Shy in :

Population & Conservation Assessment.

Report for the

Wildlife and Marine 2007/08 field Conservation Section season Biodiversity Conservation Branch: DPIW

Introduction ...... 3

1 Methods ...... 4

Albatross Island...... 4 Fledgling winter trip ...... 4 Breeding effort trip...... 4 Hatching success trip ...... 5 Chick Banding trip ...... 5 Aerial flights...... 6 ...... 6 Island Visits ...... 6 Aerial photographs ...... 6 ...... 6 Island Visits ...... 6 Aerial photographs ...... 6 Results ...... 7

Geologger status ...... 7 Island...... 7 Breeding effort...... 7 Breeding effort in breeding success plots ...... 8 Hatching success ...... 11 Chick success ...... 12 Productivity and breeding success...... 13 ABBBS Data...... 14 Albino chicks ...... 15 Pedra Branca ...... 17 Mewstone ...... 18 Discussion...... 19

Factors influencing Chick success ...... 20 Pedra Branca ...... 21 Mewstone ...... 21 Recommendations: ...... 21 References...... 23

2 Introduction The , Thalassarche cauta, breeds exclusively on three small islands offshore ; Albatross Island in the northwest and Pedra Branca and the Mewstone to the south. The is classified as Vulnerable under Commonwealth Legislation, with an annual breeding population most recently estimated around 12500 pairs.

Interactions with , particularly long-lines, have been identified as a major threat facing albatross populations worldwide. In the 1980's and 1990's, significant numbers of Shy albatross were killed annually on tuna longlines operating in Tasmanian waters. The amount of longline effort around Tasmania has since been reduced, however this species is still at risk of being killed on longlines operating elsewhere. Juvenile are particularly vulnerable during the several years of absence after fledgling from their natal colony, during which time they may forage widely at sea. Band returns and satellite tracking have shown that some individuals traverse the high seas of the to forage off the coast of South Africa. It is this capacity for flight that means albatross may be killed during interactions with fishing industries operating far from their natal territory.

The potential for negative interactions with other fishing activities, particularly trawl fishing, is of growing concern. The Australian trawl operates within the foraging range of breeding shy albatrosses from all three populations, as well as overlapping extensively with the foraging range of non breeding (i.e. post breeding and juvenile) birds. The closely related white capped albatross, T. steadi, is killed in high numbers by trawl fisheries within the New Zealand EEZ.

A range of other anthropogenic influences potentially impact albatross populations, including competition for food with fisheries, augmentation of diet by fisheries discards, alteration of oceanic food webs due to human exploitation and global warming (summarised in Issues Paper).

Given the ongoing concerns about actual and potential threats, the Biodiversity Conservation Branch maintains a long-term monitoring program of Shy albatrosses on Albatross Island, since the early 1980’s. This program is designed to provide an ongoing review of the population and through the assessment of key demographic parameters including breeding success, adult survival and juvenile recruitment.

The Recovery Plan for Albatrosses and Giant petrel’s (DEH 2001) states that existing long term monitoring programs the measure demographic and breeding parameters of Shy albatrosses on Albatross Island, Pedra Branca and the Mewstone are maintained (Action D. 12.2). This program fulfils that requirement of the recovery plan.

3 Australia is signatory to the international Agreement for the Conservation of Albatrosses and Petrels (ACAP). It is a requirement of the Convention that member states support and facilitate monitoring and research into albatross population status and trends, and the information collected on Shy albatrosses by DPIW fulfils this requirement.

Methods

Albatross Island

Fledgling winter trip 20/7/2007 Rachael Alderman and Drew Lee visited Albatross Island on 20th July 2007 to collect bands from chicks banded in March/April 2007 that had failed to fledge.

Breeding effort trip 9/10/2007 – 17/10/2007 Personnel on this trip included Rachael Alderman, Drew Lee and Isabel Beasley from the Wildlife and Marine Conservation Section, assisted by Matt Larcombe from the Threatened Species Section (BCB). This trip was delayed by for two weeks by unfavourable weather.

