Noisy miners are complex creatures. The Australian native honeyeaters are part of large, cooperative groups. They use alarms to identify predators and, occasionally, help to raise youngsters of miners. They’re probably most well-known for their coordinated and aggressive attacks against other birds, an act that’s known as “mobbing.”
We conducted a research study to determine certain factors that can influence mobbing. We wondered if the availability of human food on cafe tables or a high nectar source due to the plantation of gardens could provide urban miners with more energy and time to mob different species more frequently. We also looked into how miners behaved toward certain species than others.
The study was released in Emu-Austral Ornithology and found it wasn’t the cafes that had access to food with sugar that caused more aggression from miners. In reality, it was the gardens, the areas where we observed the greatest level of aggressive behavior.
Understanding mobbing is vital as it can cause other birds to flee and decrease the diversity. Smaller birds that have similar diets that noisy miners have are especially vulnerable.
Noisy miners could drive away other birds and diminish the diversity of birds. Photo by Mark Broadhurst/Pexels, CC BY
What we did
The most preferred habitat for noisy miners is on the edges of eucalypt forests, which includes areas of cleared land as well as urban fringes. Their number has increased in recent years, which is posing a serious conservation challenge.
We have learned from earlier studies that noisy urban miners are more aggressive than rural residents.
However, to study mobbing more thoroughly, we set up taxidermies in museums (stuffed animals) from different kinds of bird species in three distinct types of habitats within Canberra:
Urban cafes that have lots of food remnants
urban gardens with higher than usual amounts of nectar
the bush habitats are more like “natural” miner habitats.
We then presented the local noise-making miners with three types of taxidermy models for museums of birds:
Food competitors that have similar diets as miners, and both with the same size (musk lorikeets) and a lesser type (spotted pardalote)
Potential predators, such as the dangerous species that preys upon miners (brown goshawk) as well as a species that is known to steal nests but poses a lower danger to miners who are adults (pied currawong)
Neutral species, which means an animal that doesn’t hunt or rival miners for food (in our research, we made use of a model of an eastern rosella).
We wanted to know how miners reacted in response to the “intruders” in various settings. We also installed an audio speaker in the vicinity to make alarm sounds and observe how miners responded.
Noisy miners are famous for their ferocious as well as coordinated attacks on birds. The act is known as mobbing’. Shutterstock
What we discovered
We discovered interesting variations in the response of miners in response to the taxidermy model, as well as the alarms broadcasted.
Noisey miners showed aggressive behavior for longer periods in cafes and gardens in comparison to natural bush habitats.
Surprisingly, access to food that is high in sugar at cafes did not produce the most aggressive behavior. Instead, we observed the most aggressive behavior near gardens.
Plants that are rich in nectar (such as grevilleas, bottlebrushes, and others) attract birds that have an appetite for sweets, and miners aren’t an exception. The latest cultivars bloom for longer, and miners living in our gardens could be able to access an all-year-round supply of food.
Access to these blooming plants can increase the level of aggression, providing more energy, time, or a reward to loud miners fighting these extremely rich resources.
The kind of model used has also affected the miner’s response.
An area attracted the miners and began mobbing the subject for a longer period when the model was an animal predator.
Miners displayed more aggressive behavior towards models of food competitors. However, the miners are more likely to hit models of food competitors by swooping or pecking in comparison to predator models.