Sentence:  The methods employed to ascend to the nest of a bird of prey depend, in each instance, upon its site. If the nest is in a tree, a man can climb up and, having put the young ones in a basket, carry them home. If, however, the <WSD>eyrie</WSD> is built in the fissure of a lofty rock, a man is secured to the end of a rope and descends or is lowered from the rim of the mountain or cliff to the level of the hollow in which the eyrie is built and, entering, lifts the bird from the nest. 
Meaning of the word marked with <WSD> tags:  A bird of prey's nest.