One of the blessings of being required, by the terms of my ongoing cardiac rehab, to keep walking... no matter what... is that I'm constantly encountering new sights, sounds, smells, and, well, experiences with the natural world. Of course, these terms are rather explicit about having to keep moving forward and keeping my heart rate elevated, but sometimes I'll throw caution to the winds, stop for a little while, and take out the camera I always carry with me to record what I've discovered. It's probably not heart healthy, but, then again, neither is spending any time regretting what I failed to do. So, since I'd already walked four miles when I noticed a sparrow happily perched on the back of a Holstein, I paused for a photo shoot. This is not, however, the same kind of scene you'd see in Africa, where birds known as oxpeckers hang with cattle to glean invertebrates from mammal backs, or, occasionally, lap blood from cuts the oxpeckers inflict in pursuit of prey. Here, I think the sparrow is just going along for the ride.