Report on Australian Shorebird Population Counts Winter 2009 and Summer 2009-10

Report on Australian shorebird population counts Winter 2009 and Summer 2009-10

Sjouke Scholten1, Liam Costello1, David A. Milton2 and Golo Maurer1*

1Birds Australia, Australasian Waders Study Group, Suite 2-05, 60 Leicester St, Carlton, Victoria, 3053, Australia

2Queensland Wader Study Group, 336 Prout Rd., Burbank, Queensland, 4156, Australia.

* Author for correspondence

Abstract

Shorebird count data have been collected throughout Australia for almost thirty years. Here we present data collected by more than 1300 registered volunteers in Birds Australia’s Shorebirds 2020 programme for the winter 2009 (89 Shorebird Areas 30785 birds of 37 species) and the summer 2009/2010 (120 Shorebird Areas 587487 birds of 46 species). This report has been compiled with a different methodology from that used for many previous reports. The data reported are those collected closest to the 30th of June 2009 (winter count) and the 15th of January (summer count) for each shorebird area. Like previous reports, however, it is not suitable for detailed scrutiny of regional or local population trends. For such analyses the complete data held in the Shorebirds 2020 database must be used and, where possible, the original observers should be consulted. While considerable progress has been made towards comprehensive monitoring of shorebirds in Australia gaps still remain in the northern part of the country.

Introduction

At its inception, Birds Australia’s Shorebirds 2020 monitoring programme aimed to reinvigorate shorebird population monitoring in Australia (Oldland et al. 2009). The explicit aim was to generate quality monitoring data with a sufficient temporal and spatial coverage to allow for reliable assessment of population trends in migratory shorebirds Australia-wide and in important shorebird habitats. The data from counts made in the 2009-2010 season indicate that a sustained increase in shorebird monitoring has occurred in Australia. If this effort can be sustained, sufficient data should be available to detect rapid, large scale population trends for approximately half of Australia’s migratory shorebirds species within the next 3-5 years with appropriate statistical power (Clemens et al. 2009).

Here we present the data of the winter counts 2009 (89 Shorebird Areas) and the summer counts 2009/2010 (120 Shorebird Areas). However, no comparison with previous Australian shorebird population reports has been undertaken. We also stress that for detailed analyses of regional or local population trends, only the original data rather than summary data reported here or in previous reports should be used (e.g. Olivera and Clemens 2009). The reasons for this are that the number of count areas visited for each shorebird area count is likely to differ across reports and important details such as a difference in the identity and number of counters, disturbance during the counts or other specific comments will be missed.

Importantly, in this summary the methodology of reporting shorebird counts has changed from the varying methodologies used in previous reports. The details are presented in the methods and the implications of these changes are considered in the discussion. In brief, we do not use the absolute maximum counted for each species in each Count Area in a season to calculate the Shorebird Area totals as in the last report (Olivera and Clemens 2009). Instead, we use the number of birds counted at a time closest to a central date to calculate these totals. This approach reflects the recommendation for counts to be conducted as closely as possible to a unified summer and winter count date which is part of the Shorebirds 2020 approach. It also is a more conservative approach than previously used as it reduces the opportunity for double counting. Finally it allows for easy repeatability of the analysis both with the year but also for past and future reporting periods.

Methods

Data collection

More than 300 volunteers have submitted data collected by a conservatively estimated 1300 volunteers to Birds Australia’s Shorebirds 2020 shorebird monitoring programme in spatially defined ecological units (Shorebird Areas) divided up into practical units (Count Areas) across Australia. Observers followed a consistent approach and used maps and guidelines provided by Shorebirds 2020. These methods were promoted online and through local training workshops. Counts were undertaken at high tide roosts by individuals or groups of observers with binoculars and telescopes. Local count coordinators ensured that within Shorebird Areas all Count Areas were visited simultaneously and the counts were corrected for multiple observations of the same birds. Most data were submitted to Shorebirds 2020 through its online database. However, Shorebirds 2020 paper forms and traditionally used paper forms were also submitted. Detailed maps of Shorebird Areas and Count Areas can be found on

Data preparation

Data vetting occurred in two stages; first by the regional coordinator, when the data were transferred to the online data base or count form and then by the Shorebirds 2020 team at Birds Australia’s National office (BANO) with the exception of the data for Queensland, which were vetted by the Queensland Wader Study Group.

