48th annual report for NIE

Published in Nature in Eurobodalla vol. 21 (2006) pp 67-71 - but issued November 2007

48th ANNUAL ASSESSMENT OF SHEARWATER BREEDING SUCCESS ON MONTAGU ISLAND,

27 MARCH – 3 APRIL 2007

Format of this report and the abbreviations used therein are consistent with those in previous annual reports (e.g. Crowley et al. 2006). The study area on the south-eastern side of the smaller northern part of Montagu Island is known as NISA (293 m2); the two study areas at the northern end of the southern part are known as SISA (428 m2) and THISA (293 m2). Their position is shown on the maps in the report on the size of the shearwater breeding population on Montagu Island (Fullagar and Heyligers 1998). The bird records for the island have been reviewed by Fullagar (1989). Names of vertebrates follow Clayton et al. (2006), those of vascular plants Heyligers and Adams (1989, 2004).
Weather and Habitat Conditions
We departed Narooma at 0900 on 27th March, through calm, windless seas with a low 1-2 m easterly swell. Sea remained calm during the first two days of our stay. The weather was generally clear and calm with light southerly breezes on 27th and 28th. On 29th, strong north-east wind with light rain delayed our start to the North Island study area until 1030. The wind swung round to the south during the afternoon with some late squalls of rain. Upon arrival on the 27th we commenced work on THISA at 1155 and finished at 1445. On 28th we began work on SISA at 0900 and finished at 1355. On 29th we departed for NISA at 1100, started the survey at 1150 and finished at 1730. On 1st April we conducted the usual general wildlife survey of the island.

Rainfall was average in January with slightly higher than average falls in February and March. This ensured that the vegetation on the study areas was lush. Spiny-headed Mat-rush Lomandra longifolia, Bracken Pteridium esculentum, Scurvy Grass Commelina cyanea and Kidney Weed Dichondra repens were in good condition. Runners of the Red Kennedy Pea Kennedia rubicunda were also thriving and continue to invade the north-eastern side of SISA. On NISA most tussocks of Spiny-headed Mat-rush, Tussock Grass Poa poiformis and Knobby Club Rush Isolepis nodosa were also in good condition. While only small amounts of Rambling Dock Acetosa sagitata were present in SISA, it is still widespread on both North and South Island and has the potential to become a problem in the future. Common Milk Vine Marsdenia rostrata is becoming more widespread on South Island. Kikuyu Grass Pennisetum clandestinum was absent from SISA although some active runners were noted on the adjacent cliff face.

We departed the island at 1200 on 3rd April, after carrying out a count of the seals on the north-east side of North Island from the sea. A few shearwaters – short-tailed, wedge-tailed and fluttering – as well as several gannets, gulls and crested terns were observed on the return trip in almost windless conditions with a low south-easterly swell.

Survey Team
This year’s team comprised Peter Fullagar, Michael Crowley and Chris Davey (MIPartners), Nicholas Carlile (Dept. of Environment and Conservation), Amy Jorgensen (NPWS), Frances Cory (Charles Sturt University), Vanessa Place and Paula Pollock.

Survey Results
The results of this year’s survey, together with those of last year, are summarised in Table 1.

Table 1. Number of shearwater chicks and number of burrows found in the three study areas this year and last year (figures in brackets), together with the totals for both years.

The number of Wedge-tailed Shearwater Puffinus pacificus chicks was higher than those in the previous breeding season on all three sites. It exceeded the long term average of 10.8 on SISA and 32.5 on NISA and was close to the long term average of 11.6 on THISA. In stark contrast to the previous year, the general condition of birds was very good with the mean weight of the 80 chicks being 521 gram, compared to 395 gram in 2006. Seventy two of the eighty chicks were completely covered in down.

Short-tailed Shearwater P. tenuirostris chick numbers were also higher than those in the previous breeding season. On NISA they were similar to the long-term average of 35.8, but on SISA numbers were below the long-term average of 60.5, while on THISA they were slightly above the long-term average of 17.8. The general condition of this species was good with the mean weight being 650 gram; 20% of chicks were still completely down covered.

One Sooty Shearwater P. griseus chick (850 gram) was found on SISA.

General observations of birds, mammals and reptiles
Experimental study plots, set up to investigate re-vegetation procedures on Montagu Island, are scattered along the pathway leading to South Landing and also beyond to the south end of the island. More than a dozen such 20x20 metre plots occur containing a wide variety of regrowth conditions. However, most of these plots do provide 'islands' of denser vegetation acting as useful alternative habitat with, in some areas, the vegetation reaching a maximum height of about three metres. The whole western side of the South Island between the South Landing and the Jetty has been replanted and a strip of dense Coastal Wattle Acacia longifolia var. sophorae now borders the western side of the track between these two locations. We refer to this area as the Acacia thicket.

Birds
Apart from observations made while on the study plots we explored both North and South Island on the 1st April.

Little Penguin Eudyptula minor. Little activity ashore, but there were the occasional calls of individuals at sea during the day. No counts were made of birds coming ashore in the evenings.

Black-browed Albatross Thallasarche chlororhynchos. One observed following a trawler during crossing to the island on 27th.

Wedge-tailed Shearwater Puffinus pacificus, Sooty Shearwater P. griseus and Short-tailed Shearwater P. tenuirostris. See text above. Only small numbers of Wedge-tails and Short-tails seen at sea in daytime. Fluttering Shearwater Puffinus gavia. A few at sea were recorded most days.

