The yard is full of these maple seedlings every spring. Unsure what the other one is.
The composter was full last fall, mostly of maple leaves. (It is now about 2/3 full.) Kitchen scraps have been buried in the leaves throughout the winter, and they are now starting to break down along with deeper, now slimy, leaves. Working to get the air in by weekly stirring. I didn't get a leaf bin made last fall, but we do have a heap next to the Earth Machine composter, plus some in bags, so we can add as needed throughout the summer.
Wait! Didn't I just find all those signs of spring? We were surprised by this the next morning, April 18!