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How to determine the sex of a lovebird
Give your lovebird a physical exam.
If you are just curious about the sex of a lovebird, and are comfortable with the possibility of being wrong, a physical exam can give you some clues. For example, feeling the distance between the pelvic bones can help you determine the sex.
Female lovebirds need more width in the pelvic region in order to pass eggs through it. This means that you may be able to determine a male from a female by comparing the width of several lovebird's pelvic bones.