Commonwealth of Australia

Environment Protection and Biodiversity Conservation Act 1999

Environment Protection and Biodiversity Conservation (Recovery Plan—Australian Fairy Tern (Sternula nereis nereis)) Instrument 2022

I, Sussan Ley, Minister for the Environment, under section 269A(3) of the Environment Protection and Biodiversity Conservation Act 1999 (Cth), hereby jointly make a recovery plan with the Western Australia Minister for Environment, the Hon Reece Whitby MLA, the South Australia Minister for Environment and Water, the Hon David Speirs MP and Victoria Minister for Energy, Environment and Climate Change, the Hon Lily D’Ambrosio MP, for the listed threatened species specified below, entitled “National Recovery Plan for the Australian Fairy Tern”.

The recovery plan will come into force on the day after the plan is registered on the Federal Register of Legislation.

Dated this 28 day of March 2022

Sussan Ley

Sussan Ley

Minister for the Environment (Commonwealth)

Dated this 8 day of March 2022

Reece Whitby

Reece Whitby

Minister for Environment (Western Australia)

Dated this 16 day of April 2021

David Speirs

David Speirs

Minister for Environment and Water (South Australia)

Dated this 31st day of December 2021

Lily D’Ambrosio

Lily D’Ambrosio

Minister for Energy, Environment and Climate Change (Victoria)

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ISBN 978-1-76003-332-3

This report should be attributed as ‘National Recovery Plan for the Australian Fairy Tern (Sternula nereis nereis), Commonwealth of Australia 2020’.

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Images credit

Cover page: Adult Australian Fairy Tern (Sternula nereis nereis) over Rottnest Island, Western Australia © Georgina Steytler

All other images: © Claire Greenwell

Contents

Summary 1

1          Introduction 3

1.1      Conservation status 3

1.2      Taxonomy 4

1.3      Species description 4

1.4      Species distribution in Australia 5

1.5      Population trends 7

1.6      Ecology 8

1.7      Habitat critical to the survival of the Australian Fairy Tern 10

2          Threats 12

2.1      Historical causes of decline 12

2.2      Current threatening processes 12

2.2.1  Habitat degradation and loss of breeding habitat 13

2.2.2  Disturbance 14

2.2.3  Invasive species 14

2.2.4  Native wildlife 15

2.2.5  Climate variability and change 15

2.2.6  Water management and increased salinity 15

2.2.7  Pollution 16

2.2.8  Hybridisation 16

2.3      Threat prioritisation 17

3          Populations under particular pressure 19

3.1      Local conservation strategies 19

4          Recovery plan vision, objectives, and strategies 21

5          Actions to achieve the specific objectives 22

6          Duration and cost of the recovery process 31

7          Effects on other native species and biodiversity benefits 32

8          Social and economic considerations 33

9          Affected interests 34

10       Consultation 37

11       Organisations/persons involved in evaluating the

performance of the plan 38

12       References 40

Contents

iv National Recovery Plan for the Australian Fairy Tern (Sternula nereis nereis)

Summary

Australian Fairy Tern (Sternula nereis nereis)

Family: Laridae

Current status of taxon:

•       Environment Protection and Biodiversity Conservation Act 1999 (Cwlth): Vulnerable

•       Threatened Species Protection Act 1995 (Tas): Vulnerable

•       Flora and Fauna Guarantee Act 1988 (Vic): Critically Endangered

•       National Parks and Wildlife Act 1972 (SA): Endangered

•       Biodiversity Conservation Act 2016 (WA): Vulnerable

Distribution and habitat:

Australian Fairy Terns occur along the southern Australian coast from south of the Dampier archipelago Western Australia east to Botany Bay, New South Wales including Tasmania. The Great Australian Bight forms a gap in distribution between western and eastern subpopulations (Higgins and Davies 1996), and there are now substantial gaps amongst breeding colonies in eastern Australia, especially around the Victorian

coastline (Garnett et al. 2011). Australian Fairy Terns use a variety of habitats including offshore, estuarine, lacustrine (lake) islands, wetlands, beaches and sand spits

(TSSC 2011).

Recovery plan vision, objective, and strategies:

Long-term vision

The Australian Fairy Tern population has increased in size to such an extent that the species no longer qualifies for listing as threatened under any of the Environment Protection and Biodiversity Conservation Act 1999 listing criteria.

Recovery plan objective:

By 2030, sustain a positive population trend (compared to 2020 baseline counts) in the number of mature individuals of the Australian Fairy Tern in both the eastern and western populations. This will be achieved by implementing the actions set out in this

Recovery Plan that minimise threats while protecting the species’ habitat throughout its range, adequately monitoring the species, generating new knowledge to guide recovery and increasing public awareness.

