Want noisy miners to be less despotic? Think twice before filling your garden with nectar-rich flowers

Loud miners are complicated creatures. These Australian honeyeaters live in large cooperative groups, using alarm calls to attack certain predators and sometimes helping to raise other miners’ young. However, they are perhaps best known for their aggressive and coordinated attacks on other birds – a behavior known as “bullying”.

We conducted a study examining some of the possible factors that influence bullying. We were interested in whether having access to human food on plates in cafes or a high nectar supply from planted gardens could give urban miners extra energy and time to raid other species more frequently. We also examined whether miners were more aggressive toward some species than others.

Our study, published in the journal Emu—Austral Ornithology, found that it wasn’t cafes with access to high-sugar foods that led to more miner aggression. In fact, it is in gardens that we have found the most aggressive behavior.

It’s important to understand bullying, as this behavior can drive other birds away and reduce diversity. Smaller birds with a similar diet to noisy miners are particularly at risk.

What we have done

The noisy miner’s preferred habitat is at the edges of open eucalyptus forests, including cleared land and urban fringes. Their numbers have increased in recent decades, which poses a significant conservation issue.

We know from previous research that urban noisy miners tend to be more aggressive compared to rural populations.

But to examine bullying behavior more closely, we placed museum specimens (stuffed animals) of various bird species in three different types of habitats around Canberra:

• urban cafes with lots of leftovers
• urban gardens with above-average nectar supplies
• Bushy areas more typical of miners’ “natural” habitat.

For each habitat, we then presented three different types of museum-quality taxidermy models of birds to the local noisy miners:

• Competitors for food, with a similar diet to miners, both of the same size (musk lorikeet) and a much smaller species (spotted pardalote)
• potential predators, including a dangerous species that preys on miners (brown goshawk) and a species that robs nests but poses a lower risk to adult miners (spotted currawong)
• neutral species, i.e. a bird that neither hunts nor competes with miners for food (in our study we used a model of an eastern rosella).

We wanted to see how miners reacted to these “invaders” in different environments. We also placed a speaker nearby to send out alert calls to see how miners are responding.

what we found

We found interesting differences in how miners responded to our preparation models and the alarm calls emitted.

Noisy miners displayed aggressive behavior much longer in gardens and cafes than in natural bush areas.

Surprisingly, however, access to high-sugar foods from cafes did not result in the most aggressive behavior. In fact, we recorded the highest levels of aggressive behavior around gardens.

Nectar-rich plants (like grevilleas and bottlebrushes) are attractive to those with a sweet tooth, and miners are no exception. Newer varieties flower longer, meaning miners living in our gardens may have access to an almost year-round food source.

Easy access to these flowering shrubs can affect aggression, buying more time, energy, or rewards for noisy miners defending these bounty resources.

The nature of the presented model also affected the reaction of the miners.

If the model was a predator, more miners would be drawn to an area and harass the subject longer.

However, miners showed even greater aggression towards food competitor models. They were more likely to physically attack competitor models with a pick or punch than predator models.

What can gardeners do with these insights?

Our research shows the importance of considering how gardens—whether in backyards, in parks, or in new housing developments—can affect local ecosystems, including bird behavior. Previous studies have linked the types of plants that people plant to the local mix of bird species.

To reduce the risk of creating a perfect habitat for despotic miners in your yard, aim for the following:

• Plant tiered tiers in your yard – that means including ground covers, small shrubs, medium-sized shrubs and trees to provide shelter for different birds and animals at different heights
• consider planting lots of dense shrubs with small flowers to attract insects and provide shelter for small birds
• Use a mix of nectar-rich and non-flowering shrubs and grasses (rather than focusing too heavily on flowering plants)
• Try to avoid planting too many exotic species; Instead, opt for native plants that are native to your area and adapted to the climate, as these will benefit native plants and animals while minimizing the benefits to aggressive, noisy miners.

This article was republished by The Conversation under a Creative Commons license. Read the original article.