by Terry Burgess
Probably the best judges of how well the Kakadu Roost went over the migratory season of 2023/24 would be the migratory birds themselves …
… and looking back at the last twelve months, the migratory birds have voted the roost a great success judging from the large numbers and variety of birds arriving at almost every high tide.
The resident birds also had a very positive year, with many chicks hatched both on the beach and in the bush and with the roost and lagoon seeing large numbers of resident waders over the different seasons.
The birds (and the local residents!!) are very lucky to have Michael Strong’s regular bird count throughout the year which goes back decades.
Michael’s history of bird numbers and varieties is an invaluable record that started before the roost and houses were constructed at what was originally the Dux Creek wetland. In the early days, he said that it took a bit of time for the shorebirds to become accustomed to the new roost often preferring to fly overhead to the familiar Dux Creek area.
During the 2023/24 season, we have been fortunate to receive at least one report every fortnight from Michael. These not only include the number of birds at the roost, but some really useful commentary on the birds, their habits and the incredible journeys they make.
As a recap to the year at the roost, here are some snippets from Michael’s comments:
June 2023 - the most exciting thing was that we had 14 Double-banded Plovers hiding in the tidewrack. For at least the last 15 years we have had only threes and fives so this is an unexpected bonus.
July 2023 - Lots of terns, this beautiful morning, - Australian (45), Caspian (23) and Great Crested Terns (14) - the number of Caspians was quite high.
September 2023 - What an exciting morning! Our waders are back again for a new summer. The first vanguard of migratory shorebirds were back on Kakadu Beach after their huge flight from Siberia – Far Eastern Curlew, godwits, knots, a rare solitary Curlew Sandpiper, and Lesser (Siberian) Sand Plovers. It was also very warming to see 11 Red Knot, one of the highest counts in recent years at KBBR. Red knots are diminishing in numbers, partly due to the industrialisation of the Yellow Sea and coasts of Korea and China where they stock up before heading either to Siberia or back to Australia.
October 2023 - There were also 25 Sharp-tailed Sandpipers freshly back from northern Siberia and the first contigent of Red-necked Stints – our smallest wader – also from the Arctic tundras in delicate pale pink and grey brown.
November 2023 - Today was one of those amazing days when KBBR was overflowing with birds. One of the largest totals – 3120 – and certainly the highest number I have recorded this season. One huge flock of over 800 birds arrived en masse. It must be one of the major counts for Far Eastern Curlew (515) – they just kept coming – in big flocks and small groups and even individuals.
December 2023 - Amazing day… one of the highest counts we have had for a long time – just under 4000 birds were counted. There were some major totals too, with more Great Knot (324), Bar-tailed godwits (2900) and Red-capped plovers (32). For the first time in awhile we had 12 Red-necked stints, our tiniest wader, living dangerously on the edge of a flock of 192 big Eastern Curlews.
January 2024 - There were big totals as well – 2817 Bar-tailed godwits; 318 Eastern Curlew, 158 Great Knots and surprisingly, 62 Red-capped Plovers.
March 2024 - The roost was packed with some 3000 birds, predominantly Bar-tailed Godwits (2677) and Great Knot (330), many in full colour ready for the breeding season. Great to see some 103 Far Eastern Curlews, some in their warmer golden brown breeding plumage. Many of the godwits were in their spectacular chestnut breeding plumage, standing out in a usually grey brown flock.
April 2024 - Well, it’s official: our resident shorebirds have left, probably late last week. They will be heading north for the Yellow Sea on their 13,000 km flight, and then separating, with the godwits flying east across the Bering Sea to the Yukon, and the Great Knots turning west into the Siberian tundra.
June 2024 - Winter is also a time when terns flock in larger numbers to the roost. For the first time in a couple of years we had good numbers of Australian Terns (52), with their distinctive black bill and cap. Quite a few Great Crested Terns were on the roost (54), quite distinctive too, with their ragged black crests and yellow beaks.
So the year has turned full circle and thanks to Michael the local community at Kakadu Beach know the story of the roost over the year!!
Michael also has often commented on the migratory birds seen at the roost with leg flags and the importance of having a record of individual birds, their journeys and life span.
In addition to the many Queensland flags spotted - including some on birds flagged well over ten years ago - there were some Interstate flags and also international flags with a couple of Great Knots flagged in Kamchatka, Russia (Black over Yellow flags “LY” and “A2H”) which made an appearance at Kakadu Roost in early 2024.
