Tuis are boisterous songbirds that can be found in New Zealand. Researchers found that these tiny birds can actually get pretty aggressive when another bird shows up with longer and more complex songs.
Tuis are medium-sized birds that can grow up to 30 centimeters long and weigh up to 125 grams for males and 90 grams for females. They have black legs and feet and look almost completely black from afar but actually have blues and greens on their feathers when seen up close.
Despite their size, they are actually known to be notoriously aggressive birds, especially when it comes to protecting their territory from rival tui or even other bird species. Naturally, they will defend their territory from rivals when they need to, but as it turns out, certain circumstances lead to more aggressive behavior.
According to a new research published in the Ibis International Journal of Avian Science, these small birds get aggressive when a rival male tui sings songs, which are more complex and intricate songs. Not that they don't protect their territory from birds with simple songs, but they evidently react more strongly to birds with complex songs.
Tui Response To Complex Songs
To test the responses of tui, researchers played recordings of different male tui singing songs with varying complexities as well as one control song from another species. The complex songs were almost twice as long and with twice as many syllables as the simpler songs.
What they found was that the tui reacted more strongly and aggressively to songs that are more complex compared to the simpler songs. When complex songs were played, the birds flew over quicker and got closer to the speaker. Specifically, the tui were merely 0.3 meters away from the speakers during long and complex songs compared to the 6.3-meter distance during simpler songs.
Further, they responded to complex songs with longer and even more complex songs of their own.
A Case Of Song Jealousy?
This isn't just a simple case of being jealous of their neighbor's talent. In the world of birds, songs often have two functions: territory defense and mate attraction. This is possibly because longer and more complex songs tend to show the birds' physical endurance and signs of vocal skill.
According to study author Samuel Hill, New Zealand has flowering and fruiting trees all year round, so tui likely have to consistently defend their territory. That said, it's possible that the tui's more aggressive response to more complex songs lies in their need to protect their territory from a possibly strong competitor.
Results of the study suggest that tuis are able to distinguish between simple and complex songs and perceive birds capable of singing complex songs as greater competition.