The aims of the September/October trip are to obtain band resights for estimates of survival and to record breeding effort from various subsamples of the population. Figure 1 shows the location of the various colonies and breeding success plots on Albatross Island. One major task of this trip is to locate individual study birds in the south and north colonies (>400 individuals), mark their nest

Figure 1: Location of colonies and breeding success plots on location (using a combination of Albatross Island concrete nest markers and aerial maps), record nesting status and partner information. The resight information that is obtained underpins estimation of survival rates.

4 Another major aim of the September trip is to monitor trends in the breeding population (by recording the number of eggs laid). These estimates of breeding effort in turn allow the calculation of breeding parameters, i.e hatching, chick and overall breeding success. As the size of the Albatross Island population has increased over time, ground counts of eggs have been scaled back to reduce disturbance whilst maintaining research effort and accuracy. On ground estimates of breeding effort are typically conducted on population subsamples, including of the study nest birds in the North and South colonies, the West colony and the four breeding success plots (BSP) in Main and North colonies. Counts of eggs in the BSPs are used to estimate the proportion of unoccupied or ‘loafing’ birds present at the time the aerial photographs were taken. These ground truthing correction factors are applied to aerial counts to estimate the number of eggs laid in the larger colonies and on the whole island.

• 10/10/2007: Arrive/unpack – South Colony Study Nests • 11/10/2007: Breeding success Plots/Aerial photographs • 12/10/2007: Study nests • 13/10/2007: Study nests • 14/10/2007: Study nests • 15/10/2007: Study nests/West Colony Count • 16/10/2007: Study nests • 17/10/2007: Pack up/depart

Hatching success trip 6/12/2007 – 9/12/2007 Personnel on this trip were Rachael Alderman and Drew Lee (BCB). All study nests located and marked in September/October are revisited to measure hatching success. Hatching success is also recorded from breeding success plots and West colony. • 6/12/2007: Arrive – north colony study nests/west colony count – unpack • 7/12/2007: Breeding success plots • 8/12/2007: South colony study nests/weed removal • 9/12/2007: pack and depart

Chick Banding trip 27/03/2008 to 1/4/2008 Personnel on this trip were Rachael Alderman, Sue Robinson and Drew Lee from WMCS. All study nests, breeding success plots and west colony are revisited to record chicks success and overall breeding success. All chicks in the north and south colony are banded at this time. In addition this season, at the time of banding, a visual appraisal of pox and parasite levels of the study birds was

5 included in an effort to begin quantifying the prevalence and severity of the pox virus. Weights were obtained from 50 chicks in the North colony at the time of banding to provide an index of chick condition over the seasons. • 27/3/2008: Arrive – unpack, main colony breeding success plots • 28/3/2008: South colony study nests and non study chick banding • 29/3/2008: North colony study nests and breeding success plot banding • 30/3/2008: North colony breeding success plot and non study birds banding • 31/3/2008: North colony non study birds banding and west colony count • 01/4/2008: Pack and depart

Aerial flights

• 11/10/2007 Incubation aerial photographs – Sam Thalmann • 4/4/2008 Fledgling photographs – Rachael Alderman

Pedra Branca

Island Visits There are no scheduled visits to the island during incubation due to disturbance issues. The chick banding trip scheduled in April did not eventuate due to sustained unfavourable weather and transport logistics.

Aerial photographs

• 23/10/2007 Incubation aerial photographs – Rachael Alderman • 22/03/2008 Fledgling photographs – Rachael Alderman

Mewstone

Island Visits

• 5/9/2007 – an opportunistic visit whilst on to search for GLS loggers on breeding adults.

Aerial photographs

• 23/10/2007 – incubation aerial photographs were abandoned due to bad weather • 22/03/2008 – Fledgling photographs – Rachael Alderman

6 Results

Geologger status

Four geologgers were retrieved on Albatross Island in September 2007 from nesting adults and a further three in December. All loggers deployed on Albatross Island have now been successfully retrieved, (see Table 1). One logger was retrieved from a nesting adult on the Mewstone in September and another logger accounted for (i.e. the logger had broken off but the darvic band attachment was removed). Data downloaded from the retrieved loggers has undergone preliminary data analysis from BAS (Cambridge) in association with Dr. Richard Phillips. Further comprehensive analysis is pending.

