Welcome to Module 3
SHORT-TAILED SHEARWATERS
Welcome to the Short-tailed Shearwater module of Cradle Coast Natural Resource Management’s online learning package. In this module, you will learn about Short-tailed Shearwaters
- Their habitat and ecology
- How and why Short-tailed Shearwaters are under threat
- What you can do to help reduce the threats to Short-tailed Shearwaters
This module will take you about 1 hour to complete.
How to move through this online course
As you are guided through this module, you will learn about Short-tailed Shearwaters through reading text and watching short videos. At the end of this module there will be an electronic link to other modules about Coastal Saltmarsh, Giant Freshwater Crayfish and Little Penguins.
What are Short-tailed Shearwaters?
The Short-tailed Shearwater is the most abundant seabird species in Australia. It breeds in southern Australia but is most abundant on small islands around Tasmania, particularly, Bass Strait Islands. There are also smaller breeding colonies on Tasmanian headlands. After breeding throughout the Australian summer months, it migrates to the Bering Sea in the Northern Hemisphere. It is one of the world’s most amazing migratory birds.
The scientific name for the Short-tailed Shearwater is Ardenna tenuirostris. yolla and moonbird are the names that Tasmanian Aboriginal people use and gave to this amazing creature. The Short-tailed Shearwater is also commonly referred to as the muttonbird.
Short-tailed Shearwaters are dark smoky-brown in colour, with slightly paler underwings. Their tail is short and rounded and their bill is dark and slender.
Adult Short-tailed Shearwaters weigh about 500 grams and have wingspan of about 1 metre. Growing chicks can weigh over 1kg before fledging (developing feathers). They have webbed feet to assist them with swimming and are often seen feeding off the shores of Tasmania in large groups.
Image credit: Ed Dunens
Where do Short-tailed Shearwaters live?
Arriving in Australia in late September Short-tailed Shearwaters live and breed mostly on small islands, or from New South Wales to Western Australia, with most living in the Bass Strait. While in Australia adult birds can undertake short foraging (fishing) trips around the local area but some trips can reach as far as Sub-Antarctic waters. Adult birds leave Australia in March/ April and head to Sub-Antarctic waters to feed for up to a month before migrating north, flying past Japan to the rich, cold water feeding grounds of the Bering Sea near Siberia and Alaska. They can migrate from the Bering sea to Australia in a little as two weeks.
Chicks however don’t leave their colonies until late April/early May and immediately head north. From September, their migration route requires them to fly up to a staggering 30,000 kilometres each year.
What does their habitat look like?
It is estimated that up to 18 million Short-tailed Shearwaters arrive in Tasmania each year to breed. They return to their colonies which are usually located on headlands and islands where they can easily land and take off.
Typically, their colonies are covered with tussocks and succulent vegetation such as Iceplant and Pigface, where they make their burrows. There are around 209 Short-tailed Shearwater colonies in Tasmania, with an estimated 11.4 million burrows.
Image credit: Rose Grant.
What do Short-tailed Shearwaters eat?
Short-tailed Shearwaters hunt krill, squid and fish by:
- plunging underwater
- pursing prey under water
- seizing prey on the water’s surface
- scavenging
- hydroplaning
- bottom feeding
They are very capable swimmers and are able to dive over 20 metres below the surface of the water. They use their hooked beak to hold on to their prey. During the breeding season, adults mostly feed near the colony but can travel as far as Sub-Antarctic waters and when they return, they regurgitate their catch into the beaks of their chick.
Image credit: Duade Paton.
Have a look at how Short-tailed Shearwaters hunt bait fish underwater
When do they breed?
Short-tailed Shearwaters return from their migration in the Northern Pacific, in late September/early October. They return to their burrow where they reunite with their breeding partner and scratch out and refurbish their burrow (or make a new one) where they breed. Only mature birds breed, usually around 7 years of age (from 4 to 15 years). Burrows are around 1 metre long. Once they have bred, they fly as far as the Sub-Antarctic to gain condition. Peak laying of a single egg occurs around the 28 November.
