@mcsiegle I got really wet waiting for it - it seemed that the birds liked the tree for some reason, and that one kept coming back.... but not so eagerly when I was standing there taking pictures. I outlasted it though! :)
@sarahdphoto Hi Sarah! It was an isolated tree, so there was a lot of white cloudy sky around it. When you do exposure metering on the whole frame like this, the dark parts end up looking more or less like silhouettes against that very pale open sky. The rest is just playing with sliders in post-processing - a combination of bumping up the blacks, contrast, and if needed highlights to brighten up the sky even more. You should try it - there are a lot of great silhouettes around. And on such grey and rainy days as we were having, these things are the main stuff I see when I get to photograph something.
Mandy - I just saw your picture and had to smile!!!!