Do you have deer or rabbits. Not sure what other wildlife you might have where you live. I know
@goldfinch4 (Chris) has had some losses similar to yours during winter. Voles can be a very big problem in some gardens. We have deer, rabbits, voles, gophers, squirrels, and even some of the birds will pull some colonies apart and scatter them.
When we constructed out beds we put 1/4" hardware cloth under the beds so burrowing rodents could not gain access. This photo was taken in 2013 when we started converting all the wooden beds to cement block.
