Bit of a mystery

Hello all,how are you?
I have a mystery in the garden..these appear to be eggs and are being laid on the trampoline net of all places..its the 3rd lot..the 1st batch i thought was bird poop and washed off..the 2nd and 3rd batch i have left to see what hatches..

Any ideas anyone..and has this happened to your trampoline?
ftm