Short-tailed Shearwater (Ardenna tenuirostris) burrow. Image credit: Rose Grant
How cute is this little chick!
Once the egg is laid, the female will depart the burrow to feed for two weeks while the male incubates the egg, from there on both the male and female taking turns incubating. When the parent is incubating the egg in the burrow, it doesn’t leave the burrow, nor is it fed by its mate. After around 53 days (usually in the third week of January), the chick hatches. Now both parents leave to forage during the day and come back to feed the chick at night, however as the chick gets bigger foraging trip duration increases. It grows quickly, until it is almost double the weight of an adult.
Image credit: National Parks NSW.
Take a look at a Short-tailed Shearwater burrow, the parents and their chick
Chicks get left behind to fend for themselves
In early April, the chick’s parents leave their nesting sites to feed up for a month in the Sub-Antarctic before heading north for their migration. For breeding adults, this routine can be repeated up to 34 times, as adults can live up to 38 years of age.
When the Short-tailed Shearwater parents leave their chicks behind to fend for themselves, the chicks are still covered in down. Over the next two to three weeks, the chicks increasingly spend more time outside their burrow, exercise their wings and lose their down and grow feathers. They become a fledgling (ready to learn to fly), lose weight and move closer to the shore. Finally, they fly away and begin their first migration north, on their own without any assistance.
Fledging Short-tailed Shearwater (Ardenna tenuirostris). Image credit: JJ Harrison.
How tricky is migration?
The first migration is risky for fledglings, as they already have lost weight and can become exhausted and starve during their maiden journey north. The time that Short-tailed Shearwaters spend away from colonies varies according to their age. Birds that have fledged and are not yet mature enough to breed spend the least time in breeding colonies.
Protection under environmental legislation
The Short-tailed Shearwater is protected under the Japan–Australia Migratory Bird Agreement (JAMBA), which provides for the protection and conservation of migratory birds and their important habitats. Migratory species are not only protected under international agreements, but also under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
Wildlife reserves have been established to protect Short-tailed Shearwaters which are listed as ‘least concern’ under the IUCN Red List.
The muttonbird harvest
The Tasmanian Aboriginal people have been harvesting Short-tailed Shearwaters (muttonbirds) and their eggs for countless generations.
Today the muttonbird harvest (‘birding’) is an important cultural practice for Tasmanian Aboriginal people, who value the harvest as a being a significant spiritual and cultural rite. Recreational harvesting of shearwaters of around 40 colonies, in Bass Strait and the west coast, is open each year. Shearwater chicks are commercially harvested in Tasmania at Babel, Great (or Big) Dog and Trefoil Islands.
Aboriginal families have special permissions to continue harvesting muttonbirds (yolla or moonbirds) for personal and commercial use. The chicks are taken for their feathers, flesh and oil.
Have a look at this historic but interesting video about the muttonbird harvest: The Mutton Birds of Bass Strait (1956).
mulaka yula Hunting Muttonbirds on Great Dog Island. Image credit: Larila images.
Short-tailed Shearwater wrecks
Short-tailed Shearwaters are washed up dead on Australian shores, particularly down the eastern seaboard, every year. These events are called ‘wrecks’ and can range from hundreds to thousands of birds.
Numbers washing up from year to year vary greatly. The deaths are thought to be caused by loss of condition, variable food availability, and sea and wind conditions that blow onshore.
The deaths could also be linked to the abundance of wild salmon, which compete with shearwaters for the same food sources. The diets of some salmon species and Short-tailed Shearwaters overlap.
Wrecks of Short-tailed Shearwaters in Australia and Tasmania have been reported since the 1800s. They are often found in the Spring on the east coast of Australia. This is when the birds are migrating south to return to nesting colonies, which requires a huge amount of energy. Birds that successfully migrate have big fat reserves that they use as they fly, but the dead birds found in wrecks (or observed sitting on the water unable to fly), are emaciated.
