What you see is what you get

[John Chardine]

The head angle for an optimum bird portrait is one thing, but what about what the birds see? When individuals interact socially either to fight or prepare to mate or whatever, they generally look directly at each other. When I capture an image of a bird's head, face-on, I am often impressed with the patterning- this is the species and sometimes sex-specific signal that one bird is giving to another. To illustrate this I've chosen a recent face-on image I made of a Bohemian Waxwing (Bombycilla garrulus) at Sheffield Mills, Nova Scotia.

Take a look at some of your images, in particular the ones face-on. Study them, and don't throw them away!

Other examples welcome!

[Rich Williams]

I like this. I can see this as an abstract artwork. Great detail too.

[Jackie Schuknecht]

Beautiful colours and details John. Does make you wonder what they see. Don't know what there field of vision is or if he even sees you???

[William Malacarne]

Does make you wonder what they see.

Here is a good article about how they see.

http://www.associatedcontent.com/art...ds.html?cat=53

or

http://is.gd/hXtx

Bill

[Judd Patterson]

This is really great John! I love how different this species appear with a direct view like this. Thanks for bringing it to everyone's attention...I'll try to pay closer attention to this.

[Jackie Schuknecht]

Thanks William, I will be reading this shortly!

[Dave Phillips]

excellent post/image John....I have often looked at this view without giving much thought

[Joerg Rockenberger]

Wow. Indeed a very interesting perspective. When I try to abstract I see a spider body with huge fangs...

JR

[John Chardine]

This is a fun one!

Here's a couple more examples from two closely related species. These patterns are meant to be seen face-on. Top is White-throated Sparrow (Zonotrichia albicollis) and bottom is White-crowned Sparrow (Z. leucophrys). Notice how the white blase on the throat of the WTSP is framed in black, presumably to accentuate the effect. Although these species-specific patterns are clearly different, occasionally mistakes are made and hybrids are produced.

[Declan Troy]

At the risk of going off on a tangent let me throw out that many birds (including Bohemian Waxwings) that appear sexually monochromatic are actually dichromatic when you consider UV wavelengths that birds can see but we can't. That waxwing face would look very different to another waxwing. Anyone with a UV camera out there?

I'm unsure of the UV status of White-throated Sparrows but they come in two plumage polymorphisms, white and tan, that occur in both sexes and pairing usually occurs between opposite color morphs. These color morphs also differ in behavior and chromosomal inversion. The chromosomal polymorphisms occur in several other sparrows (I forget about white-crowned) but so far no simple plumage characters to go by.

Declan

[John Chardine]

Very interesting point Declan. Do you have a reference for the sexual dimorphism in plumage at the UV wavelengths. I'd really like to read more about this.

[Declan Troy]

Here area a couple to get you started. You likely have one on your shelf. The PNAS one is available online and you likely will want the supplemental materials (to see details for Bohemian Waxwing).

Eaton, M.D. 2005. Human vision fails to distinguish widespread sexual dichromatism among sexually ‘‘monochromatic’’ birds. Proc. Natl. Acad. Sci. 102: 10942-10946.

Eaton, M, D. 2007. Avian visual perspective on plumage coloration confirms rarity of sexually monochromatic North American passerines. Auk 124 (1): 155-161.

Declan

[John Chardine]

So now we have to change the Subject of the thread to "What you see is what you don't get!" Thanks to Declan for these very interesting papers. To summarise (and this is not my field of expertise):

- much the same as insects, birds can see into the UV end of the spectrum much better than we can
- it turns out that birds that look alike to us (monomorphic)- say males and females of certain species that look identical- often aren't in UV light (i.e., they are sexually dimorphic)
- this is going to have to require a rethink of the issue of sexual dimorphism in birds. It has been long thought that many species of birds are sexually monomorphic because most birds are monogamous (one male mates with one female). In monogamous species, sexual selection that causes things like males to be bigger and/or showier than females is weak or non-existent so males and females look the same. But now we know they don't.
- Genetics work has shown that monogamy in birds is only apparent in many species, and that males and females of many species "sleep around". This may mean that sexual selection is in fact a lot stronger in many species of birds than we thought, and that sexual dimorphism would be more common. It's just that we can't see this dimorphism because it's in the UV.
- the other area that this work affects is the whole issue of species and species recognition. Our classification system for living things relies heavily on differences that we can see between individuals. We now know that with respect to birds, what we see is not necessarily a reliable indication of what birds see, so there could be a lot more species-level differences out there between populations that we are unaware of because we simply can't see it.