This is not at all a surprising find. Cordilleran/Pacific-
Slope Flycatcher haters might be interested to know that there
are (apparently) differences in plumage color in the near-
ultraviolet for that complex.

Most insect species also have the capacity to see in ultra-
violet as do some lizard species.

>From Gill's _Ornithology_
"Unlike humans, birds are sensitive to light in the near-
ultraviolet spectrum. In the human eye, the lenses absorb
ultraviolet light; in birds, they transmit ultraviolet light
to the retina, where some cones have peak sensitivity in
the near-ultraviolet spectrum (Chen et al. 1984). Melvin
Kreithen and Thomas Eisner (1978) demonstrated that homing
pigeons, in addition to having the normal vertebrate
sensitivity to blues and greens (at 500 to 600 nanometers),
are sensitive to the near-ultraviolet spectrum (325 to 360
nanometers). Also tested recently were Black-chinned
Hummingbirds, Belted Kingfishers, Mallards, and several
passerines, all of which are sensitive to ultraviolet light
(Goldsmith 1980; Parrish et al. 1984). Given the taxonomic
diversity of those species tested, the majority of birds
probably possess this trait.

"The richness of avian color perception is probably beyond
that of human experience (Goldsmith 1980). We speculate
that primitive mammals, including the ancestors of primates,
were nocturnal creatures that lost the retinal oil droplets
associated with sensitive color vision. Once lost, these
droplets did not evolve again in placental mammals. Instead,
the color vision of humans and other primates was reevolved
on a different basis without pigmented oil droplets. Very
likely, the avian retina?with its high cone densities, deep
foveae, near-ultraviolet receptors, and colored oil droplets
that interact with several cone pigments?is the most capable
diurnal retina of any animal."

> A study came out a number of years ago that showed that the Blue Tit, a
> European species always thought to be sexually monomorphic, shows
> obvious sexual dimorphism in the ultra-violet range. The birds
> presumably can see the difference, but our human eyes can't. It would
> be interesting to know how common this is in birds.
>
> Rachel Lawson
> Seattle
> RachelWL AT msn.com

--
Mike Patterson
Astoria, OR
celata at pacifier.com

Yes, I'm sure, but I still don't think I'll count them
http://www.surfbirds.com/blogs/mbalame/archives/004476.html