To produce the report, we queried the online Shorebirds 2020 database for data collected for each count area closest to a central date for each season. This query was used to calculate the total number of individuals per species for each shorebird area. These central dates were the 30th of June (Winter 2009) 15th of January (Summer 2009/2010). Counts considered for the winter survey were those conducted within 36 days of the central date. If no counts were made in this period for the shorebird area in question, no winter count data were reported. Similarly, for the summer counts data were included for a period within 75 days of the central date, i.e. between the 2nd of November 2009 and the 31st of March 2010. Again, if no counts were made during that period, no summer count data were reported. The summary data for Queensland were prepared independently by DM, Queensland Wader Study Group (QWSG). These data were taken from the sum of the July and January counts at high tide roosts within specific shorebird areas. These data do not represent the total counts from that shorebird area, but only from those count areas that have been surveyed since QWSG began supplying data to the Australasian Wader Studies Group in the early 1990s.

We also determined the number of shorebird areas visited by state and the number of count areas visited by state and by shorebird area for each season based on the data submitted to BANO.

Results

Here we present data of the winter counts 2009 and the summer counts 2009/2010 in overview (Table 1 and Table 2 respectively). Observations for each Shorebird Area are reported for Winter 2009 and Summer 2009-2010 in Table 3 and Table 4 respectively. In the winter counts, 89 Shorebird Areas were visited across Australia and a total of 30785 shorebirds counted. In the summer counts 120 shorebird areas were covered with a total of 587487 birds counted.

The highest total count in winter was of Bar-tailed Godwit (5630), Red-necked Stint (4649) and Double-banded Plover (4386). These species were also the most frequently encountered migrants with observations in 25, 36 and 35 Shorebird Areas. Amongst residents, the Red-capped Plover (3476), Black-winged Stilt (3220) and Pied Oystercatcher (2910) were the most frequent species. Red-capped Plover and Pied Oystercatcher were also the species found most frequently in 44 and 43 shorebird Areas respectively, while Black winged Stilts were found in 29 Shorebird areas. Remarkably, only 275 Banded Stilts were observed in five shorebird areas.

The highest total numbers in summer were counted for Great Knot (158855), Red-necked Stint (108811) and Bar-tailed Godwit (102950). The migrants encountered in most Shorebird Areas were, however, Red-necked Stint (82), Common Greenshank (63) and Sharp-tailed Sandpiper (61). Bar-tailed Godwit only found in 57 Shorebird Areas. The most frequently encountered resident species were Red-capped Plover (16851), Black-winged Stilt (7590) and Pied Oystercatcher (7352). Red-capped Plover was also the resident found in most Shorebird Areas (86) followed by Masked Lapwing (81) and Pied Oystercatcher (74), while Black winged Stilts were found in 45 Shorebird areas.

The numbers of Shorebird Areas visited in each state during the winter period (excluding QLD), and summer counts are shown in Tables 1 and 2. On average, approximately between one third and one half of all registered Shorebird Areas were visited during winter and summer counts, respectively. Table 3 and Table 4 present counts for all shorebird Areas visited in winter 2009 and summer 2009-2010 respectively. The counts are presented per state and Shorebird Areas and are listed in alphabetical order.

