Alien vs. Predator: Impacts of Invasive Species and Native Predators on Urban Nest Box Use by Native Birds

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• Native Australian birds rely on tree hollows for breeding.
• Urban development reduces natural nesting sites, increasing reliance on artificial nest boxes.
• Understanding factors affecting nest box use and success is crucial for effective conservation.

Purpose of the Study:

• To assess the impact of habitat, invasive species (common myna), and native predators on urban nest box use and nesting success of native birds.
• To evaluate the effectiveness of nest boxes in supporting native bird populations in urban environments.

Main Methods:

• Installed 216 nest boxes across nine sites in southeastern Australia over two breeding seasons.
• Monitored nest box occupancy weekly by all species (birds and mammals).
• Recorded nesting attempts, species, and nesting failure rates.

Main Results:

• Common brushtail possums (native) were the most frequent occupants (92% of boxes).
• Invasive common mynas made the most nesting attempts (72), but did not evict other species.
• Possum occupancy negatively correlated with native bird nesting success (p = 0.021), with an overall 53.3% nesting failure rate.

Conclusions:

• Nest boxes may not significantly improve nesting opportunities for native birds when accessible to invasive species and native predators.
• Conservation efforts should prioritize nest box designs that target specific native species and exclude competitors and predators.
• Careful consideration of local ecological factors is essential for successful nest box implementation in conservation strategies.