Sentence:  [...] the usurper Buljan ordered that his sukkah be erected on the donjon's roof, with its [...] relative nearness to the stars, among which his sky-worshiping and uncircumcised ancestors still hunted with infallible <WSD>gyrfalcons</WSD> for celestial game. 
Meaning of the word marked with <WSD> tags:  "Falco rusticolus", a large bird of prey that breeds on Arctic coasts and islands of North America, Europe and Asia.