While sometimes a bit erratic in their sightings, eBirders also contribute to the knowledge base of the roost. While eBirders are generally not that good at counting and frequently underestimate, but there were some high numbers reported with 450 Great Knots in February 2024, 500 Far Eastern Curlews in November 2023 and 3050 Bar-tailed Godwits in October 2023 which were confirmed by Michael’s counts.
Also during the 2023/24 season, eBirders reported, with supporting photos, Terek Sandpipers, Grey-tailed Tattlers and Whimbrels at the roost. As these birds prefer to roost in mangrove trees rather than on a beach so these sightings were generally not around at high tide.
Pacific Golden-Plovers, Sooty Terns and the occasional Blacktailed Godwit, in the mass of the Bar-tailed Godwits, were also reported occasionally by eBirders.
Michael remarked a couple of times that there were fewer Lesser (Siberian) Sand-Plovers seen at the roost through this last season compared with previous years. As they behave differently from the other shorebirds and often are seen leaving the roost in one group flying towards the southeast before the other shorebirds fly off, perhaps there have been some changes in the areas they used to fly to?
Beach-nesting birds were active at the roost as well, with Pied Oystercatchers, Mask Lapwings, Pied Stilts and, of course, the Beach Stone-Curlews seen with chicks around the end of 2023/beginning of 2024. The bush bird chicks also put in an appearance with the Buff-banded Rails and Little Wattlebirds seen with chicks/fledglings.
The roost and lagoon seemed to be in good shape during the whole period while the large numbers of migratory shorebirds were coming into the roost.
Sea water from the Passage was observed to gravitate into the lagoon whenever the tide was roughly above 1.8 metres (tide level at Bongaree). During in the height of the migratory bird season the lagoon was “full”.
The various levels of water in the lagoon over the seasons mean that different birds can be seen using the area - Little Black Cormorants, Pacific Black Ducks & Chestnut Teals prefer deeper water; Little Egrets & Spoonbills prefer shallower water and Pied Stilts prefer a muddy area along the edge of the lagoon to roost and feed.
From talking to some of the Bribie Island-based Council team, who said they have worked on the roost and lagoon for many years, it would appear that there is a single 1,200mm diameter reinforced concrete seawater pipe, with a grid box inlet cover in the Passage, leading to the northern weir box and then a 1,050mm diameter pipeline running under the roost joining the northern weir box to the southern weir box. The top of the inlet grid box is sometimes visible off the beach when the low tide is less than about 0.3 metres.
The water flow is dictated by the level of the water in the Passage, but as the southern weir is further along the pipelines than the northern weir, sandbags are occasionally used in the northern weir box to “tweak” the flow balance between the two weir boxes to even up the incoming flows into the north and south of the lagoon.
The consensus from the Council team was that the weirs work well - with just a bit of leakage through the weir “planks” which is manageable - but they stressed that level of the lagoon will fluctuate with the changes over the year with the high tides and that the lagoon is not lined so there is percolation from the lagoon into the water table.
The grass removal and profiling of the roost towards did not go that well during the year and there was a glitch towards the end of 2023, but overall the shorebirds did not seem to be affected.
There was a view that the godwits would not roost in grassy areas but this was disproved by the birds themselves as many godwits went onto the grassy areas to roost.
The only issue was that when the grass was long the landing areas were restricted especially when the whole beach was put to flight by raptors and 3,000-4,000 birds were trying to land at the same time!
There was also a concern that the area of the roost was too small, but even when there were 4,000 birds on the roost there were still areas of beach available to the north of the roost.
In hindsight, it would probably have been better not to have stopped the Council working on the roost in November to protect the Beach Stone-Curlew chick as it had moved to the shelter of the mangroves prior to the planned date of the work.
The grass growth was compounded a month or so later when there was miscommunication between QWSG and the Council about when to restart the profiling/grass clearing, as the Council was waiting for a message to proceed from QWSG and the clearing was not done until early 2024.
But again, this all probably did not matter as the birds kept flying in and roosting as shown by Michael’s counts.
As noted at the beginning (of what has become quite a lengthy note!!! - apologies for this), the birds and the local community is extremely lucky to have Michael provide the bird count, his commentary and for him share his knowledge with us and anyone who wants to learn more from him when visiting the hides.
This is probably something that QWSG does not fully appreciate when they get Michael’s proforma count list!
Thanks again Michael!!!
Terry Burgess
