Insect and Spider Identification: Insect eggs (?) on backyard deck producing red discoloration , 1 by betulo

betulo wrote:
A week ago thousands of poppy-seed black round specks appeared on a patch of approximately two square yards on my deck. They had a gritty texture under the shoes, but I figured the rain would wash them out.

However, these eggs (?) started to burst, and left a patch of burgundy red on the slabs of the deck.

Concerned about permanent discoloration, I power-washed the deck a couple of days ago, and now they are back, as seen in the picture. Notice a leaf of a Prunus for size comparison, as well as the red color on the deck.

I don\'t know if these are insect eggs, or seeds, and whether the discoloration will fade by itself.