Wave the Waders Goodbye
Last week, we were standing in the kitchen, preparing dinner, when the distinctive call of Eastern Curlews flying high overhead reached us. As it was night-time the Kimberley stars were the only thing visible above us but we could hear the Curlews calling to one another as they headed northwards. It’s remarkable to think that you’re witnessing the birds beginning their journey and to know their feet won’t touch the ground for another 5000km.
This is one of the only places in Australia you can witness shorebird migration on this scale. As Broome serves as the last port of call for many of Australia’s migratory species we’re fortunate to not only see the spectacle unfold but have the opportunity to see these waders in their full breeding plumage, a rare treat in the rest of the country.
I bemoan to say that a major part of our role here at the BBO is sitting on the edge of Roebuck Bay, perched behind a scope in the balmy Broome evening with the sun setting over the ocean and watch the shorebirds for a sign of migration. It is taxing, but someone must do it.
Eastern Curlews are usually the first birds to leave. Thanks to over thirty years of research we have a remarkably accurate idea of which species will leave and when. However, nature being nature things don’t always go to plan. The Curlews particularly enjoy being coy and wait until our eyes can no longer strain in the dark and the lens cover has just been replaced on the telescope to begin their display.
When we hear the first Curlews calling overhead, we know that the migration season has begun. Fortunately, most species are not so secretive in their migration and conduct it in broad daylight.
The process of migration has some clear steps that can be watched from the shore and these behavioural clues give us an indication as to whether the birds are considering leaving. Thankfully we have these behavioural signposts as a guide- it can seem a daunting task to pick out 5 birds considering migrating among the hundreds of thousands of birds spread out on the vast mudflats!
Step 1: Politely queuing
As you’re scanning the kilometres of mudflats the first clue for migration is a line made up of a single species. However, unlike the hundreds of thousands of birds around them, they will not be feeding but standing in a neat line, running east to west, seemingly politely awaiting an unspoken instruction. The birds may also be jumping, wing stretching with what seems like nervous energy (behaviour can also be witnessed in humans, at airports).
Step 2: Practice flight
This varies amongst species and groups of birds migrating, however it is common to have birds launch into migration only to come back down to reform their line after a few metres of lift (think: ‘I forgot my keys’, ‘I think I left the iron on’ etc etc.) It can take several attempts before they finally gain enough height and momentum to take off completely,
Step 3: The migration!
Once the birds have lined up, are suitably excitable and had a couple of attempts at take-off it is increasingly likely they will migrate. At this point all telescopes are pointed to the flocks as we aim to catch the number of birds and time of migration. Once the birds gain a certain height it is clear they will migrate. They fly north/ north-west over our heads as they call to one another and form a spectacular V-formation. At this point scopes and even binoculars are redundant as you can now see the birds with the naked eye, stretched out over the sky and hear their wing’s beating furiously. The arc over the Observatory and to the next destination, probably in Asia where they will stop and refuel for the next leg of their journey.
This incredible wildlife experience will continue until mid-May, with anyone welcome to join the BBO staff each evening on Roebuck Bay to help us record the migration. Or come along in a week on Sunday 31st March to our free public event ‘Migration Watch’ we’ll have burgers for sale, telescopes set up and local scientists to chat to, or just bring a picnic sit back and enjoy the show!
See you then,