Not brush strokes, just digital zoom.
I couldn't get close without spooking the birds, and I didn't have a camera on hand with optical zoom, but I figured I'd give it a shot with my phone.
It's not clear. But it is a great example of something I've found fascinating about digital zoom: The way it can make a photo look like it’s been painted with brush strokes rather than captured with pixels.
No, those aren’t brush strokes. It’s just digital zoom.