Nothing like a birdbath to highlight the difference between males and females. I have a little backyard garden at my studio that I enjoy all day through a sliding glass door next to my desk. I maintain this little ecosystem for my distraction, plus it's a constant source of fresh images. Why drive to the mountain when its habitants will come to you?
One of the features in my own private Eden is a makeshift birdbath. It's heavily used, so I change the water daily and keep it shallow because, well, the birds like it that way. Just like with any creature you observe daily, you get to know their habits and quirks. In this case, the difference between some males and females.
The female in the top photo was very lady like as she bathed her feet and freshened up. The male, on the other hand, just bent over and stuck his head in the drink. I'm sure he burped afterward too.
Both images captured with a 5D Mark II and a 70-200mm f/2.8 IS L zoom. The female shot was tethered to a MacBook Pro (located behind the curtain) running EOS Utility. The shot of the male... just handheld. He wasn't nearly as shy. You can click on either image to enlarge.