What if we told you that eating oysters could help migratory shorebirds in Moreton Bay?

Before we talk about shellfish, let’s look at our beautiful, winged friends for a moment.

The life of migratory shorebirds and their fine-line

Every year, 30,000 migratory shorebirds make an impressive journey of tens of thousands of kilometres over a few days, as they travel to and from the northern hemisphere (where they breed) and our shores (where they feed).
The sheer number of birds is a reason for Moreton Bay’s listing as a Ramsar site, and they come for the food!
Migratory shorebirds are here to feed and gain enough weight to make their way back home and breed successfully. Eating and gaining weight sounds like an easy thing to do – but it’s not so easy for them.
Along with plenty of good food, peaceful resting places (roosts) are vital for migratory shorebirds to conserve precious energy whilst their feeding grounds are underwater; even seemingly small changes to their feeding regime can impact successful migration.
When high-tide roosts near feeding areas are unavailable or become compromised by disturbance and/or development, migratory shorebirds expend crucial energy reserves travelling to other roosts, energy that they would otherwise be able to use for their long migration.
This means that some might not have the energy to make it to the next stop on their migration journey.

Why the project

Unfortunately, good conditions for migratory shorebirds to prepare for their long journey are diminishing.
Loss of multiple roosting and foraging sites over time in Moreton Bay and elsewhere has led to dramatic declines in global populations of migratory shorebirds and led to some, such as the iconic far eastern curlew, being listed as critically endangered.
Human activities are primarily responsible for habitat loss and when combined with increasing disturbance through recreational and other use of our foreshores and coastal environments, intervening management actions are imperative for shorebird survival.

Shellfish to the rescue

To help our beautiful birds in their fight against threats, in consultation with shorebird experts, BirdLife Australia, Traditional Owners, and governments, we are trialling floating roosts in three locations: western Minjerribah (North Stradbroke Island), Bungumba (Mud Island), and Pumicestone Passage. These sites were selected due to low use and disturbance by people, proximity to migratory shorebird roosting and feeding areas, minimal cultural or environmental impact, and limited impact on Moreton Bay Marine Park users.

This is where shellfish come to the rescue! Our artificial floating roosts are made of lines of floating bags filled with locally sourced, oyster shells. The shells of oysters and other molluscs are collected from seafood businesses and restaurants across Brisbane, and sanitized by project partner OzFish, before their use in the floating roosts and other projects such as constructed oyster reefs.

The floating roosts rise and fall with the tide, limiting impact to marine plants and wildlife and, being partially submerged, they provide a cooler surface preferred by roosting migratory shorebirds and allow for colonization by marine invertebrates, some of which may become prey for shorebirds.

“Our short-term trial of floating roosts in less disturbed places near quality feeding areas (such as intertidal mudflats), aims to give shorebirds what they need and guide future conservation and management,” says Liz Gould, Healthy Land & Water’s Senior Principal Scientist.

"We are monitoring each trial with cameras and regular visits to see how birds respond to the newly available, floating high-tide roosts, and how the structures are holding up."

Some of the benefits

Previous trials by BirdLife Australia have shown that these floating roosts can be very attractive to migratory shorebirds and we hope to have similar success in the coming months.

In addition, the floating roosts have proven little negative environmental impact while having a positive impact on shorebird conservation and habitat restoration.

The use of screw anchors and UV-stabilised commercial aquaculture equipment means the floating oyster bags meet best practice oyster farming cultivation methods and allow natural underwater processes to continue while not impacting the movement of fish and other marine life.

We couldn’t have done it without…

Thanks to the Kabi Kabi and Quandamooka Peoples for their care of Country and support of the project, BirdLife Australia for sharing the floating roost design, QWSG for shorebird advice, QYAC, OzFish, and BIEPA for assistance with installation, and the Queensland Government for permits and approvals. This project is funded by the Australian Government.