The pictures in the article show the difference of sunny vs cloudy days of pidgeons without macrophages. I would have prefered to see the comparison of pidgeon

The pictures in the article show the difference of sunny vs cloudy days of pidgeons without macrophages. I would have prefered to see the comparison of pidgeons with vs without macrophages on cloudy days. That might have required the removal of pidgeon's body parts, the liver?