Australasian Gannet Morus serrator. A large group of several hundred observed flying north ahead of southerly change on 28th, about 10% immatures. As well, small numbers seen every day, both adult and immatures. Little Pied Cormorant, Phalacrocorax melanoleucos. One observed each day with Great Cormorants. Great Cormorant Phalacrocorax carbo. Seen every day but few present with maximum number of ten seen on rocks near south landing during morning of 2nd April.

Black-shouldered Kite Elanus notatus. One seen on South Island 27th Mar - 1st April. Two birds displaying over South Island on 2nd April. White-bellied Sea-Eagle Haliaeetus leucogaster. Observed every day with a maximum of four individuals, aged as two adults, one near adult, one 2nd year. Brown Goshawk. Accipiter fasciatus. One seen near Acacia thicket on 1st and 2nd April. Swamp Harrier Circus approximans. One bird observed every day. Peregrine Falcon Falco peregrinus. Male and female seen most days. No evidence of breeding success. Material collected from nest site on North Island. Nankeen Kestrel Falco cenchroides. Observed every day. Three in one group on 27th.

Buff-banded Rail Gallirallus philippensis. Few seen or heard. Eight noted on South Island on 27th.

Eastern Curlew Numenius madagascariensis. One observed flying east over island on 1st April. Sooty Oystercatcher Haematopus fuliginosus. Maximum of eight birds seen during simultaneous count on 1st April. One adult with a juvenile still being fed observed at SE corner of South Island. Two adults with juvenile on NE corner of North Island, one pair in SW corner of South Island and one bird noted on the east side of South Island. Twelve recorded on South Island on 2nd April.

Silver Gull Larus novaehollandiae. Small numbers observed at sea and around island every day. Four adults with runners: 2 x 2 at landing, 1 x 2 on rocks north of landing and, at lightstation, adult with two runners, one of which died during survey. Caspian Tern Sterna caspia. One seen on 28th on west side of South Island. Crested Tern Sterna bergii. Few seen at sea and one to five present with cormorants on rocks on west side of South Island each day.

Yellow-faced Honeyeater Lichenostomus chrysops. Individual birds recorded in Acacia thicket on 1st and 2nd of April. Grey Fantail Rhipidura fuliginosa. Maximum of three in Acacia thicket on 30th. Australian Pipit Anthus australis. Three observed. Two often around light station and one seen at south end on 27th.
Welcome Swallow Hirundo neoxena. Two seen each day. Individuals seen on both islands. Little Grassbird Megalurus gramineus. Calls heard on several days at one location. Five flushed on North Island during survey on 1st April. Golden-headed Cisticola Cisticola exilis. Not vocal and difficult to detect but a few birds evidently present. Silvereye Zosterops lateralis. Small parties heard all days; mainly moving north. All birds observed were the Tasmanian sub-species.

Mammals
House Mice Mus musculus. Regularly seen throughout both islands as well as in the buildings. Not as prolific as in 2006. Frances Cory (CSU) carried out a trapping program on both islands during our survey prior to proposed mouse eradication that is to be carried out during the winter of 2007. European Rabbits Oryctolagus cuniculus. None observed and signs of activity restricted to a few dung hills on the north end of North Island.

Seals.
About 150 seals estimated to be present on the island. Australian Fur Seals Arctocephalus pusillus doriferus and New Zealand Fur Seals A. forsteri were observed but no count of individual species was attempted. Four pups were seen during the survey, but at least eight pups, believed to be New Zealand Fur Seals had been counted during the summer (M. Westwood, NPWS, pers. comm.) indicating that breeding is now regularly occurring. Australian Sea Lion Neophoca cinerea. One individual identified with fur seals at haul out site on north western side of North Island on 3rd April. Species previously recorded in 1998 (Shaughnessy et al. 2001).

Reptiles
Both species known to occur on the island, White’s Skink Ergenia whitii and Grass Sun-skink Lampropholis guichenoti, were observed throughout the island.

Acknowledgments
We are indebted to the NSW National Parks and Wildlife Service for hospitality while on the island and thank Preston Cope, Ross Constable and Paul Bourke for assistance with transport. The efficient contribution of the other team members has in no small measure contributed to the speed and success of the survey this year and is gratefully acknowledged.

References
Clayton, M., J.C. Wombey, I.J. Mason, R.T. Chesser and A. Wells (2006). CSIRO List of Australian Vertebrates – A Reference with Conservation Status. CSIRO Publishing, Melbourne.

Crowley, M.A., C.C. Davey and A.L. Jorgensen (2006). 47th Annual assessment of shearwater breeding success on Montagu Island, 27-31 March 2006. Nature in Eurobodalla 20: 56-60.

Fullagar, P.J. (1989). The birds of Montagu Island, NSW. Nature in Eurobodalla 2: 27-35.

Fullagar, P.J. and P.C. Heyligers (1998). Montagu Island shearwater population survey March 1997. M I Partners Report No. 7 (iv + 10 pp).

Heyligers, P.C. and L.G. Adams (1989). Vascular flora of Montagu Island, NSW. Nature in Eurobodalla 2: 36-40.

Heyligers, P.C. and L.G. Adams (2004). Flora and vegetation of Montagu Island – past and present. Cunninghamia 8(3): 285-305.

Shaughnessy, P.D., S.V.Briggs, and R Constable (2001). Observations on seals at Montague Island, New South Wales. Australian Mammalogy 23: 1-7.