As sad as these wrecks are, they are probably natural events. Collection of data on shearwater deaths is important to be able to understand just how many die each season and what this means to overall numbers.
If you sea dead shearwaters on a beach, record details of the date, time, beach name, location and number of birds. You can email this information to atlas@birdlife.org.au with ‘Shearwater Wreck’ in the subject line.
DPIPWE is also interested in reports of wrecks. Sightings of large numbers of dead shearwaters (or other species) can be reported to the Marine Conservation Program via the 'Whale Hotline' on 0427 WHALES (0427 942 537).
Image credit: Donald Hobern.
What are the greatest threats to Short-tailed Shearwaters?
Habitat destruction
Over-harvesting
Fire
Plastic debris
Feral cats
Human interference
Grazing
Light pollution
Climate change
Variability of food sources
Habitat destruction
Coastal development and land clearing continues to place pressure on Short-tailed Shearwater habitat.
Recreational vehicles pose a threat to colonies, as vehicle tracks cause soil erosion and compaction, making sites unviable for burrowing.
Over-harvesting
Whilst commercial and recreational licenses are required to hunt Short-tailed Shearwaters, illegal poaching takes place.
Fines of up to $6,000 can be issued for poaching Short-tailed Shearwaters.
For information on Recreational Game licenses:
Fire
Short-tailed Shearwater colonies rely on adequate vegetation cover and good soil structure that allows birds to maintain and create new burrows. When vegetation is burnt by fire, it leaves the soil exposed, and subject to erosion. Bare, compacted sites then become compromised and unsuitable for burrows.
Plastic debris
Plastic debris poses a real threat to Short-tailed Shearwaters. While they are at sea, birds inadvertently ingest small plastic pieces which they confuse with prey. When a bird ingests plastic, it can cause starvation, as the plastic can perforate, block and impair their digestive system. It can also release toxic pollutants.
Fledging chicks are at a greater risk than adults, as parents regurgitate plastics to chicks, causing internal ulceration and reducing their food intake. This means that chicks do not receive enough nutrients, and their risk of starvation increases.
Researchers are concerned that with the increase of plastic ingestion by Short-tailed Shearwaters since the 1970’s, that long term harm to their life cycle, reproduction and populations is yet to be fully understood.
For more information about the negative impacts of plastic debris on Short-tailed Shearwaters click below:
Feral cats
Short-tailed Shearwater chicks are easy prey for feral cats.
Cats are skillful, adaptive predators and are known to impact negatively on ecosystems globally. Short-tailed Shearwater chicks, and adults, are no match for feral cats, as they do not have the defence mechanisms to fend off such dominant predators.
Take a look at recent research about how feral cats prey Short-tailed Shearwaters:
Human interference
Short-tailed Shearwater burrows are excavated into soft soil and are therefore fragile. Burrows can easily collapse if humans walk on them. If a burrow collapses under the weight of a person, then eggs or chicks can be trampled and injured.
Grazing
Unfortunately, some Short-tailed Shearwater colony sites are not protected and are on privately owned land where cattle, sheep and pigs graze. Whole colonies have been destroyed by stock trampling nest sites and over grazing of vegetation cover.
Light pollution
This causes birds to become disorientated and crash into infrastructure or during misty nights they lose sight of the horizon and simply circle until they are exhausted or crash into infrastructure.
Climate change
Variability of food sources
The natural predators
Pacific Gulls, Kelp Gulls, ravens, Tasmanian Devils and even possums have been known to prey and raid seabird colonies for eggs and young eat carrion or live prey.
Natural mortality
The greatest risk for natural mortality of Short-tailed Shearwaters is during the first migration due to exhaustion and starvation. The ingestion of plastics, or reduced availability of their target limits their ability to maintain condition and contributes to their death while migrating.
What can I do to help keep Short-tailed Shearwaters safe and healthy?
