The Victorian Wader Study Group (VWSG) was formally constituted in 1978, however fieldwork actually began in 1975. The VWSG's primary objective is to conduct a long-term comprehensive study of waders and terns throughout Victoria. The VWSG is a non-profit organisation and is made up of around 140 volunteers.
The VWSG monitors both migrant and resident species. Research objectives includes:
- Population monitoring (by counting and catching)
- Determination of migration routes, stopover locations and destinations
- Biometrics of species and subpopulations
- Weight changes associated with migration
- Primary moult duration and mode
- Survival rates
- Reproductive rates
- Behavioural differences between adult and immature birds
- Determination of age when species first breed
Results from the VWSG activities are reported annually in their Bulletin. All bulletins can be downloaded from the publications page.
What are waders?
Waders, also known as shorebirds, include all those birds that use the water's edge for feeding. This generally involves utilising the mudflats that are exposed as water recedes (either by tide in marine environments or evaporation in fresh water bodies). These habitats are under significant threat around the state of Victoria, and the world.
Waders range from the tiny Red-necked Stint (weighing less than 30gms) up to the large Eastern Curlew (a robust 600gm building to well over a kilogram when fuelled up for migration flight).
Most of the migratory waders that spend part of their life in Australia breed in the arctic and travel here to avoid the northern winter. This requires access to refuelling grounds along the way. A critical part of the VWSG's work has been to contribute valuable data that has led to a greater understanding of where these habitats are and srengthened arguments for saving them.
Some examples of waders are shown in the picture gallery .
The VWSG mostly uses a technique called cannon-netting to catch waders for various scientific research projects (approved by the Australian Bird and Bat Banding Scheme - ABBBS). It also uses a technique called mist-netting for species such as Latham's Snipe.
What is cannon-netting?
Cannon-netting is a technique that has been used for over 35 years to catch waders (and other birds) as part of the many research programs conducted across many countries.
As the name implies, this is a process that uses small cannons that shoot projectiles, attached to a net, out over birds standing on the ground in front of the net.
Some of the steps in how it works include:
- Doing pre-catch reconnoitres to likely roosting sites to see where it may be best to set up the nets
- Carrying the materials to the site and setting the net (pegging the back line down, burying the cannons, furling the net to ensure it opens smoothly, camouflaging the net to make it blend in to the site and laying cables back to the hide for firing)
- Posting people to points where they can see the catching area and ensure the safety of the birds
- Twinkling the birds into the catching zone
- Firing the cannons
- Covering the net with shade cloth to keep the birds calm
- When the net has trapped the birds, trained extractors take the birds from the net and they are carried to holding cages (frames covered in dark shade cloth to keep the birds calm) before being processed.
- After processing, the birds are released to join their flocks.
There are strict protocols in place to ensure the safety of the birds remains paramount. An induction manual for new volunteers getting involved with catching has been prepared by the VWSG. It can be downloaded here.
What is mist-netting?
Mist-netting is a long-standing research technique for catching many bird and bat species.
It involves tying up a fine net between poles that can be set near a flight path of the birds. The net has loose flaps in it that catch the birds after they fly into the net and then fall into the flaps.
The net is so fine it is difficult for the birds to see. Waders have such good vision they won't get caught in a mist net in the daylight (unlike many of the bushbirds), so waders get caught at night as they move between feeding and roosting sites.
Birds are only removed from the nets by experienced and licensed banders.
Catching Totals - Cannon and Mist Netting
A total of 38 species have been caught and banded by the VWSG from 1975-2012, with 237,202 total individual birds, including 46,791 retrapped birds. Download details of annual banding totals from the latest Bulletin that can be found here.
What is Banding?
Small metal rings that are labelled with a unique number are placed on the leg of the bird to enable any recovery or recapture of the bird to be traced back to the time it was initially caught. From this, data on movements, age and survival rates can be determined.
What is a Leg Flag?
A flag is a coloured plastic leg band with a small extension that can be seen through binoculars or scopes at a distance. Over the past 14 years, flag development has continually advanced, with the most recent changes being new alphanumeric labels on the flags that reduce the need for multiple leg bands when trying to identify individual birds.
What is Processing?
A bird is processed when its biometrics, or body measurements are taken. This happens when the birds are caught for banding, although depending on the purpose of the study and the time available to handle the birds, not all measurements are taken for every bird. Various measurements taken include:
- Bill length
- Head and bill length
- Wing length
- Stage of moult
The bird has a unique identifying metal band placed on its leg (for identifying on recovery) and usually a leg flag as well for identification in flocks.
What is a Recovery?
A recovery is when another bander recaptures a banded bird or when a banded bird is found dead, locally or at another location.
What generally happens in these cases is that the metal band number is reported to the Australian Bird and Bat Banding Scheme in Canberra, or to the bander.
What is Twinkling?
'Twinkling' refers to the process of gently encouraging birds to move into the catching area in front of the net.
This can take many forms, from:
- using a four-wheel drive vehicle as is the case on the vast 80 Mile Beach in north-west Australia, to
- having people walk slowly along a beach, to
- having people (with protective waders of course), carefully move across the ponds at the Werribee Sewage Treatment Plant, or
- having people crawl along on their bellies - commando style - or to
- people simply making themselves visible by standing up from a hidden position - all used in different situations to encourage that last short movement by the target birds.
Leg-flagged Waders from Victoria
An orange plastic leg-flag has been placed on the right tibia of most migrant and some resident waders banded in Victoria since 1990. This has led to a significant increase in the rate at which data has been generated on migration routes and key stopover regions in the flyway. Lists of sightings of orange flagged birds away from the banding areas, both in Australia and overseas, what species have orange (and the South Australian yellow/orange) leg flags and in what years they were applied have been published in past VWSG Bulletins (and in the AWSG bulletin, The Stilt).
If you see any waders, or terns, with any coloured flags attached to their legs, please note as much as you can about the placement and colour of the flags and or bands.
Tern studies have been an integral part of the VWSG's activities since the group's early days, even though the group's name does not include them. The official approved Banding Project does however mention waders and tern equally. Some terns have also been orange leg-flagged, and even Little Terns have been individually leg-flagged with various colour combinations involving three flags. Crested Tern chicks on Mud Island have had ABBBS metal bands powdercoated different colours for different years. For more information on the VWSG's involvement with Crested Terns banded on Mud Island click here.
Pied Oystercatcher studies
The Pied Oystercatcher population of Australia is only about 10,000 individuals with 1,500 in Victoria. The VWSG have been conducting a study of Pied Oystercatchers in Victoria since early 1979. Oystercatchers have been banded at various locations in Port Phillip Bay, Western Port and the Corner Inlet complex.
The banding system initially involved individual birds having two colour bands placed above a metal ABBBS band on one leg, and three colour bands placed on the other leg as a unique combination, allowing individual birds to be identified in the field.
However, more recently they have an engraved leg flag applied.
If you sight a banded Oystercatcher please contact David Trudgen.