( ( Hundreds ( of ( species ( of birds ) ) ) ) ( ( have ( ( gone extinct ) ( as ( ( a result ) ( of ( human actions ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Hundreds)) (PP (IN of) (NP (NP (NNS species)) (PP (IN of) (NP (NNS birds)))))) (VP (VBP have) (VP (VBN gone) (ADJP (JJ extinct)) (PP (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (JJ human) (NNS actions))))))) (. .)))
Hundreds of species of birds have gone extinct as a result of human actions.
(ROOT (S (NP (NNP Human) (NNS actions)) (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (NP (NP (DT the) (NN extinction)) (PP (IN of) (NP (NP (NNS hundreds)) (PP (IN of) (NP (NP (NNS species)) (PP (IN of) (NP (NNS birds))))))))))) (. .)))