Full of attitude

You have to admire how plucky Blue Tits are. For such a small bird they have a great attitude.

Humans think it’s difficult to tell the difference between male and female Blue Tits because their plumage appears identical. Blue Tits, however, have no problem telling the difference. They can see clearly in the ultra-violet part of the spectrum which is invisible to us. Male Blue Tits light up like a beacon in ultra-violet, with an intensely bright crest.

I wonder which this is?

I wonder how many other birds appear completely different in a part of the spectrum of light that they can see and humans can’t?