12 May 2012 Report


Birders who go out regularly on pelagic trips tend to develop theories which would explain how conditions are likely to affect the number of birds or species seen on a particular day. Most of these theories are empirical and usually turn out to be specious as well, such as "the further we go out beyond the shelf break, the more species we are likely to see". We have debunked that one on a few occasions along with any number of theories on "unseasonably warm water" and "unseasonably cold water", although these theories do still get a regular run on the Halicat. However, on this trip,we debunked one of the really strongly held theories which says that, when it is cold, windy and rough, it may be unpleasant for the birders but you will always see heaps of birds. We had strong south westerlies all day with quite an unpleasant short period chop and our total species count was 12, our lowest for at least two years. This is not to say that it was an uninteresting day on the water (that is never the case!) as we had short but good views of a Black-bellied Storm Petrel, extended views of a pod of hunting False Killer Whales and a close up view of Australasian Gannets diving into a bait ball. Surface water temperatures were a little cooler than they were a month ago being 18.8 deg C at Sydney Heads and rising to 19.9 deg C off the continental shelf. We departed from Rose Bay at 7.10am and returned at 3.45pm. With a strong south westerly of 20 - 25knots blowing all day, sea conditions became more uncomfortable as we headed further east with a 1.5m southerly swell and an unpleasant 2.0m sea on top of that. As a result of these conditions there were a few cases of sea sickness on the boat.


We headed out of the harbour with a complement of 18 passengers on board and with David James back at the berley table after his trip to Christmas Island. With all the shearwaters having left for their winter quarters, it was difficult to get any great interest in the berley trail as we left the heads but we did have the strange phenomenon of the Silver Gulls staying with the boat all the way to Brown's Mountain, the first time that we could recall this happening. After encountering a small pod of Short-beaked Common Dolphins just off the heads, we had a fairly quiet ride out to the shelfbreak, seeing a few Australasian Gannets, an increasing number of Black-browed Albatross, a Fluttering Shearwater and a couple of Short-tailed Shearwaters. As we reached the continental shelf drop off, we saw our first Providence Petrel of the day and, surprisingly, we saw very few more during the trip. We set up a berley slick near Brown's Mountain and soon attracted good numbers of Black-browed Albatross which were joined by smaller numbers of Yellow-nosed Albatross. A Sooty Shearwater fed around the boat for a while, a White-faced Storm Petrel was seen at some distance and did not linger, and a Southern Ocean Sunfish (Mola Raysayi) was seen making its way across the slick. After motoring back up the slick and starting a second drift failed to attract any new species, we moved inshore by a couple of kilometres and started another berleying session. Again, the same group of birds seemed to move to the new location to join us but, in addition, a single Great-winged Petrel added to the species count. We then commenced a slow run back to Sydney against the south westerly wind and almost immediately encountered a 'fregetta' storm-petrel which gave only brief views before it headed away from the boat. Fortunately, Raja obtained a very good diagnostic photo showing the bird to be a Black-bellied Storm Petrel which avoided the need to show only 'fregetta (sp)' in the trip report. Probably the most absorbing event of the day was when we encountered a pod of about 30 False Killer Whales which appeared to be hunting. There were a few Short-beaked Common Dolphins in the vicinity but it was unclear whether they were prey or were just associating with False Killers. The last event of the day was the discovery of a circular, bright red, bait ball several metres in diameter near to the water surface. A few Australasian Gannets gave us a close view of them spearing into the bait ball and catching the long beaked fish. See Raja's photographs at http://www.adarman.com/Pelagics/2012...950158_75vHZz#!i=1844330711&k=5PjzfvQ Except for those who were seasick, it was a very enjoyable day on the water with plenty to keep interest levels high. By the way, I have new theory which goes "When it is cold, windy and rough you see a lot more birds than on a calm day BUT only when the wind is onshore (i.e. from the easternquadrant)......"


(Note that the numbers in parentheses represent the approximate maximum number of that species in view at one time)

Great-winged Petrel 1 (1) gouldi
Providence Petrel 6 (2)
Sooty Shearwater 2 (1)
Short-tailed Shearwater 4 (2)
Fluttering Shearwater 3 (1)
Black-browed Albatross 26 (15) two impavida
Indian Yellow-nosed Albatross 3 (2)
White-faced Storm Petrel 1 (1)
Black-bellied Storm Petrel 1 (1)
Australasian Gannet 17 (6)
Silver Gull 90 (50)
Crested Tern 7 (2)


Short-beaked Common Dolphin 8
False Killer Whale 30
Southern Ocean Sunfish 1