![Illustration showing the difference between male and female huia](http://static.sciencelearn.org.nz/images/images/000/005/298/full/ART_Huia_Huia_Buller_PD.jpeg?1697677487)
The male and female huia had a distinct difference in their beak morphology. The female had a longer curved beak and the male a shorter beak as shown in this illustration.
Huia (Heteralocha acutirostris): male and female by Johannes Keulemans, from the book A History of the Birds of New Zealand by Sir Walter Buller.