Discussion

This report presents an overview of shorebirds in Australia during the Austral winter 2009 and the Austral summer 2009-2010. It differs from reports in previous years in that a new reporting methodology has been established. In this report we did not attempt to compile the absolute maximum for each species recorded in each Count Area or Shorebird Area during a winter or summer period. Instead, we present the data for each Count Area that were collected closest to a central date: 30th of June for the winter counts and 15th of January for the summer counts. We consider this approach more conservative and a better standardisation than aiming for the maximum shorebird number reported for each period. In areas where only a single count is made each season, the results obtained with either method would be identical. For areas with more frequent counts, however, the data presented here may differ from those presented in earlier reports. Regardless of the approach taken, it is important to note that data presented in this and previous Australian shorebird population reports are not suitable for complex analyses or for Australia wide or within Shorebird Area comparisons. People who wish to scrutinize regional or local population trends should, therefore, always refer to the full dataset held in the Shorebirds 2020 database and contact the original observers for their analyses rather than of the summaries provided in this report.

The Shorebirds 2020 monitoring does not aim to provide a full inventory of shorebirds in Australia. Rather, it compiles a subsample of shorebird numbers to allow the project to analyse trends of overall shorebird populations. Nonetheless, it is important to note that for some of the most common migratory shorebird species such as Great Knot, Bar-tailed Godwit and Red-necked Stint counted numbers amount to approximately half the population estimate for the species in Australia (Geering et al. 2007).

For resident shorebird species, the picture is more mixed. While only about 15% of the estimated total population of Red-capped Plovers was counted during the surveys, about 70 % of the Pied Oystercatcher population was recorded during Shorebirds 2020 monitoring (Geering et al. 2007). This is likely a reflection of the different detectability and specific habitat requirements of different shorebird species.

In this report we also present data on coverage of Shorebird Areas by state, which was rarely available in previous reports. These data will help to give an estimate of the representativeness of the data compiled for preliminary analyses. Nonetheless, a detailed analysis of trends will still require using the original data.

The data on Shorebirds Areas visited vs. Shorebird Areas identified can also be used to guide future activities for the Shorebirds 2020 program. For instance, the data show, perhaps unsurprisingly, that states with significant shorebird habitat in northern and remote regions have rather incomplete coverage. Coverage in these areas suffers from both the lack of observers locally and the distance from major urban centres. Many of theses areas provide, however, important shorebird habitat and are likely to hold considerable numbers of birds. For reliable analysis of Australia-wide trends in counts, additional surveys in these areas are essential. This highlights the need for a concerted effort for surveys in northern and remote Australia that will require considerable additional funds as some areas may only be accessible by air.

The percentage of species’ populations counted in Shorebirds 2020 counts especially for key migratory shorebird species provides some confidence for population trends deduced from the monitoring data. However, given the incomplete spatial coverage, especially in northern Australia, much uncertainty remains regarding absolute numbers of population changes. This uncertainty regarding shorebird population data for the East-Asian Australasian flyway is similar to that found in other flyways (Colwell 2010). It can only be addressed through increased spatial coverage of the survey effort. The huge inter-specific variation in percentage of the population counted during the winter and summer surveys makes population trends more reliable for some species such as the Pied Oystercatcher or the Sanderling. These species have about 70% of their Australian population counted. Whereas,other species such as. the Little Curlew have only 2% of the estimated Australian population being monitored. This variation highlights some of the limitations of the current Shorebirds 2020 program in terms of its geographical and habitat coverage.

Acknowledgements

We would like to thank all the counters and coordinators for their incredible effort in collecting the data presented in this overview. The list below identifies the persons that have provided data to Shorebirds 2020. This may be either in paper or electronic form. However, we would also like to those volunteers who joined surveys but may not be listed here as their data have been submitted by the coordinator.

We would also like to thank the Commonwealth Department for Sustainability, Environment, Water, Population and Communities for funding support of this project and its publication and the federal government Caring for Our Country Initiative for funding to help establish the Shorebirds 2020 programme.

