Revision of the East Asian-Australasian Flyway Population Estimates for 37 listed Migratory Shorebird Species


Australian Government

Revision of the East Asian-Australasian Flyway (EAAF) Population Estimates for 37 listed Migratory Shorebird Species (Hansen et al. prepared for the Department of the Environment, 2016)

Migratory shorebirds present a particular conservation challenge because their patterns of movement take them across multiple international boundaries, in some cases almost spanning the globe. They utilise different sites in different countries at different times of the year, and conservation of these species therefore requires the management of the suite of sites that are important to them. To identify important habitat in Australia count data and population estimates are required.

Under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), ‘important habitat’ is a key concept for migratory species, as identified in EPBC Act Policy Statement 1.1 Significant Impact Guidelines – Matters of National Environmental Significance 2009. Defining this term for migratory shorebirds in Australia is important to ensure that habitat necessary for the ongoing survival of the 37 species is appropriately managed.

Important habitats in Australia for migratory shorebirds under the EPBC Act include those recognised as nationally or internationally important. The widely accepted and applied approach to identifying internationally important shorebird habitat throughout the world has been through the use of criteria adopted under the Ramsar Convention.

According to this approach, wetland habitat should be considered internationally important if it regularly supports:

  • 1 per cent of the individuals in a population of one species or subspecies of waterbird or
  • a total abundance of at least 20,000 waterbirds.

Nationally important habitat for migratory shorebirds can be defined using a similar approach to these international criteria, i.e. if it regularly supports:

  • 0.1 per cent of the flyway population of a single species of migratory shorebird or
  • 2,000 migratory shorebirds or
  • 15 migratory shorebird species.

To determine population thresholds needed to identify important habitat, the Department previously used population estimates published in the Bamford et al., (2008) report. However, given these published figures are now almost 10 years old, they required updating.

The revised flyway population estimates use newly available data and different analytical approaches to those used in previous population estimate assessments. As a result, the numbers reported cannot be compared with previous estimates to draw conclusions about population trends. Dedicated analyses on data that are comparable over time are the only way to make conclusions about population trends. Any differences between the report’s figures and previous estimates reflect an increase in knowledge and information about migratory shorebirds in the EAAF over the past decade. They do not necessarily represent actual increases or decreases in population size and cannot be used to infer trends in this manner.

Latham’s Snipe (Gallinago hardwickii)*

Latham’s Snipe does not commonly aggregate in large flocks or use the same habitats as many other migratory shorebird species. Consequently, habitat important to Latham’s Snipe is not regularly identified using the process outlined above and different criteria are therefore necessary. Threshold criteria are still considered the best way to identify important sites in the absence of data sufficient for more rigorous methods. Important habitat for Latham’s Snipe is described as areas that have previously been identified as internationally important for the species, or areas that support at least 18 individuals of the species.

A summary of the revised population estimates for 37 migratory shorebirds.

Common Name Flyway population estimate 1% Flyway Population 0.1% Flyway Population
Asian Dowitcher 14,000 140 14
Bar-tailed Godwit 325,000 3250 325
Black-tailed Godwit 160,000 1600 160
Broad-billed Sandpiper 30,000 300 30
Common Greenshank 110,000 1100 110
Common Redshank 75,000-150,000 750 75
Common Sandpiper 190,000 1900 190
Curlew Sandpiper 90,000 900 90
Double-banded Plover 19,000 190 19
Far Eastern Curlew 35,000 350 35
Great Knot 425,000 4250 425
Greater Sand Plover 200,000-300,000 2000 200
Grey Plover 80,000 800 80
Grey-tailed Tattler 70,000 700 70
Latham’s Snipe* 30,000 300 18*
Lesser Sand Plover 180,000-275,000 1800 180
Little Curlew 110,000 1100 110
Little Ringed Plover 150,000 1500 150
Long-toed Stint 230,000 2300 230
Marsh Sandpiper 130,000 1300 130
Oriental Plover 230,000 2300 230
Oriental Pratincole 2,880,000 28,800 2880
Pacific Golden Plover 120,000 1200 120
Pectoral Sandpiper 1,220,000-1,930,000 12,200 1220
Pin-tailed Snipe 170,000 1700 170
Red Knot 110,000 1100 110
Red-necked Phalarope 250,000 2500 250
Red-necked Stint 475,000 4750 475
Ruddy Turnstone 30,000 300 30
Ruff 25,000-100,000 250 25
Sanderling 30,000 300 30
Sharp-tailed Sandpiper 85,000 850 85
Swinhoe’s Snipe 40,000 400 40
Terek Sandpiper 50,000 500 50
Wandering Tattler 10,000-25,000 100 10
Whimbrel 65,000 650 65
Wood Sandpiper 130,000 1300 130

Original link: Revision of the East Asian-Australasian Flyway Population Estimates for 37 listed Migratory Shorebird Species (Australian Government)

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