In October 2013, dead shearwaters (Puffinus spp.) were washing up along beaches and coastlines from Queensland to South Australia, Western Australia and Tasmania. The majority of the birds were short-tailed shearwater (Puffinus tenuirostris). Short-tailed shearwaters are a widespread, abundant seabird species, with a worldwide population in excess of 18 million animals. They spend approximately six months in Australia nesting and breeding before returning to their wintering grounds in the northern hemisphere in April. A number of other shearwater species were also been reported washed up on beaches, including: wedge-tailed (P. pacificus), fluttering (P. gavia) and flesh-footed (P. carneipes).
The conclusion was that this is a ‘natural but unfortunate event, with birds having died from exhaustion and starvation, following their long annual migration from the northern hemisphere to nesting areas in the southern hemisphere. Birds are often in poor condition and have limited energy reserves, having travelled over 15,000km. Die-offs occur annually, however this year has seen an extensive and widespread number deaths. Severe weather and difficulty finding sufficient fish stocks during their migration are considered to be contributing factors.
Potential for diseases to be involved a part of the cause of the mortalities was investigated; a number of birds were submitted for necropsy from a number of locations in Qld, NSW, Vic, Tas and WA. All have showed similar results, including muscle wasting, emaciation and evidence of starvation. Some infectious diseases including avian influenza and Newcastle disease were excluded by PCR in the events in NSW, Vic, Tas and WA. Infection with West Nile Virus was also excluded by PCR in birds from NSW.
If you see a large number of dead birds on a beach, you can report the incident to your state or territory WHA Coordinator. If you find any live birds that are obviously unwell or injured, please contact your local veterinarian or wildlife carer group for advice.
WHA related resources and advice
Note: WHA would like to thank all those who submitted information, including our subscribers, state and territory WHA coordinators, university researchers and zoo veterinarians.