Summary

Strategies to achieve objectives

1     Manage and protect known Australian Fairy Tern breeding populations at the landscape scale

2     Develop and apply techniques to measure changes in population trend(s) in order to measure the efficacy of recovery actions

3     Reduce, or eliminate threats at breeding, non-breeding and foraging sites

4     Undertake research and monitoring to improve understanding of breeding,

non-breeding and foraging ecology in order to better target management actions and habitat restoration

5     Engage community stakeholders in Australian Fairy Tern conservation

6     Coordinate, review and report on recovery progress

Criteria for success:

This recovery plan will be deemed successful if, by 2030, all of the following have been achieved:

•      The Australian Fairy Tern population has increased from 2020 baseline counts, as a result of recovery actions.

•      Understanding of the species’ ecology has increased, in particular knowledge of population size, breeding biology, movement patterns, food availability and foraging efficiency relative to colony success, habitat use including the interaction between marine and terrestrial habitat features, post-breeding dispersal and survival rates.

•      There is increased participation by key Australian stakeholders and the public in recovery efforts and monitoring.

Recovery team:

Recovery teams provide advice and assist in coordinating actions described in recovery plans. They include representatives from organisations with a direct interest in the recovery of the species, including those involved in funding and those participating in actions that support the recovery of the species. The national Australian Fairy Tern Recovery Team has the responsibility of providing advice, coordinating and directing the implementation of the recovery actions outlined in this recovery plan. The membership of the national Recovery Team includes individuals from relevant government agencies, non-government organisations and expertise from independent researchers and community groups.

Chapter 1

Introduction

This document constitutes the National Recovery Plan for the Australian Fairy Tern.

The plan considers the conservation requirements of the species across its range and identifies the actions to be taken to ensure the long-term viability of the species, and the parties that will undertake those actions. The Recovery Plan is the first national plan to be developed for the Australian Fairy Tern.

The Australian Fairy Tern was listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) on 3 March 2011. At the time of listing there were fewer than 9,000 mature individuals remaining and the total

population had undergone a substantial decrease of approximately 24 per cent over the past three generations, or 33 years (TSSC 2011). This decrease was expected to continue at a substantial rate over the next three generations, as there was no evidence that the threats affecting this species were abating (TSSC 2011). In 2020, the population was estimated to be 7,450 (range 6,800 – 8,100) mature individuals and was undergoing a continuing decrease, particularly in eastern Australia (Greenwell et al. 2021). There has been no change in the population trajectory since 2011 and the species continues to meet the Vulnerable category (Greenwell et al. 2021).

The accompanying Species Profile and Threats Database (SPRAT) pages provide background information on the biology, population status and threats to the Australian Fairy Tern. The SPRAT pages are available from: http://www.environment.gov.au/ cgibin/sprat/public/sprat.pl.

1.1            Conservation status

The Australian Fairy Tern is listed as threatened under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), and under State legislation (Table 1) in all parts of its range, except New South Wales. This species was included in the Vulnerable category under the EPBC Act in 2011 due to decreases in the number of mature individuals over much of its breeding range. Predation by introduced species, disturbance and inappropriate water level management are thought to have contributed most to this decrease.

TABLE 1 National and state conservation status of the Australian Fairy Tern

1.2            Taxonomy

The Australian Fairy Tern is conventionally accepted as Sternula nereis nereis (AFD 2019). It has been suggested that there are two subspecies on mainland Australia,

S. n. nereis in the south-east and S. n. hornii in the south-west, although key authorities only recognise S. n. nereis in Australia (Baling and Brunton 2005; Christidis and Boles 2008; Garnett et al. 2011; AFD 2019). Genetic differences were detected between Australian Fairy Terns in Western Australia and south-eastern Australia, however, these were not sufficient to merit treatment as separate subspecies (Dunlop 2018). The highest genetic diversity was found in the largest population in Western Australia (Baling and Brunton 2005), suggesting that this region was the source for the smaller breeding groups found in south-eastern Australia.

The distribution of the Fairy Tern (Sternula nereis) is limited to Australasia, comprising Australia, New Zealand and New Caledonia (Hansen 2006; Dunlop 2018).

Three subspecies have been identified based on phenotypic, genotypic and geographic differences. The New Zealand Fairy Tern (S. n. davise) is listed as Nationally Critical under the New Zealand Threat Classification System (Hitchmough et al. 2005; Hansen 2006).

