Rob Morris of Southern Ocean Seabirds Association gave the July presentation, illustrating the talk with his many wonderful photographs depicting the birds he has seen through the seasons. Images are from his presentation.
Southern Ocean Seabirds Association (SOSSA) is an international not-for-profit organisation which encourages research into sea birds. www.sossa-international.org Members and visitors travel from Southport out to the continental shelf every month on the Grinner, a 15 passenger boat. There they record species and gather data which charts the diversity of species in the region. About 30 nautical miles offshore, the seafloor drops suddenly 4000 metres, then rises to 300 metres below the surface at the Britannia Tablemount, causing a welling up of nutrients which attract seabirds. The Eastern Australian Current (EAC) flows all year down the coast but is more prevalent in summer. There are other currents as well (e.g. South Equatorial Current, Tasman Front) which affect the migration of fish. SOSSA monitors the currents and water temperatures through the seasons.
The Grinner leaves about 6.00 am and heads east, noting inshore species. They spend some time in the open sea, leaving about 1.00 pm to return to Southport at 4.00 pm. They use burley to attract fish and record the seabirds seen. They usually see 15-20 species per trip, but have seen 80 species in 20 trips. A perfect day has 10-15 knot south-easterly winds. Strong south-east winds bring out interesting species. The boat does not go out in winds over 23 knots.
Summer (Dec – Feb) Sea temperatures are warm (24-28°) and a strong EAC flows north to south. Winds are variable but a good wind brings many birds – summer breeding species, summer visitors and tropical visitors. A small selection of those he showed were:
- Tahiti petrels, which breed in New Caledonia
- Flesh-footed shearwaters, whose closest breeding ground is on Lord Howe Island
- Red-tailed tropic birds, which breed on Lady Elliot Island.
Autumn ((March to May) Water is still quite warm (24-27°) and the EA current is still noticeable. Westerly winds increase in May when winter visitors start arriving and tropical visitors disappear. A few from his autumn sightings were:
- Providence petrel, from Lord Howe Island. These birds were once common on Norfolk Island where their presence saved the new colony from starvation, at the expense of their local extinction – hence the common name.
- Kermedic petrel, only found on Bells Pyramid near Lord Howe Island
- A rare sighting of a Bridled tern.
Winter ((June-Aug) Water temperature is cooler (18-22°) with the EAC weaker. Westerly winds increase and winter storms affect what birds are seen. Southern Ocean species arrive. Winter is the best time to see albatrosses in Queensland and a good range of albatrosses can be seen, mostly young adults and juveniles. A few winter birds he features were:
- Black browed albatross
- Buller’s albatross
- Shy albatross
- Antarctic Cape Petrel was seen for the first time this year
Spring (Sept-Nov) Water temperatures continue to rise through spring (20-25°) and the EAC strengthens. Westerlies decrease. There is a big southbound migration. Some of the birds he showed were:
- Short-tailed shearwater, seen in their thousands,
- Cape petrel, still around after winter,
- South Pole Skua, our most southerly visitor,
- Pomarine skua (or Yager) from Siberia.
Rob concluded his presentation with pictures of other animals seen on these Pelagic trips – whales, including melon-headed whales and dolphins . Answering a question from the audience, he said that March can be the best time to take this trip because there are likely to be both summer and winter birds.