( ( ( About one-quarter ) ( of ( all ( bird species ) ) ) ) ( ( are ( extinct ( as ( ( a result ) ( of ( human actions ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (RB About) (NN one-quarter)) (PP (IN of) (NP (DT all) (NN bird) (NN species)))) (VP (VBP are) (ADJP (JJ extinct) (PP (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (JJ human) (NNS actions))))))) (. .)))
About one-quarter of all bird species are extinct as a result of human actions.
(ROOT (S (PP (IN Around) (NP (CD 1200))) (NP (NP (NNS species)) (PP (IN of) (NP (NNS birds)))) (VP (VBP are) (ADVP (ADVP (RB currently)) (PP (IN at) (NP (NP (NN risk)) (PP (IN of) (NP (NN extinction)))))) (ADJP (JJ due) (PP (TO to) (NP (JJ human) (NN activity))))) (. .)))