"This Backyard Bird Has a Lot to Teach Us about Sex Variability"

[mrbigstuff]

Interesting. But also

"This interesting and complex situation has earned this species the nickname “the bird with four sexes.” But to be clear, White-throated Sparrows do not have four different types of gonads. As in other birds, each individual typically has either two testes that produce sperm or a single ovary that produces eggs."