The 2011 wreck is likely to be the largest seabird wreck in New Zealand history. (26 July 2011)
The storm wreck mainly affected Prion species, including Broad-billed, Salvins, Antarctic, Fairy, Fulmar, and Thin-billed Prions.
This small blue-grey seabird, weighing 120gm - 200gm (depending on species), breeds in New Zealand waters, but the beach wrecked birds may also be from larger colonies in the South Atlantic and Indian Ocean islands.
The New Zealand populations of prions breed mainly in the sub-Antarctic islands, including about one million Broad-billed Prions that breed on the Chatham, Snares, and Stewart Islands and around the Fiordland coastline. This population was expected to be particularly hard hit by the beach wreck.
Hundreds of thousands of Prions Die
Ornithologists in New Zealand estimate that between 226,000 and 428,000 prions were killed in the storm with the most likely figure around 350,000. This is estimated from recoveries of dead birds along many kilometres of coastline, mainly on the west coast of the North Island.
Prions were washed up on the beaches from around July 4th to 22nd with the peak around July 15 -17. Hundreds of exhausted Prions found on beaches and coastal farmland were also taken into care for rehabilitation with most at Wellington Zoo and at Massey University in Palmerston North. The birds were exhausted and hypothermic and were being kept warm and fed on fish slurry prior to release.
“The scale of the 2011 wreck in unprecedented,” said seabird scientist, Dr. Graeme Taylor from the Department of Conservation, who was carrying out research at a Grey-faced Petrel colony at Bethells Beach on the west coast at the time (he was reporting the event on Birding-NZ ).
He picked up 589 dead birds over 2.5 km of Bethells and O’Neills beaches (west coast north of Auckland). All were prions except three Diving petrels and a Blue penguin.
Scale of Wreck Unprecedented
“The scale of the wreck was unimaginable,” he said. “In places I had five to six birds within a metre of each other and sometimes piled up about 50 birds from a small patch to process them and move on. Sand clogged corpses are quite heavy even if the birds themselves were pretty light.”
On these two beaches, the break-down of the six species found was Broad-billed prion 450, Salvins prion 21, Antarctic prion 53, Fairy prion 11, Fulmar prion 35, Thin-billed prion 6, and other Prion species 9.
“The number of Broad-billed prions washed ashore is exceptional,” said Dr. Taylor. “Previous large wrecks included 1385 in 1961 and 1175 in 1974.”
The Prions were found at a rate of about 180 per km on Bethells, but this would have been higher, around 200 per km, if he had time to finish the third sweep of the beach on Friday.
Broad-billed Prion Population Threatened
At that rate about 20,000 Broad-billed Prions had probably perished per 100 km of coastline. Given reports of Prion wrecks from the west coast of the South Island to Northland suggested well in excess of 100,000 Broad-billed Prions had probably perished in this single storm event.
The other major wreck was Fulmar Prions, said Dr Taylor. The 35 found on Bethells compared with the previous highest annual total of 63 found on all New Zealand beaches during 1985. Only 101 were found from 1960 to 1986 in total.
The 2011 wreck of Fulmar Prions was at a rate of 14 per km and an estimated 1400 per 100 km. The identity of Fulmar Prions needed to be checked very carefully, he said. Fulmar Prions had a large top hook, and comparing Fairy and Fulmars in the hand, the unguis hook of Fulmars was about twice the size of Fairy Prions.
The 2011 wreck was likely to be the largest in the history of the Ornithological Society of New Zealand beach patrol tallies, said Dr. Taylor. People needed to gather up the corpses and talley up the numbers. In 1985, the previous highest annual total was 28,304 birds. There would be more than that number on our beaches at present, but it needed OSNZ beach patrollers to count them before they disappeared under the sand.