Coordinators

George & Teresa Baker, Chris Baxter, Rod Bird, John & Judy Blyth, Anne Bondin, Hazel Britton, Nigel & Mavis Burgess, Denis Charlesworth, Greg Clancy, Maureen Christie, Rob Clemens, Jane Cooper, Ralph Cooper, Trevor Cowie, Phil Craven, Mike Crowley, Linda Cross, Peter Dann, Peter Duckworth,Len & Chris Ezzy, Rob Farnes, Winston Filewood, Shirley Fish, Les George, Alan Gillanders, Margaret Hamon, Judy Harrington, Chris Hassell, Jane Hayes, Colin Heap, Janice Hosking, Steve Johnson, Julie Keys, John Lowry, Hans Lutter, Sue Mather, Clive Minton, John Newman, Gavin O’Brien, Jo Oldland, Jan Olley, Kimberly Onton, Rosemary Payet, Robyn Pickering, Ken Read, Danny Rogers, Dick Rule, Mary Satchell, Roger Standen, Bob Semmens, Paul Shelly, Bryce Taylor, Margie Tiller, Kent Treloar, Hazel Watson, Toni Webster, Jim & Anthea Whitelaw, Bill & Evelyn Williams, Eric Woehler, Kevin Wood, Liz Znidersic.

Groups

Bellarine Peninsula Shorebird Observer, Birds Australia WA (BAWA), NSW Wader Data Base, Queensland Wader Study Group (QWSG), SESA Shorebirds

New South Wales

Chris Brandis,Frances Bray, Jeff Campbell, Greg Clancy, Simon Clayton, , Martin Cocker, Rod Corinaldi, Ricki Coughlan, Phil Craven, Mike Crowley,Joan Dawes, Rob Farnes, Winston Filewood, Margaret Hamon, John Harding, Judy Harrington, Janice Hosking, Nigel Jackett, Russell Jago, Julie Keys, Cilla Kinross, Ann Lindsey, Hans Lutter, Gordon McCarthy, Alan Morris, Jo Oldland, Jan Olley, Joy Pegler, Joan Rosenthal, Peter Roberts, Bob Rusk, Paul Shelly, Alan Stuart, Bryce Taylor, Pete Ward, Hazel Watson, Rex Worrell, Mark Young.

Northern Territory

Ian Hance, Colin Heap, Arthur & Sheryl Keates, Peter Kyne Gavin O’Brien .

Queensland

George & Teresa Baker, Chris Barnes, Lainie Berry, Dominic Chaplin, Rob Clemens, Rob Collyer, Len & Chris Ezzy, Alan Gillanders, Ian Leach, Jan Lewis, John Lowry, Jun Matsui, Rosemary Payet, Ivor Preston, Mary Satchell, John Stewart, Robert Wroth.

South Australia

Sue Abbotts, Heather Adamson, Jim Allen, Rod Attwood, George & Teresa Baker, Mike Barth, Chris Baxter, Cath Bell, Mel Berris, Steve Berris, John & Judy Blyth, Chris Brandis, Hazel Britton, Nigel & Mavis Burgess, Jeff Campbell, Derek Carter

, Maureen Christie, Rob Clemens, Jane Cooper, Ralph Cooper, Trevor Stephen James Cowie, Graham Andrew Crooks, Peter Dann, Peter Day, Rob Farnes, Anthony Frederick France, Toby Galligan, Les George, Peter Gower, Dorothy & Phil Green, Phill Du Guesclin, Travis Hague, Margaret Hamon, Judy Harrington, Jean Haywood, Colin Heap, Anne Houghton, Bea Hurrell, Teresa Jack, Alan Jamieson, Barbara Jones, Richard Jordan, Gregory Ker, Michele Jane Lane, Sue Mather, David McCarthy, Ken Monson, Euan Moore, Alan Morris, Kay Muggleton, Vicki Natt, Gavin O’Brien, Jo Oldland, Jan Olley, Kimberly Onton, Robyn Pickering, Chris Purnell, Ken Read, Jane Renwick, Robert & Krystyna Rowland, Bob Rusk, Tony Russell, David Secomb, John Spiers, Iain Stewart, Rod Sutherland, Rod Tetlow, Margie Tiller, Kent Treloar, Brian Walker, Steve Walsh, Jim & Anthea Whitelaw, Ernie Wild, Bill & Evelyn Williams, Sue Winwood, Stella Wynne, Lynda Yates, Liz Znidersic.