This is a little surprising - the leaf damage is caused by leaf-cutter bees - they use the pieces of leaf to line nests they make, typically in holes in wood. I wouldn't expect them to be up as high as the 14th floor, though. Watch for bees that look a bit like small honeybees, but usually darker. They shouldn't cause any lasting damage to your plants, and give you an opportunity to observe a very interesting bit of nature in the city. Check the link below.

Tucker

Here is a link that might be useful: Leaf-cutter bees

I am thrilled to know this. Nature persists! This terrace is not only on the 14th floor, it is right on the edge of Times Square.

Yes, now I recall seeing some of these little bees, though I didn't see them cutting leaves. I looked for a possible nest. There is no wood at all on this terrace -- only stone, some metal facings, ceramic tiles, bricks, wrought iron railings, steel window frames. Mosses and grass and some little weeds grow between the tiles.

Obviously the critters have found a cozy spot -- I will continue looking. Thank you so much for this!

Beth

Only the female bees do this, and they are solitary, excavating rotted wood or using existing inches-long small voids in walls or other structures.

It is possible your particular bee is done for the year.

Thank you Larry, that's good to know. I will look for the burrow. And track them again next year.