Table 1. Status of GLS loggers deployed on Shy albatrosses Deployed Logger Logger lost* Remaining % loggers Retrieved accounted for Albatross Island 23 23 0 0 100% Mewstone 21 9 7 5 76% * resighted with the darvic band but the logger missing, indicating that loggers will not remain attached to the band indefinately. The darvic bands are removed.

Albatross Island

Breeding effort

As this visit was delayed by two weeks due to unfavourable weather, nests that failed soon after laying may have been missed and the total number of eggs laid underestimated. Failed nests were identified where possible by the presence of egg shell fragments. However in some cases failed nests may not be detected, e.g. if the egg was removed from the nest by gulls or if it was crushed into the ground or water. Breeding effort estimates from both ground counts and aerial methods are summarised in Table 2.

7 Table 2. Estimates of the number of eggs laid on Albatross Island Location Date Eggs empty failed breeding effort Main-Square BSP 11/10/2007 121 18 17 138 Main-South BSP 11/10/2007 202 24 36 238 Main-North BSP 11/10/2007 233 31 28 261 North Colony BSP 11/10/2007 329 66 20 349 West colony 16/10/2007 106 15 7 113 South colony 11/10/2007 574* Main colony 11/10/2007 3107* North colony 11/10/2007 1231* Total (sum of colony counts) 5025 * colony counts from aerial photos corrected by ground truth factor (0.75) BSP = breeding success plot

Breeding effort in breeding success plots The North and South

Breeding effort trends in BS plots BPS in the Main colony incorporate 400 Main Sth Main Nth edge and central Main Sq 350 North BS colony areas (See

300 Figure 1). They show similar 250 fluctuations in total 200 number of eggs N Eggs Laid N Eggs recorded against an 150 either stable or 100 slightly increasing

50 overall (Figure 2). 2000 2001 2002 2003 2004 2005 2006 2007 Statistical analyses Year of this and all trend Figure 2: trends in breeding effort in the breeding success plots on data using TRIM are Albatross Island, 2000/01 to 2007/08 pending. The Square BSP in Main colony differs from the North and South BSPs as it is situated in the centre of the colony, i.e. four fixed boundaries with no room for expansion on colony edges. This plot shows little of the fluctuation in breeding effort seen in the other two main colony BSPs and no sign of the increasing trend. The North colony BSP is similar to the Main colony North and South BSPs in structure, ie. it incorporates edge and central established colony areas and accordingly shows 8 similar patterns of an overall increase in breeding effort with annual fluctuations. These results suggest increases in the breeding population arise through expansion of breeding area rather than increases in nest density. The Square BSP does not show the pronounced reduction in breeding effort seen in the other plots in 2006. Due to its placement and delineation, the Square BSP likely represents older, more experienced breeding birds, whereas BSPs with expandable boundaries incorporate younger inexperienced breeders as well. It is possible that fluctuations in breeding effort are largely driven by the less experienced birds.

West colony The topography Trends in Breeding Effort West Colony of West Colony makes it less 180

160 suitable for aerial 140 counts than the 120 other colonies, 100 i.e. the nests are

N Eggs 80

60 often quite 40 widely spaced 20 amongst a 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 jumble of large year boulders. This

Figure 3: The number of eggs laid in West Colony 1995/96 - 2007/07 makes it difficult to obtain accurate aerial counts since many of the nests are obscured from the air by boulders. This also makes any correction factors for loafing birds unreliable. Given the small size of the colony (<160 nests), the ease of access to nests and the limited disturbance caused by researcher presence (i.e. nesting density is very low in comparison to the other three colonies), ground counts are the most accurate and efficient method of estimating breeding effort. Ground counts of West colony have been conducted every season since 1995. This season there were 113 eggs laid, the lowest figure since 2000 and the second lowest recorded since 1995, see Figure 3. There is no apparent trend in breeding numbers in this colony.