The New Caledonian Fairy Tern (S. n. exsul) has approximately 200–400 breeding pairs (Barre et al. 2011), and has recently been recorded in the Swain Reefs, southern Great Barrier Reef, and islands in the Coral Sea Territory, suggesting regular movements of over 1,200 km (Carter and Mustoe 2007; Garnett et al. 2011). The low genetic diversity in the satellite populations in New Zealand and New Caledonia probably reflect the small number of founders (Dunlop 2018).

1.3            Species description

A small piscivorous (fish-eating) bird, the Australian Fairy Tern is approximately 22–27 cm in length, 70 g in mass and has a wingspan of 44–53 cm (Higgins and Davies 1996). The Australian Fairy Tern is bulky and round bodied (Simpson and Day 2004).

The species is very similar to Little Tern (S. albifrons) which in breeding plumage can be distinguished from the Australian Fairy Tern by the yellow, black tipped bill and black line through the eye reaching the bill. Little Terns are overall slimmer than

Australian Fairy Terns with darker upperparts and outer primaries (Slater et al. 2009; Menkhorst et al. 2017).

The breeding plumage of both sexes is pale grey-white, with a black crown, nape, ear coverts and patch in front of the eyes (square to round in shape). The forehead is white and the bill is orange-yellow (Higgins and Davies 1996). Legs are dull yellow and the iris is dark brown (Lindsey 1986).

There is also little sexual dimorphism in non-breeding plumage, with a black bill and a more mottled appearance to the crown (Higgins and Davies 1996). The outer primary feathers are also less contrasting with no dark shoulder bar (Simpson and Day 2004).

Immature birds have blackish legs and bills (Lindsey 1986). The crown is streaked dusky and buff with a dark ear patch. The outer wing is dark greyish and the inner wing is pale grey and white (Simpson and Day 2004).

1.4            Species distribution in Australia

The Australian Fairy Tern occurs in coastal southern Australia from the Montebello Islands of the Pilbara, Western Australia east to Botany Bay, New South Wales including Tasmania (Figure 1). The Great Australian Bight forms a gap in distribution between western and eastern populations (Higgins and Davies 1996). There are now a reduced number of nesting colonies in eastern Australia, especially around the Victorian coastline. The species has been recorded in Queensland but is considered to be a vagrant, an occasional visitor or more likely, New Caledonian Fairy Tern individuals.

In Tasmania, Australian Fairy Terns have suffered dramatic population declines.

Both Little and Australian Fairy Tern often nest together and some colonies are well documented. Eight colonies are known to be present in the Glamorgan-Spring Bay and Sorell Municipalities in south-east Tasmania (Blakney 2018). There are four known Key Biodiversity Areas in Tasmania based in part on their value to Australian Fairy Terns, primarily through supporting their breeding locations: Orford, Marion Bay, St Helens and Eastern Flinders Island (Bass Strait). In 2020, the Orford Bird Sanctuary had one of the best breeding seasons in many years with at least 40 adults and 27 chicks recorded between January and February (E. McDonald and P. Geard pers. comm). Maintaining, and if possible, increasing the number and size of these colonies in Tasmania will be crucial to recovering this species in south-east Australia.

Within Western Australia, there appear to be two subpopulations (Dunlop 2018). One is sedentary and based along the Pilbara and upper Gascoyne coasts from Exmouth Gulf to the Dampier Archipelago, including Barrow Island and the Montebello and Lowendal Archipelagos. These Australian Fairy Terns nest from late July to late September (Johnstone and Storr 1998, Dunlop 2018). A second, migratory subpopulation disperses south along the coastline from Shark Bay (Burbidge and Fuller 2000) to breed between the Houtman Abrolhos Islands to the Recherche Archipelago between September

and May, with active breeding flocks appearing at various locations between October and February (Johnstone and Storr 1998). At present it is not clear what controls the recruitment of individuals to these over-lapping subpopulations (Dunlop 2018). It is also currently not known at what scale local breeding groups (which probably establish colonies at a number of sites) represent conservation management units within the migratory subpopulation (Dunlop 2018).

Biologically Important Areas for this species occur in Australian Marine Parks, particularly in the South-west and North-west Marine Parks Networks. Under statutory management plans, Australian Marine Parks are managed for the protection and conservation of biodiversity and other natural, cultural and heritage values of marine parks, including protected species. More information about Australian Marine Parks can be found here.

