North Head Sanctuary

The Sanctuary

North Head Sanctuary is a sandstone headland on the northern side of Sydney Harbour, connected to the mainland only by a sand spit. It is an outlying remnant of the Hornsby Plateau, and supports a diverse range of habitats. North Head Sanctuary is located on the highest part of the peninsula and encompasses shrub, open banksia heath, forest/woodland and sections of littoral rainforest, fern and wetland vegetation communities.

North Head Sanctuary is located on Sydney Harbour Federation Trust (SHFT) land and was historically used by the Australian Defence Force prior to and during World War II, and the School of Artillery up until 1998, before it was opened to the public in 2007.

The dominant habitat of North Head Sanctuary is Eastern Suburbs Banksia Scrub. This endangered ecological community now covers less than three per cent of its original distribution, and North Head is home to half of all that remains. It contains a wide composition of flora species including Banksia and Xanthorrhoea species, Tea Tree (Melaleuca alternifolia), and small native forbs, grasses and shrubs. However, sections of the Banksia Scrub are deteriorating due to Tea Tree dominating and excluding the regeneration of other plants.

There is a network of hanging swamp wetlands in North Head, with pockets of heath, fern, shrubland and forest. Several rare and endangered flora species also persist here including Camfields Stringybark (Eucalyptus camfieldii), the Sunshine Wattle (Acacia terminalis subsp. terminalis) and Hairy Geebung (Persoonia hirsuta).

The white quartz covered sand dunes at the centre of North Head Sanctuary are some of the last examples of undisturbed, vegetated, high-level sand dunes in the Sydney region. Characteristic of the Eastern Suburbs Banksia Scrub community, nutrient poor soils of Aeolian dune sands overlay the Hawkesbury Sandstone throughout much of North Head Sanctuary. The area has a temperate climate, and rainfall is spread throughout the year. Bushfire season runs from October to March.

Wildlife at North Head 

Despite its proximity to Sydney, North Head Sanctuary is relatively isolated due to its geography and historical use. Along with active management, this has allowed a number of species to persist in the area, and the sanctuary is now home to a diverse array of flora and fauna. Notable species include an endangered population of the Long-nosed Bandicoot, as well as threatened species such as the Eastern Bentwing-Bat, Grey-headed Flying-fox, Powerful Owl and Barking Owl and the federally listed Large-eared Pied Bat. 

Long-nosed Bandicoots were once widespread and common in Sydney, but are now restricted to a few populations, including a small isolated population (less than 170 individuals) on North Head Sanctuary. They are vulnerable to predation by cats and foxes, like many other mammals of their size. AWC is working to protect the North Head Sanctuary population, by monitoring numbers (in conjunction with NPWS), keeping track of threats, and researching vegetation restoration and its value for bandicoots.  

However, like the rest of Australia, North Head Sanctuary has suffered local extinction of a suite of species since European settlement, most notably the Brown Antechinus (Antechinus stuartii), Eastern Pygmy Possum (Cercartetus nanus), Eastern Quoll (Dasyurus viverrinus), Spotted-tailed Quoll (Dasyurus maculatus), Swamp Wallaby (Wallabia bicolor) and Bush Rat (Rattus fuscipes). The reintroduction of locally extinct species and the resumption of the ecological processes in which these species participate (e.g., seed and spore dispersal, pollination, herbivory, predation) is an important component of the ecological restoration of North Head. 

AWC Field Programs at North Head Sanctuary

AWC’s primary focus at North Head Sanctuary is the conservation of surviving native species, and the return of locally extinct species such as the native Bush Rat. This is achieved through a program of feral predator and herbivore control, fire and weed management. AWC also implements a range of science projects relevant to the restoration of the biodiversity of North Head Sanctuary. 

The cats on North Head Sanctuary are predominantly domestic pets that make forays into bushland and attack local fauna. The density of foxes in the areas surrounding North Head Sanctuary is relatively low, however foxes occasionally disperse to the headland where they can cause high mortality amongst native wildlife if not rapidly detected and eradicated. The small, isolated population of Long-nosed Bandicoots on North Head are particularly susceptible to foxes and cats. AWC is using a range of techniques to monitor North Head Sanctuary for incursions of feral predators, including spotlighting and infra-red cameras. 