Individual colony (except West) and total island estimates of breeding effort use a combination of aerial methods and ground truthing. Aerial techniques have been in use since incubation 2004 with over 20 separate correction factors estimated in that time, incorporating a range of colonies and breeding success plots. Individual correction factors range from 57% to 88% of birds present in the photographs representing an actual breeding attempt. The substantial spatial and temporal

9 variation in correction factors means that how they are applied to aerial counts has a large influence on the number of breeding birds estimated. Assessing whether the most appropriate application is 1) a single figure i.e. the mean of every correction factor estimate from all areas and all seasons, 2) an annual estimate, i.e. the mean of correction factors from all areas in a given year or 3) separate area estimates, i.e. the mean of correction factors from all seasons for a given area, requires further data to quantify. Using method 1, the mean of all correction factors obtained to date is 0.75 (n = 20 SD = 0.1). Applying this to the aerial counts for North, South and Main colonies, plus the ground count of West colony, results in an estimated 5025 eggs laid, see Table 2. The estimate Albatross Island Breeding Effort of 5025 eggs laid in 6000 800

700 September 5000 600 2007 is very 4000 500 similar to the 3000 400 2006 estimate 300 2000 Island of 5013, which 200 Whole Island Egg Count Island Whole 1000 South Egg Count Colony South 100 was obtained

0 0 from a whole 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 island ground year count. Figure 4 Figure 4: Trends in breeding effort for South colony and entire Albatross shows the Island 1988/89 to 2007/08 The 2005 and 2007 estimates are aerial counts with change in a correction factor of 0.75 (see below). All other data are ground counts. Aerial photographs of Main colony in 2004 were poor quality so there are no breeding effort estimates of total population size that season. for the whole island since 1988, when the current program was initiated. Counts of all eggs laid in the south colony have been undertaken more consistently and are plotted for comparison. Both data-sets indicate the breeding population on Albatross Island has steadied after a prolonged gradual increase since annual monitoring began.

10 Hatching success Hatching success was recorded for study nests birds, west colony and the four breeding success plots in 2007/08, see Table 3.

Table 3 Hatching success on Albatross Island 2007/08 season Location Live dead Failed hatching egg total Success chicks chicks hatched % North study 84 2 9 4 18 90 66.7 South study 80 1 3 8 7 89 76.1 Main-South BS 129 7 29 0 21 136 57.1 Main-Square BS 90 1 11 0 11 91 65.9 Main-North BS 176 7 22 0 22 183 70.1 North BS 266 3 16 0 32 269 77.1 West colony 67 6 18 1 14 74 64.6 Main colony* 64.4 North colony† 71.9 Island Mean 69.0 *Main colony hatching success = mean of BS plots North Colony hatching success = mean of study nests and BS plots

Hatching success trends in hatching success on Albatross Island values were higher 100 for all colonies this season than in 2006 80 but there is no apparent overall 60 trend in any of the colonies (Figure 5). success (%) 40 All colonies exhibit similar increasing or 20 South Main decreasing trends North West relative to the 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 previous one (with season the exception of Figure 5: Hatching success on Albatross Island 1990/91 to 2007/08 west colony in 2001). There are however marked differences between the colony estimates (i.e. up to 40%). In general, main and north colonies show higher hatching success than south or west colonies. This 11 season, south colony hatching success (derived from Study birds) was 76% and unusually higher than all other colonies.

Chick success

Historical monitoring data (1988-2004) was crosschecked and reliable estimates of chick success extracted to examine trends in this parameter. There is significant variation in the proportion of chicks surviving, both spatially and temporally (See Figure 6). Estimates of chick success range from 22% to 86%. trends in chick success on Albatross Island Compared to 100 South (SN) hatching success West Main (BSP) (Figure 5), the 80 North (SN and BSP) magnitude of change in chick 60 success from one season to the next is success (%) 40 much greater and there is less 20 consistency in trends between the

0 colonies. 1990 1992 1994 1996 1998 2000 2002 2004 2006 Season Furthermore the observed trends in Figure 6: trends in chick success on Albatross Island 1990/91 to 2007/08 hatching success are not always reflected in chick success. This suggests the factors influencing hatching success are island wide, whereas there are colony specific factors influencing chick success. One influencing factor may be the incidence of the pox virus (Woods 2004). This year, methods to quantify the prevalence and magnitude of the virus were implemented into the annual field program. Scabby growths on legs and feet are an obvious physical manifestations of the pox virus and the severity and incidence was recorded for north and south study birds at the time of banding. More data is required to detect trends, however the results (Table 4) are consistent with the perception that the pox virus is more extensive in the South Colony.