FIGURE 1 Modelled distribution of the Australian Fairy Tern

1.5            Population trends

The population of Australian Fairy Terns is about 7,450 (range 6,800–8,100) mature individuals (Greenwell et al. 2021). The largest population of 5,000–6,000 in Western Australia is believed to be stable but there is no reliable historical data. In eastern Australia there have been rapid decreases. State based estimates include 900–1,150 in South Australia (DENR 2012; Cooper 2015; Stephens and Lamanna 2019; D. Paton unpublished), 100–120 pairs in Tasmania (2019/20, E.J. Woehler pers. comm. 2020), 100–150 in Victoria (Adams et al. 2019) and fewer than 50 in New South Wales (South Coast Shorebird Recovery Program 2017; Greenwell et al. 2021).

In South Australia, a survey of 1500 km of coastline in 2011/12 found a minimum of 944 birds at 19 sites (DENR 2012). Numbers in the South Lagoon of the Coorong, Lakes Alexandrina and Albert Wetland Ramsar site (the Coorong) have decreased from 1,330 individuals in 1985 to 150–300 in 2000–2007, an 82 per cent decline (Paton and

Rogers 2009). Only 357 individuals were counted during the annual census of waterbirds in the Coorong in January 2018. This result is less than in January 2015 and 2016 and

is only a little over half of the birds that were using the Coorong in the early 2000s (Paton and Paton 2018). Australian Fairy Tern numbers have continued to decrease in the Coorong over the last five years from 300–350 adult birds to 315 individuals in

January 2019 (Paton et al. 2019). Elsewhere in South Australia, the species disappeared from the Fleurieu Peninsula in the late 1970s and around Kangaroo Island in the early 1990s, however, small numbers are now breeding again around Kangaroo Island

(D. Paton, pers. comm. 2020). Breeding populations in Gulf St Vincent, Spencer Gulf and near Beachport are very small with low breeding success (Garnett et al. 2011).

One island in particular in Gulf St Vincent just 20 km north of Adelaide, Bird Island, has been monitored since 2001, and more intensively since 2015 with weekly visits over the 2018–19 and 2019–20 seasons (Stephens and Lamanna 2019). Bird Island had between 10 and 35 breeding pairs in early 2000s, approximately 60–80 pairs between 2015–2018 and over the 2018–19 season 50–60 pairs (Stephens and Lamanna 2019).

In Victoria, the number of breeding pairs at French Island in Western Port Ramsar site decreased from a peak of 108 in 1993 to an average of 21 for the decade 1996–2005 (Garnett et al. 2001). Historically, colonies of over 50 breeding pairs were observed within Western Port and Port Phillip Bay Ramsar sites but numbers began to decrease in the late 1980s (Adams et al. 2019). There are currently few records documenting successful breeding attempts over the last decade within the two bays and it is thought that breeding success is poor (Adams et al. 2019). Approximately 54 adults comprising three colonies were observed within Western Port and Port Phillip Bay Ramsar sites during the 2016–17 breeding season. Only one breeding colony of 30–40 adults was observed during the 2017–18 breeding season while no breeding colonies were detected during the 2018–19 breeding season (Adams et al. 2019). In Victoria, no successful breeding has occurred in Western Port and Port Phillip Bay Ramsar sites in either the 2017–18 or 2018–19 breeding season (Adams et al. 2019). Gippsland Lakes Ramsar site continues to host breeding Australian Fairy Terns. From 2015–2018,

114 Australian Fairy Terns chicks fledged across the Gippsland Lakes Ramsar site. This was a noteworthy increase in recruitment post sand island rehabilitation. Prior to this, numbers of fledglings of both Australian Fairy and Little Tern species for many years had been recorded in single figures only (DELWP, unpublished). In 2018–19,

an estimated 25 Australian Fairy Terns chicks fledged from only one breeding site. The 2019/20 season did not produce any fledglings despite multiple nesting attempts (Sullivan et al, unpublished report).

In New Zealand, subspecies davisae declined to three pairs in 1983 but due to intensive conservation efforts increased to 25–30 birds and 8–10 pairs over four sites in 1998 (Hansen 2006). In 2006 the population had increased to 30–40 individuals and

10 pairs (Parrish and Honnor 1997, Taylor 2000). By 2011, this had increased again to 40–45 individuals and 10 pairs (P-J. Pridham in litt. 2011). As of 2019, the current breeding population is six pairs.

In New Caledonia, subspecies exsul numbers 200–400 pairs, but was formerly much more abundant (Barre et al. 2012; BirdLife International 2019). One small population in the Southern Lagoon of New Caledonia may be increasing (Baling et al. 2009).

