I thought that Dante's choice of birds in Canto V was strange. Why would cranes, starlings, and doves-- generally symbols of peace and joy-- represent categories of the lustful? Why would Dante place these particular birds in hell?
Firstly, Dante describes the mass of unidentified souls in the circle of lust as starlings. These birds travel, or band, together in flocks of up to several thousand. As they migrate, they contaminate agriculture with their droppings and practically black out the sky in some areas. Dante's choice of starlings makes more sense knowing this. Symbolically, the birds, as a mass, block out the sun-- knowledge, salvation, or God-- and destroy agriculture-- the sustenance of life- or virtuous love. Dante views idealized love as the way to salvation and the purest form of human expression when it is moral and true. These birds, known to disturb human life by ruining food (love) and blocking out the sun (God), are a fitting symbol to characterize the mass of lustful souls who, in their actions, tainted the sustenance of life, love, and turned away from the light, God.
Next, Dante observes a line of cranes. These birds represent famous lovers. The crane presents somewhat of a paradoxical symbolism. While it is considered one of the oldest birds on Earth-- appropriately corresponding with their representation of lovers from antiquity-- they are also common symbols of peace and prosperity. According to Roman and Greek mythology, cranes symbolized "a love of joy and a celebration of life" (Legend of the Crane). They also generally stood for the god Apollo, the sun god. In much of Asia, the crane stands for "happiness and eternal youth" (Legend of the Crane) and love. However, Dante presents them in much the opposite light. It appears that he almost mocks the stigmatized meanings of these birds. Instead of representing eternal youth, they live in eternal hell. Instead of meaning love, they are the incarnations of love gone wrong. Perhaps, Dante means to create a paradox between the bliss of lust and the reality of hell. Though the lovers felt like they were eternally joyful in life, they suffer forever.
Finally, Dante refers to Francesca and Paolo as a pair of doves. This symbol confounded me the most. How could he represent these characters that he clearly felt deserved to be in hell as doves-- symbols of peace and love and holiness? Dante was a Catholic. He knew the significance of doves within the Christian religion as "a symbol of innocence, gentleness, and affection" (Dove Christian Symbol). Like the cranes, however, he creates a paradoxical view of the birds to show the backwards nature of the lustful. His doves, Francesca and Paolo were "innocently" reading a love story, "gently" ended up kissing, and eventually developed into a pattern of "affection" which led to their deaths. While the doves represented these good things, the lustful characters like Francesca and Paolo contorted them so they were exactly the opposite of what the characteristic dove stands for. Their love is not love, it is lust-- a blemish which Dante can hardly overlook.