There was nest of a hawk or eagle in the crotch of this Saguaro butwas empty.  It might be that no bird was occupying it, but also it could be that the crowds were spooking the birds and not able to nest.  I hate to think that eggs in the nest were not being attended to because of the crowds.

This is another shot of the saguaro with an empty nest. Somebody ought to have warned the birds that this would be a super bloom year and hence they would be plagued by flower children.