12 Table 4: Percentage of study birds in each pox prevalence category Pox Level South Study Birds% N North Study Birds% N None (0) 33 13 49 24 Low Level (1) 40 16 35 35 Heavy (2) 20 8 12 12 Extreme (3) 8 3 4 4

Weights were obtained from North colony chicks whilst banding in March 2007 and in March 2008 to provide an index of chick condition. The mean weight in 2008 (4.58kg) was slightly but significantly lower than in 2007 (4.90kg) (Students T test, T=1.99, P=0.03). This seems counter intuitive, i.e. relative to 2006/07, north colony chick success was slightly higher in 2007/08 but the mean weight of chicks was lower. More data is required and perhaps with broader spatial sampling to understand the relative importance of factors influencing chick survival.

Productivity and breeding success Breeding success was estimated for the north and south colony study nests, west colony and the four breeding success plots, see Table 5.

Table 5: Breeding success estimates for Albatross Island Location N Eggs N Chicks Breeding Success % Main South BS 238 88 37 Main Square BS 138 66 48 Main Nortb BS 261 87 33 North Colony BS 349 171 49 West Colony 113 34 30 South Study Nests 135 50 37 North Study Nests 117 47 40 Island Mean 38

13 Figure 7 shows the trends in breeding success and chick productivity since 1980. The two parameters are closely linked. The number of chicks on Albatross Island shows a gradually increasing trend from 1980 to 2001, with a rapid decline for three consecutive seasons from 2004/05. The total estimate of 2092 chicks counted from the aerial photographs in April 2008 halts the downward trend although it remain a long way from the peak recorded in 2003/04. Island wide, an estimated 38% of eggs laid chick productivity on Albatross Island survived to pre- 3500 60 fledging chicks at

3000 50 the time of the

2500 aerial census in 40 2007/08. Similar 2000 30 to the chick 1500 productivity, this 20 Pre-fledging chicks 1000 estimate is a

10 500 Chicks Mean Island Breeding Success (%) significant Breeding Success increase from 0 0 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 the 2006/07 Year estimate of 26%.

Figure 7: Chick production and breeding success on Albatross Island

ABBBS Data

A total of 804 chicks were banded in the North and South colonies of Albatross Island this year. All data has been submitted to ABBBS. Thirteen band returns have been obtained away from the breeding colonies during the 2007-08 season (Table 6)

14 Table 6: Bands recoveries from Shy Albatrosses 2007-08 Band Colony Age Years Where Found 13164300 Mewstone 14.8 Cox Bight Tas 13164407 Mewstone 14.9 Victorian Coast 13204761 Albatross Island 6.25 Phillip Island 13209049 Albatross Island 5.9 Victorian Coast 13229839 Albatross Island 0.2 Sth Australian Coast 13229985 Albatross Island 0.2 Victorian Coast 13230315 Albatross Island 0.1 13232759 Albatross Island 0.2 Victorian Coast 28001978 Albatross Island 26.25 Phillip Island 28002181 Albatross Island 24.3 King Island 28005653 Albatross Island 20.7 St Helens Tas 28008553 Albatross Island 21.8 Sth Australian Coast 28011179 Albatross Island 20.2 Victorian Coast

Albino chicks

One complete albino (Figure 8 Top) and one leucistic chick (Figure 8 Bottom) were observed in the North colony at the time of banding. There are typically one or two albino chicks recorded each year, although this is the first record of a leucistic chick. No albino adults have ever been resighted on the island and given the typically poor condition at time of banding, it is assumed that they do not survive long after fledging. Albinism is thought to impair vision, which may lead to reduced foraging success. Albino birds are also thought to have brittle wing and tail feathers, which may also impair flight.

