( ( ( ( ( ( Human actions ) ( have ( caused ( ( the extinction ) ( of ( hundreds ( of ( species ( of birds ) ) ) ) ) ) ) ) ) , ) and ) ( ( some ( 1,200 species ) ) ( are ( ( threatened ( with extinction ) ) today ) ) ) ) . )
(ROOT (S (S (NP (NNP Human) (NNS actions)) (VP (VBP have) (VP (VBN caused) (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))))))))))) (, ,) (CC and) (S (NP (DT some) (CD 1,200) (NNS species)) (VP (VBP are) (VP (VBN threatened) (PP (IN with) (NP (NN extinction))) (NP (NN today))))) (. .)))
Human actions have caused the extinction of hundreds of species of birds, and some 1,200 species  are threatened with extinction today.
(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))))) (. .)))