1.6            Ecology

 Social behaviour

As with all other terns (Cabot and Nisbet 2013), Australian Fairy Terns are gregarious, gathering together at roost sites both during and outside the breeding season (Dunlop 2018). In Western Australia, night roosts are generally located on open shoreline features such as sandspits, away from vegetation cover and predators (Dunlop 2018). Some are only occupied during the arrival period whilst others are occupied for most of the breeding season. These roosts may contain birds at a range

of ages with the composition changing as the season progresses (Dunlop 2018). Night roosts may include pre- and post-breeding experienced adults, individuals entering their first breeding season, non-breeding individuals in their first summer, and fledglings (Dunlop 2018; J.N. Dunlop pers. obs.).

The social behaviour associated with colony site selection and establishment has not been investigated in Australian Fairy Terns, probably because it is hard to predict when and where it will occur (Dunlop 2018). In other terns that do not have inter-annual

nest-site fidelity, courting flocks of reproductively advanced, nuptial plumaged birds commonly occur adjacent to potential colony sites (e.g. Crested Tern - Dunlop 1987, Little Terns - Cramp et al. 1985, Sooty Tern - Ashmole 1963, and J.N. Dunlop pers. obs.). In Western Australia, ‘clubs’ are social roosts that are occupied by birds in breeding condition, have nuptial plumage, are courting and are ready to breed. Here pair bonds form or reform and these clubs are usually in close proximity to the breeding site.

These areas are critical to the social ecology of the species. Terns in these pre-breeding flocks are typically engaged in bouts of aerial courtship ‘social flights’ and ground displays or parades at diurnal club sites (Cabot and Nisbet 2013). Pairs form or re-form in these flocks and paired courtship displays frequently follow bouts of group behaviour.

In Western Australia, the timing of colony formation and egg-laying is likely dictated by food availability, with colonies forming close to areas of high food abundance (Dunlop 1987). Colonies may occur at the same general location for a series of seasons and then shift (Dunlop 2018). Some observations indicate that a ‘neighbourhood’ of

breeding terns return to the breeding site used in the previous year during the ‘clubbing’ phase but may then move in a coordinated way to a fresh location (Dunlop 1987, Sooty Tern - J.N. Dunlop pers. obs.). This behavioural pattern may assist in maintaining pair bonds together with providing the opportunity to synchronise timely breeding with neighbours of similar age/experience or quality. Younger, less experienced terns tend

to lag in their reproductive cycle, lay later outside the peak foraging window and, as a consequence, have reduced breeding success compared to more experienced pairs (Dunlop 2018).

Male Australian Fairy Terns feed whole fish to their mates in a coition display that precedes copulation (Serventy et al. 1971). Other inshore feeding terns also carry fish crosswise in their bills to clubs as ornaments in group and paired displays, however in these species courtship feeding is not an obligate prelude to mating (Dunlop 2018).

Males also feed their mates whilst they are incubating. It is likely that the ability of male terns to provision females is an important indicator of mate quality and increases breeding performance, as it does in the Common Tern (Nisbet 1973).

 Breeding

In Australia, the subspecies breeds between June and March in colonies of various sizes (generally between 2–400 pairs but up to 700 pairs in Western Australia (Dunlop et

al. 2015; Dunlop 2018). Colonies can be located on coral shingle on coastal islands, or coral cays, on sandy islands and beaches inside estuaries, and open sandy beaches, laying 1–2 eggs (rarely 3) in a nest scrape (Higgins and Davies 1996). They nest in clear view of the water and on sites where the substrate is either sandy or on shell-grit and the vegetation sparse. In Western Port Ramsar site, Victoria, birds use seagrass covered beaches to nest on Rams Island.

Incubation duties are shared but females probably spend more time at the nest whilst males actively provision females before and after laying, as is the case with Little Terns (Cramp 1985; Cabot and Nisbet 2013). Incubation lasts for approximately 18–22 days (Lindsey 1986; Higgins and Davies 1996). Chicks may be guarded by one parent for the first day or two. However, it is not unusual for chicks to be left alone whilst the adults undertake foraging bouts (C. N. Greenwell. pers. comm. 2020). Chicks fledge at about 20 days. Nesting birds are sensitive to disturbance and can become extremely agitated when disturbed by humans or other animals. Females often crouch on the ground; however both sexes have been known to attack intruders (Higgins and Davies 1996; Lindsey 1986).

There is a high natural rate of breeding failure as breeding sites can become inundated during extreme weather events, such as high tides and storm surges or be smothered by wind-blown sand. Colonies tend to occupy areas rather than fixed sites, and nest sites can be abandoned after one or more years, even if they have been successful (Saunders and de Rebeira 1985).

Interbreeding has been recorded between Fairy Terns and the Little Tern in South Australia (Cox and Close 1977), Victoria (Norman et al. 1996), NSW (Ross et al. 1999) and Tasmania (E.J. Woehler pers. obs).

