Photo source: Tom Ingram Photography
The Great Hornbill reaches maturity at year 5 and the young males and females now mature begin the process of choosing a mate. This happens mostly when it is coming close to the new nesting season and hormones are on overdrive for the newly mature males and females. The training through play learned and practiced during its bachelor and bachelorette day will now take a more serious mode.
I have observed in the field where in a flock of 26 young birds, 3 newly mature males are fighting each other for this one particular female. With their large bills these 3 male clash like knights with heavy swords, sometimes even pushing each other off he branch sometime using their bills like lances and jousting in mid flight with one another.
Photo source: Neatorama
These 3 males carry several fruit in their throat pouch, ejecting a single fruit at a time to the end of their bill, pushing the other males out of the way for the opportunity to be the only male to offer her fruit. She knows how to find her own fruit but when it comes close to the nesting season and time to choose a mate she will initially accept fruit from all three males.
Eventually she will make a choice, she does this by collecting the fruit only from the male she wants, and when the other 2 male still try to offer her fruit, she on longer accepts it from them. Hornbills are monogamous and will pair off for life.