The structure of the sonnet is Petrarchan, an Italian form of the sonnet that characteristically divides its theme into an octave, in which a problem or emotion is stated, and a sestet, in which the problem or emotional tension is resolved.
There is a clear separation between the first eight lines (the octave) and the final six (the sestet). The octave is divided into two four-line stanzas, or quatrains. The first quatrain opens with a recounting of the occurrence in mid-scene.It begins abruptly, as the swan assaults Leda with “a sudden blow,” which is most likely a reference to an act of sexual penetration. The use of that simple, powerful phrase (not a complete sentence) and a break before the line continues emphasizes the explosive violence of the act.
Line 1 continues with a description of the great swan hanging in the air above the girl with its wings beating. There is a pun on the word still; the bird’s wings continue to beat and are also still as it hovers above without moving.In line 2 there is a description of Leda that indicates her physical (and perhaps psychological) state, as she staggers under her assailant. The swan has its body over Leda as she falters under him; he caresses her thighs with his webbed feet.
There is an almost sensuous description in the phrase “her thighs caressed,” but this is followed immediately by the grotesque image of the swan’s “dark webs” in line 3 and the image of Leda’s neck in his bill as he holds her helpless against him.The swan is never referred to directly as a swan, but its presence is expressed in ordinary images like “great wings” and “dark webs” that in the context of the poem seem quite extraordinary. Leda is simply “the girl” who is caught in the bird’s beak like a small helpless animal. In line 4 the crushing movement of the girl pinned against the bird is reinforced by the repetition of the word breast as the two are joined together unwillingly.
