If You Think That's Big, You Should See the Nest

Nest building is not limited to only springtime for ospreys.  They are opportunists and, if one sees a good branch floating by, it will retrieve it and take it back to the nest.  I have also seen males bring new branches to the nest while young were in the nest being cared for by the female.  Anyone who has seen the ground underneath an osprey nest knows they are not particularly skillful at actually getting branches into a nest.  I saw one attempt one time where the male clubbed the female with a branch and she thought it best to leave the nest for a while.  With them, nest building is a year-round task - at least until they migrate south for the winter.