Victorian Wader Study Group Activities





Lots more news deriving from Victorian Wader Study Group activities! This report covers recent sightings of flagged birds seen during their northward migration back to their Northern Hemisphere breeding grounds, some exciting records from the Alaskan breeding areas, and the beginning of the southward migration back through the Yellow Sea. It also summarises the final results of our ≥% juvenile≤ monitoring in catches during the 08/09 summer, which give a measure of the breeding outcomes for a range of species in the 2008 Arctic summer. Finally, news is included of recent VWSG Fieldwork banding activities.



FLAG SIGHTINGS



An incredible 423 sightings of VWSG-flagged birds were reported during the April/July period. The majority of these relate to birds on migration through Asia, mainly during northward migration in April and May.



There was a massive total of 321 flag-sightings in mainland China and a further 27 in Hong Kong. An amazing 141 of these records relate to Red Knot flagged in Victoria and seen in the north-west sector of the Yellow Sea in May near Bohai, China. These sightings mostly derive from an intensive period of fieldwork in China carried out by two Australian wader experts who live in Broome (Chris Hassell and Adrian Boyle). There have been some reports of flagged Red Knots in that same region in previous years but this yearπs fieldwork confirmed that it is the major staging area for Red Knot in Asia during northward migration, with nearly 50,000 Red Knot being counted.



Red-necked Stint also featured strongly with 107 records in mainland China and a further 20 sightings in Hong Kong. The former were mainly also in the north-western section of the Yellow Sea. Some were on northward migration but a greater proportion were southward migrating adults in late July.



Bar-tailed Godwit sightings provided an interesting pattern, further confirming that the birds from south-east Australia have a rather more easterly path through the Yellow Sea on northward migration than Bar-tailed Godwits from north-western Australia. There were 12 south-east Australian  birds seen on the Chinese parts of the Yellow Sea but 27 on the more easterly Korean shores, and 3 in Japan.



But the most exciting flag sightings of all during the period were 3 Bar-tailed Godwits seen on their breeding grounds in Alaska in June and early July. All three were on the North Slope at approximately 70∫ North. One was a long way to the east at Longitude 149∫ West. This is 13,000 km. from the Victorian flagging locations.



Thanks are due to Heather Gibbs, who manages the leg flag database and who extracted for me the information on which this report is based.



We await further exciting reports of our flagged birds on southward migration!



2008 BREEDING SUCCESS



For the last 30 years the VWSG has attempted to obtain a measure of the annual breeding success of a range of wader species which spend the non-breeding season in south-eastern Australia. This is done by measuring the proportion of juvenile/first-year birds in cannon-net catches in the period late November to late March, when wader populations are relatively stable.



Sadly, the Northern Hemisphere 2008 breeding season was the worst ever recorded during this long-term study. Only Bar-tailed Godwits, which breed in Alaska, had a better than average outcome. All the Siberian Arctic-breeding waders had a poor breeding year. Red-necked Stint and Curlew Sandpiper productivity were only slightly below the long-term average but Ruddy Turnstone, Sanderling and Sharp-tailed Sandpiper experienced an almost complete breeding failure. It was also probably a poor year for Red Knot breeding success though we were not able to catch a satisfactory sample to show this. But the Red Knot summer population throughout Victoria was very low and no Red Knot were present at locations frequently visited by juveniles in good breeding years.



It is now five years since Red-necked Stint had an above average level of breeding success. Count data shows that their population has declined significantly from the extremely high levels of the late 1990s/early 2000s, when a series of exceptionally good breeding seasons occurred.



Curlew Sandpiper continued their roller coaster ride with good and bad years alternating. The relatively poor outcome this year followed an exceptionally productive 2007 breeding season. A sustained period of above average breeding success is badly needed to reverse, as opposed to halt, the long downward trend in numbers of this species.



Sharp-tailed Sandpipers had their worst breeding outcome for 20 years. The long run of above average breeding success which this species experienced between 2002 and 2007 seems to have come to an abrupt end with only 3.6% juveniles in the 08/09 summer populations. Overall numbers of Sharpies are, however, still at much higher levels than they were between the late 1980s and early 2000s, as a result of the extended breeding bonanza period.



Sanderling quite regularly seem to have extremely poor breeding outcomes, but these are partly offset by occasional exceptionally good breeding success years. The 2.9% juveniles in 2008/09 is the sixth time in the 18 years of data collection that the figure has been below 3%. Ruddy Turnstone fared even worse with only 0.7% juveniles - just three juveniles in 396 birds caught in 12 catches. This is the lowest ever figure for Ruddy Turnstone and is the second really bad breeding outcome in the last three years. Turnstones populations are noticeably reduced in Victoria, the south-east of South Australia and in King Island.



The sole good breeding outcome for SEA wader populations in 2008 was Bar-tailed Godwit. The figure was particularly good when measured against the long-term median. Four of the last five years have now had an above-average percentage of juveniles. One result is that the over-wintering population in 2009 at the main habitat in Victoria (Corner Inlet) was high and has only been exceeded in three of the last 28 years. Catch data has shown that over-wintering birds are predominantly one- and two-year old birds with just a small number of three-year-olds.



Clearly there was a most unfavourable combination of conditions experienced across a wide range of the Siberian Arctic during the June/July breeding season in 2008. The key factors which can affect breeding success include the date of snowmelt, average June and (especially) July temperatures, late snowfalls during the early July hatching period, and predator levels (Arctic foxes, Snowy Owls, Arctic Skuas). Let us hope that during the current 2009 breeding season the outcomes for our waders are much more favourable.



RECENT FIELDWORK



The VWSG caught 2,422 waders in the first half of 2009. This total is smaller than usual, because of a lack of large Red-necked Stint catches. But it contained a very good variety of species in worthwhile numbers, topped by 459 Ruddy Turnstone, 386 Bar-tailed Godwit, 172 Sanderling and 136 Red Knot.



It was particularly pleasing to get a superb catch of 176 Bar-tailed Godwits and 135 Red Knot (with 7 Great Knot) on the east end of Clonmel Island in Corner Inlet in late June. This was our largest ever winter catch of Bar-tailed Godwits and our fourth largest for Red Knot. All the Bar-tailed Godwits were given engraved orange flags so these should lead to some excellent sightings of individually identifiable birds in the future. All except one of the birds handled in this catch were immatures, with 80% being juvenile/first year. The exception was a five-year-old Bar-tailed Godwit. It is not clear why this bird had not gone north to breed (normally at age 3 or 4 for the first time.)



We have not done quite so well on our long-term Pied and Sooty Oystercatcher project this winter. Up to the end of July we have only caught 95 Pied Oystercatchers (against an annual target of 150) and 63 Sooty Oystercatchers (against a revised minimum target of 75). Consequently some additional fieldwork has now been scheduled for August.



Following that the VWSG Annual General Meeting will be held on Saturday September 12th. This is a highlight of each year, giving the opportunity for 60 or more VWSG members to get together for a full day for net mending, the formal annual review meeting, a series of illustrated talks, and copious good food!! The main fieldwork season then resumes in October.

Clive Minton