There is a certain possibility
        that birds are weightless
                or else...the branches
                     are stronger than they look !

   Have you seen...when a bird hops on
              to a top thin branch.....
                  at first the branch almost gives in !
                          Then...strangely...the branch holds up !!!

          There seems to be  another posssibility:
                         a fact that might be true !

              ...that the tree is always in the know !
                     it possibly sends some  new strength to the branch...
                              ....and the birds too....seem to be aware of this !!!