 Feeding

Australian Fairy Terns hover and then dive into shallow waters in order to catch small baitfish; however they may scavenge from shoals of feeding predatory fish (Higgins and Davies 1996; Dunlop 2018). Australian Fairy Terns feed almost entirely on fish in near-shore waters adjacent to nesting colonies and around island archipelagos (Higgins and Davis 1996). Fish species consumed include Australian

Anchovies (Engraulis australis), Pilchards (Sardinops neopilchardus), Striped Trumpeter (Latris lineata) and Blue Sprats (Spratelloides robustus) (Taylor and Roe 2007; E. Stephens pers. comm 2020). Fairy Terns have been observed opportunistically feeding on small squids during twilight hours (C. N. Greenwell pers. obs).

In south-west Western Australian coastal locations, Australian Fairy Terns have been observed carrying Hardyheads (Pranesus ogilbyi), Whitebait (Hyperlophus vittatus), and Bluesprat up to about 60 mm in length (Dunlop 2018) and Southern Sea Garfish (Hyporhamphus melanochir), Two-by-three Garfish (Hemiramphus robustus), Snub-nosed Garfish (Arrhamphus sclerolepis) and flying fish (Exocoetidae spp.) up to

~150 mm in length (C. N. Greenwell pers. obs.). At the Abrolhos Islands, Australian Fairy Terns handled during banding operations regurgitated Hardyheads between 20 and

50 mm and, surface-schooling, post-larvae of the Black-spot Goatfish (Parupeneus signatus), approximately 20–40 mm (Dunlop 2018; J.N. Dunlop pers. obs). In estuarine environments, Gobiidae spp. and Western Hardyheads (Leptatherina wallacei) are important dietary constituents (C. N. Greenwell pers. obs). Contemporary dietary studies in eastern Australia are lacking and require further investigation.

1.7            Habitat critical to the survival of the Australian Fairy Tern

As noted above, the habitat, or biophysical environment, of the Australian Fairy Tern varies across its range, so it is not possible to generate one detailed description or definition of habitat critical to survival. The habitat critical to the survival of the Australian Fairy Tern may be more usefully defined at a bioregional scale that takes into account the local combination of plants, animals, geology, landforms, and climate that are relevant to a geographical unit. However, any categorisation of habitat critical to survival must acknowledge that it exists as a mosaic of coastal habitats and the adverse effects of extant threats.

In general, Australian Fairy Terns utilise a variety of habitats including offshore, estuarine or lacustrine (lake) islands, coastal wetlands, beaches and sand spits.

The species migrates within southern and mid-west Western Australia and possibly Tasmania, where they are seen less frequently during the winter months. The Tasmanian and Victorian populations may form a single subpopulation. The species is more sedentary in the north of Western Australia (Hill et al. 1988; Dunlop 2018). Australian Fairy Terns nest above the high water mark often in clear view of the water and on sites where the substrate is sandy and the vegetation low and sparse. Nests typically consist of a shallow scrape in the sand which is often lined with small shells and vegetation.

Birds will utilise seagrass covered beaches for nesting in Victoria.

As a guide, habitat critical to the survival of the Australian Fairy Tern can be considered to comprise:

•       suitable habitat where the species is known or likely to breed or forage as shown in the indicative distribution map (Figure 1)

•       any suitable habitat outside the above area that may be periodically occupied by non-breeding Australian Fairy Terns.

Habitat critical to the survival of the Australian Fairy Tern is centred on beaches and offshore islands (for nesting) and near-shore waters (for foraging) and occurs across a wide range of land tenures, including on Indigenous Protected Areas, freehold land, state reserves, and national parks. It is essential that the locations where the species regularly occurs are given the highest protection, as they are likely to be productive habitats

with high resource availability. Conservation measures should target these productive habitats. Sympathetic management of buffer areas adjoining nesting and foraging habitats is also important.

When considering developments in any part of the species range, including in areas where the species ‘may occur’, surveys for occupancy at the appropriate times

(See 2.6 Ecology) of the year are an important tool in establishing the areas of importance for the Australian Fairy Tern. In addition, it is also important to note that the Australian Fairy Tern opportunistically use areas depending on the occurrence of prey species. As such, it is critical to understand the interactions between marine

and terrestrial factors and their influence on the areas used by Australian Fairy Terns. Areas that may be important habitat over time might not have birds in any given year. This pattern of ephemeral habitat use means that recent survey data and historical records need to be considered when assessing the relative importance of an area for the Australian Fairy Tern. Regular monitoring of known breeding sites will assist in determining local extent of inter-annual variation in colony size and use.

