Usually when I assemble a puzzle, I begin by filling it in from the edges. I couldn’t do that in this one because of the sheer number of pieces, therefore I’ve been creating several floating areas and connecting them to each other\the edges. It’s not always obvious how they connect, though, and more than once I had problems because things were misaligned and I kept trying to fill gaps that shouldn’t actually exist.
This is easier to solve now that I can check the repeated patterns of pieces. Today we realized the puzzle was out of alignment again — sort of a trapezoid instead of a rectangle — because one of the repeated sets couldn’t fit anywhere (it’s hard to see in the picture, but basically the part with the storks was very tenuously attached to the rest and, as it turn out, in the wrong way).