Figure 8: Albino and Leucistic chick - Albatross Island 15 General observations. • A pair of Cape Barren geese with chick were present on the northern edge of Main colony in September. The chick was not seen in either subsequent visit, however adults were present in the same area in March. • A small patch of feral grass Catapodium marinum (Stiff sandgrass) was discovered on the north west of the island in September. This is a common weed on King Island and could have easily been introduced by wind, birds or humans. All material, including the 1-2 inches of substrate was dug up and removed from the island in December. Close monitoring of this site is required to ensure there is no re-establishment from seed bank. • In December, an adult bird in the southern main colony was encountered with fishing handline tangled round legs and feet. This bird was not on a nest and was immediately captured and the hand line cut free. Given the location and circumstances of the bird, there was insufficient time to take a photograph. • A juvenile from the BBR was resighted. • No nesting from the sea eagles. They were not present in usual location opposite camp cave in September, but were observed flying around the southern edge of the island. No nest was located. • On arrival in March, the landing rock was covered in crested terns, between 50-100. They moved on when we landed, but remained in the area for the duration of the trip. • A seismic vessel surveying waters in western passed close by Albatross Island on the evening of the 29th March. We observed that the vessel was extremely brightly illuminated and noted the potential for the lighting to result in bird strike and significant mortality of prions and .

16 Pedra Branca

The aerial photographs of Pedra Branca in both incubation and pre-fledging were of high quality and enabled accurate counts (e.g. Figure 9).

Figure 9: Example of aerial photographs taken on Pedra Branca during incubation

A total of 216 adult birds were counted in incubation, which continues the decreasing trend in adult numbers observed since 2004 (Figure 10). Note that the proportion of unoccupied adults in the photographs is not estimated as there are no correction factors for Pedra Branca and so the number of albatross actually breeding cannot be estimated. It is assumed that trends in the total number of birds counted in the photograph reflect trends in breeding effort.

There were 35 chicks counted in the aerial photographs taken in March 2008, which is slightly more than the previous season. As there was no visit in April, these counts cannot be validated, however there are historical data to determine accuracy rate for aerial chick estimates on Pedra

17 Branca. It is likely that this purely aerial count slightly overestimates the number of chicks that survive to fledging, since dead chicks are not easily distinguished from aerial photographs if they are recently deceased and nor are adult birds reliably identified.

Regardless, both Population trends of Shy Albatross on Pedra Branca adult and chick numbers show a chicks adults rapidly decreasing 320 adults unverified trend and the population appears 240 at imminent risk of extinction.

160

80

0 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year

Figure 10: Population trends on Pedra Branca 1992/93 to 2007/08

Mewstone The flight planned for October to photograph incubating birds in the five breeding success plots was cancelled due to bad weather and so there is no estimation of adult birds in the five plots for 2007. The value of relying on aerial photographs to estimate breeding effort in the Mewstone plots is questioned. There are no ground truth data to correct the number of birds counted in the photographs against the actual number of breeding attempts. Nor is there any quantification of the birds on the ground obscured from the air by rocks and boulders.

The photographs of the chicks were of good quality but have yet to be counted. There is limited on- ground data to quantify the number of chicks in the plots that are not visible from the air. Although of unknown accuracy, the chick counts in the five plots may provide an index of chick productivity on the Mewstone.

18 In April 2005, an attempt was made to photograph the entire island to estimate the total number of chicks. Hundreds of man-hours over the subsequent two years have been spent identifying, sorting, grading and counting more than 500 aerial photographs.

A preliminary estimate at this time is of 4345 chicks on the Mewstone. This figure is likely to be modified with further double checking of counts and count error estimation. What is almost certain is that this number underestimates the actual number of chicks on the island at the time of the photographs. Although many hundreds of photographs were taken, some areas of the island were not represented with an image of sufficient quality to count birds. Additionally, the unknown proportion of chicks that are obscured from the air (as described above) results in an underestimation.

