You may have a female tree. It is usual (if your tree is a Kilmarnock Willow) to have the male form which produces the silky grey-white catkins with yellow emergent stamens in early spring but there is a female clone going around that unfortunately still gets passed off as the male form. This produces catkins of small carpels (seed pods when fully developed) and doesn't develop the yellow stamens. It is less attractive consequently. It might be these that have fallen?

Can you post a picture with something to scale?

thanks for everyones help ,i will endeavour to post a picture in the near future