Mass tagging of birds on the wing

The two-way radio crackles into life: “Three, two, one …” Bang! Three steel weights are fired from buried canons dragging a tennis court-sized net over a flock of wader birds at the water’s edge. Before the net has settled, 30 people dash down the beach to extricate the birds from the net as quickly as possible.

The priority is the birds’ safety and getting them out of the glaring Kimberley sun and into shade cloth cages erected under temporary shade set up on the beach. The longer it takes for the birds to be shifted, the more risk they are in.

After three weeks of trapping, the group of researchers is well drilled in identifying the species of birds and carefully getting them into cages.

The North West Australian Wader and Tern Expedition is a diverse group of bird lovers, ornithologists and biologists who have travelled as volunteers to Broome Bird Observatory on Roebuck Bay from locations around Europe, Asia and

Australia.

For more than 30 years the group has been coming to Broome to trap, tag and release migratory shorebirds after Roebuck Bay was identified as one of the top locations in the world for wader birds.

Of the 3400 birds captured during the three week trip, more than 350 birds were captured on the final day of the expedition with eight of the region’s 50 wader species represented in the total catch.

At the peak of the non-breeding season, between September and April, the bay is home to more than 120,000 waders.

While most migrate onwards, more than 20,000 mostly immature waders remain in the bay year round.

The birds come to Roebuck Bay for its extensive tidal mud flats, rich in invertebrates, molluscs and worms to fatten up before making the 12,000km journey back to breeding grounds in the Siberian tundra.

During their time in the bay the waders double their body weight in preparation for the 6500km flight to their first stopover in the Yellow Sea, between South Korea and China.

On departing Broome, the waders will fly for five to six days straight at 60kmh to make the journey, burning off excess body weight before piling it all back on again in two to four weeks while feeding in the Yellow Sea before continuing on to Siberia.

The purpose of the expedition’s research is to provide information to governments and environmental groups in an attempt to protect the habitats of wader birds in Australia, Asia and Russia.