The total breeding population of the Mewstone can be extrapolated from a chick count using breeding success estimates. Reliable estimates of breeding success are lacking from the Mewstone. If the average breeding success for Albatross Island (38%) is instead applied to the Mewstone chick count, the estimate breeding population exceeds 11000 pairs. A higher breeding success estimates results in a smaller breeding population. For example, 50% breeding success, which has been recorded in some areas of Albatross Island, would result in an estimated breeding population of around 9000 pairs. Based on observation, a breeding success seems unlikely to be this high overall on the Mewstone.

Discussion With the inclusion of the first repeatable and reliable population estimate for the Mewstone, this season provides the first estimate for the total Shy Albatross breeding population of: 14250-16250. Population trends are known for Albatross Island and for Pedra Branca but not for the Mewstone. Since that colony represents around 60% of the total population, knowing the status of the Mewstone is important for assessing the global population status. By committing to the Agreement for the Conservation of Albatrosses and Petrels (ACAP), Australia acknowledges the importance facilitating and support research into the status and trends of albatross and petrel populations. As Shy albatross breed exclusively under Tasmanian Jurisdiction, the information collected and disseminated under the DPIW research program is of global significance (See Attached Shy albatross species Assessment).

Albatross Island The Albatross Island population was reduced to as little as 200 breeding pairs in the late 1800s by feather and egg collectors (Ashworth and Le Souëf 1895; Le Souëf 1895). The pre-exploitation population level may is thought to have been between 14 000 and 20 000 breeding pairs (DPIW

19 unpublished). This is a coarse estimate based on previous colony extent mapped from old guano deposits combined with nest density estimates. Following the cessation of direct exploitation, the population showed a steady recovery over the next 100 years (Johnstone, Milledge et al. 1975; Hamilton 2003). The most recent population data reported here suggests the rate of increase has slowed, that the population is currently stable and that fluctuations in the number of chicks produced annually are largely driven by variation in breeding success. The current population seems to have largely stabilised at as little as 1/3 the estimated size of the historical population. This could be due to a range of factors; including • Reduced adult survival or juvenile recruitment rates, • an incorrect estimate of pre-exploitation levels • a reduced carrying capacity (K) for the current population compared to the historical one, potentially driven by changes in food availability and/or competition.

More comprehensive analyses of population and demographic data are ongoing and these further our understanding of the population processes operating on Albatross Island. One possibility that requires investigation is the potential impact of trawl fishing on Shy albatross survival. Although there is limited longline fishing effort and fatal interactions are thought to be minimal, there is increasing global concern about the impact of trawl fishing on albatross, e.g. (Baird 2008). There is extensive spatial and temporal overlap between both adult and juvenile Shy albatrosses from Albatross Island with the trawl fishery in South East Australian waters and the potential for there to be significant impact on survival. It is important that the interactions between seabirds and the trawl fishery operating in the AFZ are investigated to quantify the potential risk.

Factors influencing Chick success Productivity is largely determined by breeding success, and chick success appears more temporally and spatially variable than hatching success. Preliminary investigation into two of the more obvious likely factors influencing chick success are; chick condition (using weight as an index of food availability) and the prevalence and severity of the pox virus. Preliminary investigations into the epidemiology of the virus have been undertaken (Woods 2004) but it remains poorly understood. In Laysan Albatross breeding in Hawaii, the prevalence of Avian Pox was related to rainfall (Young and VanderWerf 2008), however mosquitos are the main vector for that population whereas it seems fleas and/or ticks are thought to be more important on Albatross Island. Therefore, the climatic variation may impact the disease on Albatross Island in a different way to the Hawaiian Islands.

20 Pedra Branca The dramatic decline of the Shy albatross population on Pedra Branca appears to be influenced by an increase in gannets. Gannets are known to be increasing throughout the Australasian region. In 1995, there were an estimated 3300 pairs of gannets on Pedra Branca (Bunce, Norman et al. 2002). It was reported in that paper that there was limited space for the gannet population to expand into, implying that further increases were unlikely. The series of aerial photographs taken of Shy albatrosses during incubation since 2004 suggest this is incorrect. Although no total counts of gannet numbers can be obtained from these photographs, they clearly show a steady encroaching of gannets into the stronghold albatross nesting areas, where previously they were not present. Given the size differences between the two species, it seems more plausible that gannets are causing a reduction in chick success, which will ultimately lead to a reduction in the breeding population, rather than outcompeting breeding adults.

