Magpie iridescence


Magpies do not favour this region because it is highly forested. These birds prefer open habitats with occasional clumps of trees. Consequently, there are few opportunities to capture pictures of magpie iridescence.

The pigmentation of a magpie’s feathers produces a plumage that is strictly black or white. Yet in some lightings, the black feathers on the wings and tail produce brilliant colours, particularly blues and greens. These colours do not result from pigmentation, but iridescence.

Cells in the iridescent feathers contain a basal melanin layer, which produces the black by absorption. Above are stacked reflecting platelets, which produce the iridescent colours when light reflected from one layer interferes with that from another. The resulting colours are bright, pure and strongly directional. A bird can use this for flashing a signal in one direction, while remaining inconspicuous to a predator in another direction. 

Of the handful of pictures of the Black-billed Magpie I have taken, only a few of them show the blue-green iridescence of the wings. In this picture, taken two days ago, the tail just looks black.

However, contrast that black tail with the brightly iridescent tail of the same bird seen a half-minute later. Who knows what signal it is attempting to send?


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7 Responses to Magpie iridescence

  1. Trevor Goward says:

    Thanks very much for this, Alistair.

    I hadn’t understood until now that the iridescence derives from a second layer superimposed over the black ground layer.

    As for the intended message, maybe this bird is returning your keen interest, as would be reasonable.

  2. Karen Pidcock says:

    Thanks for revealing the oft-hidden iridescent hues of this scrappy-sounding bird, which are actually quite strikingly beautiful!

  3. Stu Heard says:

    If these birds were to be seen in the tropics most of us would comment “what a beautiful bird”….but sadly in much of Canada we say “oh it’s only a magpie”….rethink is needed and Allister you have provided a perfect opportunity for that…..THANKS!

  4. Christine Boyd says:

    These are stunning photos! I haven’t seen a magpie since leaving Alberta many years ago.

  5. Eileen Delehanty Pearkes says:

    I have been watching an extended family of magpies in the open pastureland near Sunshine Bay. Their nests are as chaotic as their feathers are beautiful!

  6. Monique says:

    Here on the Palouse in Washington, they are emblematic of our open hills, criss-crossed by the shrubby riparian draws with hawthornes they love to nest in. They’re derided as pest birds by many – but I love them (and all corvids). Scrappy indeed, smart, funny – and gorgeous too! Most summers there’s a nest someplace near my back yard, and they seem to delight in harrassing/dive-bombing my 2 cats, to protect their youngsters (who are way out of reach, of course). The cats hide under tables and chairs, waiting grouchily for the teenagers to fledge…

  7. Len Jellicoe says:

    Hi Alistair- I haven’t visited your site for a while so I just spent some time going through your blogs. Some great stuff.

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