing up and down, reminiscent of a robin.
There’s an interesting study of Black redstarts and the phenomenon of delayed plumage maturation here.