Avoid walking through sensitive Short-tailed Shearwater colonies
View Short-tailed Shearwaters only at designated areas
Protect Short-tailed Shearwater colonies on reserves or your own land to help maintain habitat
Don’t drive recreational vehicles through colonies
Keep your cat safe at home or in an outdoor enclosure
Do your bit to reduce marine debris - take your rubbish home, join in local beach clean-ups and get involved in ‘Plastic Free July’ and ‘Take 3 for the Sea’
Don’t burn off vegetation near colonies
Support local efforts to conserve threatened species in your area by joining a local Coastcare, Landcare or a 'Friends of' group
Join BirdLife and participate in bird counts
Participate in special community events, information nights, tree planting days and weed eradication programs
If you plan to harvest muttonbirds, obtain a muttonbird licence, and only take what your permit allows
Fence off colonies to prevent stock from trampling burrows and grazing on vegetation that maintains soil structure
What is ‘take 3 for the sea’?
‘Take 3 for the sea’ is global movement aimed at inspiring you to take 3 pieces of rubbish with you when you leave the beach, waterway or anywhere.
What is Plastic Free July?
Launched in 2011 by Perth's Western Metropolitan Regional Council, Plastic Free July aims to educate the public on the problems plastic causes. Click below to find out more.
Remember the 3 Rs?
You will probably remember learning about the ‘3 R’s’ when you were growing up; reduce, reuse and recycle. This philosophy is still important today, and even more so with the ever-increasing negative effects that plastics are having on our marine environment.
Want to do your bit to reduce plastic debris before it enters our oceans?
Take a look at this infographic to learn about the impacts of plastic debris and how you can do your bit to reduce plastic debris from entering the ocean:
Want to know what’s happening in our region to fight marine debris?
Want to go ahead and join a group and make a difference?
You can make difference by participating in Coastcare projects
or find a Coastcare group near you
Why not get involved in Cradle Coast NRM Regional Land Partnerships?
If you live in one of the priority catchments that Cradle Coast NRM will be working in, you have an opportunity to get involved in one of our Regional Land Partnerships projects. Contact Cradle Coast NRM for more information
Before you go, let’s recap on the key learnings from this module. In this module, you have learnt about the Short-tailed Shearwater
- Their habitat and ecology
- The greatest threats to Short-tailed Shearwaters
- How you can help reduce threats to Short-tailed Shearwaters
You will have learnt about the options for getting involved to make a difference
Join a local Coastcare group here
Get involved in one of our Regional Land Partnerships projects. Contact Cradle Coast NRM for more information
If you want to know more about Short-tailed Shearwaters and how you can get involved, contact Cradle Coast NRM
Are you interested in learning about other important species in the Cradle Coast region?
We have developed other online learning modules
COASTAL SALTMARSHES
GIANT FRESHWATER CRAYFISH
LITTLE PENGUINS
Credits:
Created with images by Igor Chaikovskiy - "Flight of proud petrel" • Wirestock - "Sooty shearwater flying over the water, Northern Vancouver Island, BC Canada" • 13082 - "penguin fairy penguin bird" • 11066063 - "penguin zoo bird" • Aarón Blanco Tejedor - "untitled image" • Ryan Walton - "untitled image" • Tito Rebellious - "untitled image" • Almos Bechtold - "untitled image" • bilyjan - "guise plastic waste" • dimitrisvetsikas1969 - "cat feral outdoor" • Jacob Miller - "untitled image" • Elias Carlsson - "untitled image" • Robert Bye - "untitled image" • Trevor Cole - "untitled image" • Vladvictoria - "aquarium salmon water" • PixbayBlade - "australia tasmania zoodoo" • Jeremy Bishop - "untitled image" • LuizAntonio - "pollution teddy bear beach" • Imogen - "Flesh-footed shearwater - Puffinus carneipes" • Anastasiia - "A flock of Manx shearwater in the sea" • Wil Stewart - "untitled image" • NeONBRAND - "untitled image" • 9dreamstudio - "Template for contacts, background for contact information. Lettering Contact us in notebook on office work desk with computer on dark wooden background top view space for text" • geralt - "silhouette head bookshelf"