OG259 如何翻译呢？

259. Five fledgling sea eagles left their nests in western Scotland this summer, bringing to 34 the number of wild birds successfully raised since transplants from Norway began in 1975.

(A) bringing

(B) and brings

(C) and it brings

(D) and it brought

(E) and brought

不知如何翻译此句，请nn们帮忙！

今年夏天五只小海鹞离开西苏格兰，因而使自1975年从挪威移育（野鸟）活动开始以来养育成功的野鸟数增至34只。

is there any "cause-and-effect" nauture of the situation?