Mewstone The Mewstone population represents the largest of the Shy albatross populations and it is also the most enigmatic. The remote location and largely inaccessible nature of this island have made estimating the population status problematic. The preliminary estimate reported here of somewhere between 9000 and 11000 breeding pairs represents the first attempt to estimate of the entire population since 1996. In that season, Nigel Brothers made a visual estimate of the number of nests and suggested a breeding population of 7360 in 1996 (Unpublished DPIW – Brothers). This estimate is of unknown accuracy. Ground counts are known to underestimate actual population size, particularly on complex terrain (Roberston, Moreno et al. 2008) and a significant proportion of the nesting areas on the Mewstone cannot be accessed. As the 1996 estimate cannot be repeated and is, given the terrain and methods used, likely to be unreliable, that estimate cannot be compared with that presented here.

Recommendations:

General • Investigate the incidence of interactions between Shy albatrosses and trawl fisheries within the AFZ.

Albatross Island • Consider adding a breeding success/ground truth area to the South Colony to obtain correction factors specific to that colony. • Update estimates of juvenile and adult survival rates • Run all breeding effort and chick production trend data through TRIM for statistical analysis.

21 Mewstone • Continue to refine aerial methods with ground truthing • Revisit for GLS logger retrieval • Establish if the pox virus is present in birds on the Mewstone

Pedra Branca • Obtain an up to date estimate of the number of gannets on the island. • Obtain baseline pox virus data • Obtain reliable estimates for Shy albatross breeding effort, hatching success and chick success to investigate mechanism for observed population decline (see proposed research plan below)

Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun GANNETS BREEDING PHENOLOGY EGG LAY HATCH FLEDGE SHY ALBATROSS PHENOLOGY

CURRENT PEDRA BRANCA FIELD SEASON FLIGHTS VISITS PROPOSED PEDRA BRANCA FIELD SEASON FLIGHTS VISITS Dark shading in phenology time series indicates peak times for activity.

Depending upon resource and disturbance considerations: 1) A ground count of eggs in early October to estimate breeding effort and provide ground truth for aerial photographs. 2) Hatching success could be reliably determined from a ground count in late December/Early January or estimated from a series of aerial photographs in December-February monitoring the presence of adult birds/unattended chicks on nests known to have eggs (marked on the September aerial photographs). 3) Chick success and productivity assessed as normal with a combination of aerial photographs and an island visit in March/April. 22 References

Ashworth, H. P. C. and W. H. D. Le Souëf (1895). "Albatross Island and the Hunter Group." Victorian Naturalist 11: 134-144. Baird, S. J. (2008). Net Captures of seabirds during trawl fishing operations in New Zealand waters New Zealand Fisheries Assessment Report, NIWA. Bunce, A., F. I. Norman, et al. (2002). "Long-term trends in the (Morus serrator) population in Australia: the effect of climate change and commercial fisheries." Marine Biology 141(2): 263-269. Hamilton, S. (2003). Shy albatrosses in Australia: Population and Conservation Assessment, Nature Conservation Branch D.P.I.W.E. Johnstone, G. W., D. Milledge, et al. (1975). "The White-capped albatross of Albatross Island: numbers and breeding behaviour." Emu 75: 1-11. Le Souëf, W. H. D. (1895). "Notes on birds found nesting on Albatross Island in Bass Strait Australia." Ibis 7(1): 413-423. Roberston, G., C. A. Moreno, et al. (2008). "Comparison of census methods for black-browed albatrosses breeding at the Ildefonso Archipelago, Chile." Polar Biology 31: 153-162. Woods, R. (2004). Results of a preliminary disease survey in Shy albatross (Thalassarche cauta Gould 1841) chicks at Albatross Island, Bass Strait, Tasmania. Australian Association of Veterinary Conservation Biologists, Canberra. Young, L. C. and E. A. VanderWerf (2008). "Prevalence of avian pox virus and effect on the fledging success of Laysan Albatross." Journal of Field Ornithology 79(1): 93-98.

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