I went out looking for a Blue Heron again today, but there were none about. I didn't want to leave the woods completely empty-handed, so I snapped the shot below of some backlit leaves.
The sunlight is directly behind them, so it's quite a high-contrast edge...I peeped in at 300% but didn't see any black dots. I'm giving up on that.
I snapped the shot below near work, driving around at lunchtime.
And this one on my way home: