They aren't near the house though... I think the chickens must be weeding them out near the back door. Who knows?! I can't get rid of it for the life of me.
We also call goatheads, three cornered burrs, or sheep burrs.
We had them so bad when we moved to this place. We got some geese and there are no more burrs. They keep them down completely.
We are in the country. Ducks may do the same, I do not know. But geese will eat every little plant they find. The seed comes in from the roads in the tires of vehicles, so there is an ongoing supply if you do not have geese.
Southwind