The Shorebirds Are Getting Ready to Leave. March is the Time to See Them.

Bar-tailed Godwits in flight, Manawatu Estuary, New Zealand. These are the same birds that winter on Australian tidal flats. Image: Wikimedia Commons

Back in our spring edition we wrote about the arrival of migratory shorebirds on Australian shores. Birds that had flown from Arctic and sub-Arctic breeding grounds, some of them non-stop for five or six days, landing on our tidal flats thin and worn and ready to feed. By October most of them had settled in along our coastlines, and through the southern summer they've been doing exactly that, eating, moulting, rebuilding.

Now it's March, and the preparations for the northward journey are well underway.

The Bar-tailed Godwits, Red Knots, Curlew Sandpipers, Red-necked Stints, Ruddy Turnstones, Whimbrel, Eastern Curlew, and others that have been part of our coastal landscape since spring are now in the final stages of getting ready to leave. A lot of them are in the best plumage they'll show all year, breeding colours earned for the northern hemisphere spring, and they are feeding with a focused intensity that is noticeably different to the pace of midsummer. The birding at good tidal sites in March is very good. It's also finite, because once the departure begins in earnest, the numbers thin quickly.

What you'll actually see

The plumage transformation this time of year is one of the things that surprises people who haven't visited a shorebird site in autumn before. Bar-tailed Godwits in breeding dress are warm rufous across the neck and underparts, a long way from the pale brownish-grey of a bird that arrived in September. Red Knots in full breeding plumage are brick-red from face to belly. Curlew Sandpipers in breeding colours are deep chestnut across the body. These are not subtle changes. Side by side with the same species in non-breeding plumage, they look like different birds.

The species mix is also shifting. Some of the less common species that were present through the summer are still around in small numbers, and this is a time when working through a flock carefully can turn up something unexpected. It's worth taking your time rather than just ticking the obvious species and moving on.

Where to go

Shorebird site quality comes down to the extent and quality of intertidal mudflat, and disturbance levels. The well-known sites are well-known because they've produced birds consistently across many years of observation.

On the east coast, the Hunter Estuary and Kooragang Island in NSW are among the most reliable sites in the country. Corner Inlet in Victoria holds good concentrations of godwit and knot through March. The Coorong in South Australia covers a vast area of tidal habitat with consistent diversity. In Queensland, the Cairns Esplanade foreshore puts a wide range of species at close range on most mornings, and it's accessible even for visitors without a car.

In Western Australia, Roebuck Bay at Broome is the benchmark. Large tidal range, extensive mudflat, and species diversity among the best in Australia. Eighty Mile Beach to the south is larger and less visited. If you can get to either of those in March, it's worth prioritising over almost anything else.

Working with the tide

A shorebird site at low tide can look nearly empty. Birds spread out across the exposed mudflat to feed and can be very distant, sometimes several hundred metres from shore, visible only as dots. At high tide, the water covers the feeding areas and pushes birds into tight roosts on sandbars, elevated margins, and patches of higher ground, often at much closer range. These two states are different experiences, and that difference matters.

The approach that tends to work well is arriving two hours before high tide, watching the feeding flocks contract towards shore as the water rises, then settling in to observe the roost at high water when birds are packed together and accessible. The first feeding session after the tide begins to drop is also productive.

First light and a rising tide together is about as good as shorebird birding gets.

How to work a roost

A high-tide roost looks uniform at first glance. Hundreds or thousands of birds packed together, mostly sleeping or preening, appearing similar in size and colour on a casual scan. The unusual species in that flock are just sitting in there with the common birds, and the only way to find them is to go through the flock methodically, checking each bird.

The things worth checking are body size relative to immediately adjacent birds, bill length and shape, and leg colour. A Ruff among Red-necked Stints is considerably larger than everything around it, but you won't register that unless you're comparing it to its neighbours. Lesser and Greater Sand Plovers require close structural attention. A scope is what makes this kind of work possible at any real distance, because the identifying features of difficult shorebird species live at a resolution that binoculars at a hundred and fifty metres don't deliver.

It's worth submitting your counts

The East Asian-Australasian Flyway, the migration system connecting Australian coastlines to Arctic breeding grounds through south-east Asia, is under significant pressure from ongoing tidal flat reclamation along the Yellow Sea coast. Critical staging sites that shorebirds depend on for both legs of the migration have been lost or degraded at a scale that has driven clear population declines across several species over the past two decades.

Australian observers contribute to the international monitoring that documents these trends and supports habitat protection arguments in the countries where the damage is occurring. If you read a leg flag or wing tag at a shorebird site, report it to the Australasian Wader Studies Group at awsg.org.au. Your counts and sighting records submitted through eBird feed into this work as well, and they're worth doing carefully.