Birds Harvesting -- what?

The Canadian geese have been back for a few weeks. This year they arrive in gaggle of 8 to 15, browse the lawn for about an hour and take off. I assume they are stopping by here for a while, perhaps another month or so, until they go further south where snow is rare.

The last few days I have noticed this infestation [is that the word? seems right] of starlings -- a flock of several dozen that arrive in the late afternoon, and do not stay long. I watched them today, since it's Sunday and I was wracking my brain over the Times crossword puzzle as I sat on my mini-patio. They arrived from the north, settled in the middle of the sizable lawn [photo shows the south end which is less than a quarter of the entire lawn] they browsed for about five minutes then gradually individuals flew a few feet further south, others followed suit until the whole group had moved forward about ten feet, then they repeated that process a coupe of times until they reached the edge of the lawn, then some individuals [the leaders?] flew back ten feet north and the rest gradually followed, this was repeated a few time and then they were up and off as a group.

I don't know what they are eating, but they obviously are. Are there seeds from the grass or are there insects. I believe the geese actually eat the grass although they don't make an appreciable difference in its appearance except for their piles of droppings.

My botanical ignorance has been bothering me lately -- but not enough to do serious research. When I walk on the beach I watch the tiny sand pipers [or maybe baby sanderlings] running along at the very edge of the tide, pecking at something. I suppose it is small insects, what else is there? I can't see anything but they clearly find things that they eat. They are all fascinating, I think of Mary Oliver's line in her "Summer Day" when she says she has been watching a grasshopper which she describes exquisitely, and asks, "What else should I do?" Indeed.