Northern giant petrels (NGPs) are one of two giant petrel species that breed on Macquarie Island, the other being the southern giant petrel. NGPs are listed as a rare and vulnerable species under state and federal legislation, respectively.
NGPs breed in scattered colonies or solo on the majority of Macquarie Island’s coastal terrace and small onshore rock stacks. Historically the population has suffered mortalities from the long line fishing industry and pest predation on the island. More recently, the population was impacted by secondary poisoning (through scavenging on poisoned rabbit/rodent carcasses) during the Macquarie Island Pest Eradication Program (MIPEP), and a key aim of the annual NGP monitoring program is to document the recovery of the species following this event.
Every year, nesting NGPs are surveyed within an established north-west census area that runs from the northern end of the Featherbed track to Flat Creek, covering the entire northern featherbed special management area (SMA) and part of the southern featherbed SMA. While there are NGPs found all around the island, it isn’t feasible to survey the entire population annually. It has been shown that the north-west census area provides a statistically representative sample from which to extrapolate population trends to the entire island population.
This year the Macquarie Island Albatross and Giant Petrel Monitoring Program research assistants, Emily and Mel, in conjunction with Tasmanian Parks and Wildlife Service (TasPAWS) rangers, Andrea and Penny conducted the census between the 5th–13th of September. They were ably assisted in the field by volunteers Kerri, Matt and Emry from the Bureau of Meteorology (BOM), Wayne and Geoff from the trades team and Nick the chef.
The census area is divided into four sections and involves thorough searching within every inch of the survey areas. All nests are located and marked and contents recorded (i.e. bird on egg, bird on nest or empty) for a follow–up chick census in January which will provide information on breeding success and allow for chick banding.
The incubating adults were also approached for band reading. Band resighting allows us to investigate adult survival, individual breeding frequency, breeding performance and site fidelity between years.
The featherbed is a vast waterlogged area along the coast comprised of a deep boggy peat bed covered in what feels like a layer of floating vegetation. In some areas you may feel as though you are gently bouncing along a springy waterbed, whereas other areas you may accidentally take a wrong step and fall waist deep into bone-chillingly cold freshwater.
The coastal edge is dominated by large tussocks with stinky bogs scattered in between. The points along the coast turn into a maze of massive sea stacks. Wandering among these can make you feel as though you’ve become lost in a magical world of colobanthus staircases and enchanted pools. Sometimes you totally forget the very reason you are there — to look for NGPs!
From a preliminary look at the results, it appears the breeding population is continuing to increase — some positive news for our feathered friends!
Mel Wells & Emily Mowat
