Sunday, January 25, 2009

On a grey day, all the colours

It was a good thing we'd started on our way to Reifel Island early; with a stop for lunch, and all the stops in between to look at birds, it was well past 2:00 when we arrived at the parking lot, barely 2 hours before sunset.

The mallards were out in force, some in the parking lot, more along the first part of the pathway, where new visitors would have fresh bags of grain. I dispersed a mere handful, though; I had other customers in mind.

Kid contemplating mallards.

Mallard with orange belly.

Between the office and the first crossroads, the LBBs (no-name brand: Little Brown Birds) set up shop. In the summer, the feeders are kept full; this week, they were all completely empty. But the scrubby bush there is full of food; dried blackberries in abundance, full heads of weed seeds, dried grasses, holly berries, and more. The birds chirp and sing happily in the tangle of stalks.

I tried to entice them out with my bag of grain, without much luck. We managed to get blurry photos of brown -- somethings -- before they hopped back into hiding. Oh, well; the ducks would get the bait instead.

A few LBBs, however, sat on the fence, and even stayed put as we took photos.

All puffed out against the cold.

House sparrow.

Golden-crowned sparrow in the blackberry canes.

We turned into the paths bordering the waterways. Now, the predominant birds were ...

... mallards, of course.

But there were a fair number of pintails:

... wigeons:

... coots, mergansers, and a few shovellers. We saw no geese, which surprised me.

Laurie got this photo of a male bufflehead, in all his female-luring glory:

I've always thought of buffleheads as black-and-whites, but when I looked at the photo, I noticed the sheen of blue on the head, and saturated the colours a bit more, just to see what they were. Here's what I came out with: (Click on it for a large copy, to get the full impact.)

Black and white. And blue, green, and burgundy.

I wondered; what do the females see? Do their eyes pick up all this display of colour? How much are we missing of the scenery here at Reifel?

Back to Google. I found this page: Causes of Color - Color Vision in Birds.
Only recently have we begun to grasp that vertebrates such as birds and fish possess more sophisticated color visual systems than we do. While we are trichromats, having photo-pigments with sensitivities at three peak wavelengths, birds have photo-pigments with sensitivities at four or five peak wavelengths, making them true tetrachromats, or perhaps even pentachromats. In some species, the visual spectrum extends into the ultraviolet range, once thought to be visible only to insects.

It is as hard for us to imagine how birds perceive color as it is for a colorblind person to imagine full color vision; it is outside of our experience. This impacts the study of bird behavior, and our grasp of how birds navigate during migration, classify objects, and interact socially and sexually. For example, some species we see as having identical male and female plumage differ when seen in the ultraviolet range - a difference apparent to the birds themselves.
Wandering through discussion groups and GoogleImages, I learned that some birds glow under ultra-violet lights. The males only, at least in some species. And the females pay no attention to them if they are somehow prevented from seeing the UV. (Sunglasses?)

From Wikipedia:
Some animals can distinguish colors in the ultraviolet spectrum. The UV spectrum falls below the human visible range. Birds, turtles, lizards, and fish have UV receptors in their retinas. These animals can see the UV patterns found on flowers and other wildlife that are otherwise invisible to the human eye. ...

UV and multi-dimensional vision is an especially important adaptation in birds. It allows birds to spot small prey from a distance, navigate, avoid predators, and forage while flying at high speeds. Birds also utilize their broad spectrum vision to recognize other birds, and in sexual selection.
Something to mull over. Something to think about in these grey days; maybe we are surrounded by unseen, unimagined rainbows.

Maybe not so dull, after all.

And here's a rainbow, even for our limited eyes: the male wood duck.

Handsome pair.

On our way back to the car, I stopped off at the washrooms. And while I was there, I checked out the swallow's nest at the side of the building.

Still there, still in good repair. I'll look for violet-green swallows there this spring.

I wonder how many colours they really wear.


  1. Wonderful post! and so full of thoughtful observations. The bufflehead photo is fun one. Thanks for the research on a bird's view of color!

  2. Very few birds stay around our cabin this time of year. We also have some LBBs, I tried to identify them with my books but wasn't sure either. - Margy

  3. Great post..loved all the information.
    I have never seen a yellow crowned sparrow..
    Great birdie photos

  4. Margy; the LBBs are impossible. I have a small flock of sparrows, of assorted patterns and sizes, in my backyard. I can distinguish the white-crowns, but the rest never quite look like any specific book description.

  5. Awesome post Susannah! Great bird captures and the information is wonderful.

    I did some checking last year on bird vision when I was wondering whether the brightly colored (usually yellow) gape of baby cavity nesting birds made it easier for the adults to pick out a specific chick's mouth to feed.

    I discovered a report by the UK's Royal Society where they found that the gape and surrounding flanges of the chick’s mouth was considerably brighter in the UV spectrum in cavity nesting birds than birds that nested in areas with more light.


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