A rook, with its coat of many colours

 I'd always thought of rooks as birds with uniform black plumage, until this one landed in a tree outside my window and the early morning sun highlighted the iridescence in its feathers, particularly around its head. Look closely and you can see a blue, purple and green lustre, depending on the angle of the light.

Cormorants' coat of many colours

Thursday's Guardian Country Diary is about cormorants.

Look at a cormorant's plumage from a distance and it seems as though it's coal-black, but a bit of sunshine makes all the difference.

Bright sunlight glancing off their outstretched wings reveals a bronze iridescence ...




..... but in a more diffuse light there's indigo in the chest and wing feathers....






.... while this juvenile has a hint of bottle green in the crown and tail plumage.

All 'a trick of the light'.

Iridescence

Two lovely examples of iridescent colours seen today..........

... the subtle pink and green highlights in the mother-of-pearl layer of a top shell, picked up on the beach at Whitburn this afternoon. Abrasion by sand has worn away the outer layers of the shell, exposing the lustrous nacreous layer underneath.....

... and the more vibrant iridescent greens and blues of the plumage of the magpie that come to drink at our conservatory gutter every morning ....

For magpie feathers under the microscope, click here