[The] soundest account of the general function which Miss Moore's birds and beasts perform in her poetry [is that] they provide the perspective through which to see our (and her) finally human world. Birds and beasts have, of course, performed such general functions in literature from the time of Aesop down to the time of Walt Disney. Miss Moore's use of them is a variant of this general function, for all that Miss Moore's variant is peculiarly her own.

It is, however, so peculiarly her own that the superficial reader may easily be baffled…. Confronted with, and perhaps overpowered by, the complex and edged detail with which the "vehicle" is treated, the reader may conclude that there is no "tenor" at all—that he is dealing, not with a metaphor, but with a thing presented, almost scientifically, for its own sake.

Yet, of all men, it is the...