Chapter 2

Threats

2.1            Historical causes of decline

The Australian Fairy Tern population has been in decreasing for at least the last 30 years (Garnett et al. 2011). The decrease is most prominent in the eastern population and is associated with the loss of key nesting habitats and disturbance from an increasing human population.

2.2            Current threatening processes

The main threat to the Australian Fairy Tern is the disturbance of breeding sites by human activities (including bikes, dogs, horses, drones and vehicles) and predation by introduced species and native birds (TSSC 2011; Garnett et al. 2011; Dunlop 2018). Disturbance of breeding birds may cause direct loss of eggs and chicks or the abandonment of nesting sites resulting in egg-predation or chilling, or overheating of eggs, leading to egg death (Higgins and Davies 1996). Predators of the Australian Fairy Tern include Foxes (Vulpes vulpes), Dogs (Canis familiaris), Cats (Felis catus),

Black Rats (Rattus rattus), Silver Gulls (Chroicocephalus novaehollandiae), Pacific Gulls (Larus pacificus), raptors and ravens (Corvus spp.) (Saunders and de Rebeira 1985; Hill et al. 1988; TSSC 2011; Greenwell et al. 2019). Proximity to roads is also another threat for chicks that are fledging or practising flights. The species is also adversely impacted by extreme weather events such as heavy rainstorms and storm surges that reduce breeding success. It is the species’ nesting habitat preferences that make the Australian Fairy Tern so susceptible to disturbance, predation and extreme weather events.

Any threats in or around the breeding sites can be detrimental to the colony. Threats include overgrown vegetation, weed encroachment, land development, extreme weather events, extreme salinities, unsuitable sand management and water management in waters surrounding breeding sites (Higgins and Davies 1996; TSSC 2011; E. Stephens pers comm. 2020).

Furthermore, increased salinity in waters adjacent to breeding colonies (the Coorong, Lakes Alexandrina and Albert Wetland Ramsar site, South Australia) can cause changes to local populations of prey fish abundance and distribution. Nest flooding or an increased exposure to predators can occur due to a rise or decrease in water levels, respectively (TSSC 2011).

In the event of an oil spill or ship-related oil spills, the Australian Fairy Tern could be potentially threatened due to the proximity of the species’ coastal breeding and inshore feeding habitats to known and potential offshore oil facilities, shipping facilities and sea routes (TSSC 2011).

2.2.1     Habitat degradation and loss of breeding habitat

Australian Fairy Terns do not necessarily retain the same nest site from one breeding attempt to the next (Dunlop 2018). However, colonies may establish in the same general locations in consecutive years or re-use certain places intermittently (Dunlop 2018).

Shoreline sites may be subject to rapid change due to sand erosion or accretion, tidal cycles and sea-levels, beach-wrack movement and deliberate modification. Locations that have been used in the past may be lost, become less attractive to the terns or become subject to increased disturbance or predation (Dunlop 2018). The shifting of nesting sites may be a strategy to reduce predation risks (J.N. Dunlop pers. comm. 2020).

Colony sites that are attractive to breeding pairs may develop naturally or result from coastal development activity including the clearing or loss of dune vegetation, the dumping of dredge spoil or beach-engineering (Dunlop 2018). Clearing of near

coastal areas for development (industrial or residential) can render the area attractive to breeding terns, leading to their rapid colonisation of the site earmarked for development/works. This can lead to conflict between the primary intended use of the land and its occupation by a threatened species. In Western Australia for example, this occurred on a reclaimed seabed area of the Fremantle Harbour, leading to the creation of the Rous Head Fairy Tern Sanctuary by Fremantle Ports and this is now one of the most successful breeding locations for the species. Some sites, which are well above the coastal strand, may become vegetated with native dune vegetation or covered by introduced weeds, making them unusable.

Intervention may be necessary to increase the probability that one or more secure sites will be used, or alternatively, to prevent breeding Australian Fairy Terns being attracted to inappropriate locations (Dunlop 2018). Potential breeding sites that result from development footprints or coastal engineering may put nesting terns at risk of breeding failure and increased adult mortality (Dunlop 2018).

In the absence of sufficient protected breeding sites in the local coastal system, steps may have to be taken to enhance the attractiveness of either naturally developing or artificial habitats (Dunlop 2018). This could involve reducing the vegetation cover, contouring the surface to produce low berms or adding shell or limestone pebble material to otherwise visually uniform substrates (Dunlop 2018). Local shell material to enhance preferred nesting sites has been sourced from Pacific Gull feeding stations, and in one case, from the coarse screenings from a marine lime-sand operation. In the absence of cover for the chicks at the margins of a planned nesting area, simple shading ‘chick-shelters’ can be placed to increase fledging success (Dunlop 2018). These can often be constructed from local rocks or driftwood or purpose built.

