The female has an orange bill, while the rest of her is solid light grey. In white zebra finches, the male and female are solid white, but the bill is still red in the males and orange in the females. And like canaries, only the male zebra finch sings. Young zebra finches have orange bills and have a more puff-like look about them. If they are very young, under three months, they will also have some black on the bill, and very young birds' bills are entirely black.
Budgerigars are probably easiest to sex when they reach maturity at six to seven months old.
The cere, which is the waxy skin around the nostrils above the beak, will either turn blue for a male, or tan or brown for a female. In babies, the cere is pinkish-purple, but looking at enough of them will give an idea of whether it will be male or female. The cere will have a more bluish hue for baby males and appear more white in females, although this is not always the case. Also observing young parakeets and looking for the ones that seem more talkative could also provide clues as to the males, but until the cere changes color, it is merely a guessing game. Very young parakeets, five to seven weeks of age, will have dark brown to black at the tip of their bill.