Thursday, January 12, 2017

Purple or green?

The male mallard has an iridescent green head.

Mallard, Campbell River estuary. Against the light, so the glow of the head is muted.

And sometimes, a purple head.

This one is half purple, half green.

I looked for an explanation of the colour shift, and found various theories:
  1. It's due to interbreeding with other species. And mallards are notorious for this.
  2. It's really just green, but it looks purple because of light interference and diffraction.
  3. Some mallards are just purple-headed. That's it. And why not? Just enjoy!
  4. The colour depends on the structure of the feathers.
An interesting discussion follows this photo of a strongly purple-headed mallard on Flickr. I have no theory, other than #3 above.

While we're on that shore, here's a sparrow, not shiny, not showy, but just happy, bouncing around in the weeds along the bank, finding goodies to eat.


Lots of yummy seeds among that broken, dried grass!


3 comments:

  1. I've noticed that people who live near the ocean see lots more birds than we do up the lake this time of year. It must be that there are more abundant food sources there than along a deep lake surrounded by forest. - Margy

    ReplyDelete
  2. https://thenatureniche.com/2013/03/18/blue-headed-mallard/

    this post has some insight to chemical levels in the males

    ReplyDelete

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