In coastal systems where human use pressures now prevent Australian Fairy Terns from breeding successfully, there is growing interest in establishing secure artificial sites (Dunlop 2018). These may be dredge-spoil islands in strategic locations or even floating islands and nesting platforms landscaped to provide breeding habitat. In the absence of legal protections however, even these sites may not be secure from human disturbance.

2.2.2     Disturbance

The presence of people, and/or their dogs, within 80–100 metres of an Australian Fairy Tern breeding colony will elicit an anti-predator response (BirdLife Australia 2018).

The nest-tending adults will take to the air to avoid disclosing the location of their eggs and/or young, and will then engage in noisy corporate dives on intruders. Direct physical contact is avoided but the terns will accurately defecate on interlopers or foreign objects within the nesting area.

Ongoing disturbance events during the colony establishment or early-laying period will often lead to the abandonment of the site (a predator avoidance response).

Although, relaying a clutch of eggs may occur elsewhere in the coastal system if eggs are lost early in the season, protracted disturbance later in the nesting cycle may cause unattended eggs or chicks to chill or overheat or starve, leading to egg loss and chick death, or clutches may be buried in moving sand or attract predators.

Commensal predators such as gulls, ravens or dogs may follow people (or their rubbish) to colonies and then prey on Australian Fairy Tern eggs or chicks. Gulls and ravens in particular have been known to opportunistically plunder exposed nests during periods of human disturbance.

A number of successful strategies have been employed to try and protect beach nesting birds (including Hooded Plover, Little and Australian Fairy Terns) from human disturbance. These are chick shelters, community education, signage (combined with boundary delineation) and volunteer wardens. However, education does not work on its own without an holistic strategic approach combining education, on-ground cues (e.g. signs/fences), compliance patrols and reviews of effectiveness/staged responses.

2.2.3     Invasive species

Most Australian seabirds breed on islands to avoid mammalian predators.

However, Australian Fairy Terns also breed at sites along the coastline presumably because they are accessible to near-shore concentrations of small fishes (Dunlop 2018). The breeding strategy adopted by the species (including the regular shifts in nesting areas) is probably, in part, an adaptation to avoid targeting by land-based predators (Dunlop 2018).

At mainland sites, the major mammalian predators of Australian Fairy Tern nests are foxes, cats, rats and dogs (Dunlop 2018; Greenwell et al. 2019; Stephens and Lamanna 2019). Baiting programs for foxes, cats and rats can be carried out on the island nature reserves and at remote coastal locations but are generally not an option in public spaces, such as coastal recreation areas, due to the risks to non-target species including pet animals. Soft-jaw traps baited with scent lures (urine or faeces) can be an effective,

low risk method, for the targeted removal of foxes and cats in peri-urban and rural areas. These traps are designed for live capture and are not in themselves likely to harm the predator or other non-target animals (e.g. domestic dogs). The use of scent lures rather than food baits reduces their attractiveness to other species. Another method for problem foxes or cats around colonies is engaging a trained shooter. Baiting programs, trapping, engaging a trained shooter and other controls methods are subject to relevant approvals from the relevant state or territory agencies.

Some colonies in Tasmania are threatened with the establishment and expansion of Sea Spurge (Euphorbia paralias), a coastal plant from the Mediterranean. The plant is tolerant of salt water and establishes coastal meadows that alienate and fragment coastal breeding sites for Australian Fairy Terns (E.J. Woehler unpubl. data).

2.2.4     Native wildlife

Raptors, such as Whistling Kites (Milvus sphenurus), Silver Gulls and Australian Ravens are the principal avian predators of eggs and chicks on mainland Australia (Dunlop 2018; Stephens and Lamanna 2019). During the surveillance of potential breeding sites it is useful to detect evidence of predator activity either from direct observation or from tracks (including prepared sand-pads) or using motion-detector cameras (Dunlop 2018). Any anti-predator interventions need to be timely if they are going to be effective.

Land managers need to be aware that the presence of people around colonies, including staff and conservation volunteers/wardens, may attract predators (that are also scavengers) to a colony area or provide opportunities for them to locate and plunder the nests (Dunlop 2018). Signs, fence-posts and other structures erected to protect colonies may become observation posts for gulls, ravens or birds of prey, increasing the risk of predation (spikes in the top of fence posts can prevent this). Rubbish bins or fish-cleaning stations near beaches with Australian Fairy Tern colonies can attract gulls, ravens and rats, and should be relocated.

2.2.5     Climate variability and change