Weed control is implemented by SHFT and supported by the North Head Foundation. 

Fire on North Head Sanctuary is jointly managed by SHFT, New South Wales National Parks and Wildlife Service (NPWS) and other government agencies. Fire management is not conducted by AWC, but AWC provide scientific support related to the role and impact of fire on the habitats of North Head Sanctuary, particularly the Eastern Suburbs Banksia Scrub.

In October 2020 a hazard reduction burn jumped containment lines and destroyed a substantial section of the AWC project area. AWC ecologists responded quickly by rescuing wildlife, creating shelters and assessing the impact to the headland. Wildlife and habitat recovery is ongoing. Prior to this, most of North Head Sanctuary had not been burnt for over 50 years.

Wildlife Reintroductions at North Head Sanctuary

Like much of Sydney, North Head Sanctuary has lost a suite of native mammals since European settlement. AWC is restoring the faunal diversity of North Head Sanctuay through a reintroduction program of locally extinct species. Since 2014, AWC has reintroduced three species:  

• 180 Bush Rats have been reintroduced to North Head Sanctuary between 2014 and 2016, and monitoring indicates that this has been very successful. Their presence at all trap sites over the headland shows that the population has successfully expanded from the original 15-ha release site to spread across the majority of North Head Sanctuary. Importantly, Bush Rats now significantly outnumber the previously dominant black rat at all sites! This indicates that North Head Sanctuary’s Bush Rats are out competing and defending territories from the invasive species, which has replaced native rodents in much of Sydney’s remnant habitat.  

•  48 Eastern Pygmy Possums have been reintroduced to North Head Sanctuary – where the species is locally-extinct – between 2016 and 2020. Between 2019 and 2021 capture rates more than doubled, with nest box checks revealing a large number of new individuals (many with pouch young). In addition to excellent capture rates, they continue to spread across the headland. Elsewhere, the species is under threat from habitat loss, foxes and feral cats, and changing fire patterns, and is locally extinct in many areas. 

• 75 Brown Antechinus have been reintroduced to North Head Sanctuary between 2017 and 2019. Monitoring has revealed their presence at multiple locations, and videos have captured them feeding on Banksia inflorescences – a very positive sign given their naturally high annual mortality post-breeding (i.e., total male die-off, and significant annual female mortality) and their fragile future due to habitat loss, predation by cats and foxes, and changing fire patterns. 

Through the reintroduction of these three species, AWC has increased the native mammal assemblage on the headland from five to eight species. Prior to this work, no native mammals smaller than ~700 grams persisted. These reintroductions are helping to restore the ecological role of native small mammal species as pollinators on North Head Sanctuary, particularly in relation to Banksia species within the critically endangered ecological community Eastern Suburbs Banksia Scrub. 

Science at North Head Sanctuary 

AWC carries out monitoring and research to track the outcomes of the species reintroductions and their effects on the wider ecological process at North Head Sanctuary. Reintroduction success is measured against a set of pre-determined criteria, including the establishment of sustainable populations, and through targeted research programs to investigate how the reintroduced animals use the habitats.

We also look at interactions amongst reintroduced species, and their relationships with feral animals; for example, we have shown that native Bush Rats can defend territories from invasive black rats.  

AWC is currently developing strategies to enhance the conservation value of the headland by sustaining reintroduced populations and identifying other species that could also be reintroduced.

Following the 2020 fire at North Head Sanctuary, AWC developed post-fire management strategies to maximise the survival of persisting wildlife. In particular, artificial provisions (food, water, shelter) supplement what dense vegetation once provided, increasing chances of survival by maintaining provisions until burnt habitat regenerates and sufficient resources become available. Via camera monitoring, trapping and regular assessments, ecologists gather data on provision usage, activity and animal health to assess the utility and future viability of post-fire interventions: 

• 32 supplementary feeding stations were established across 16 sites (1 x ground and 1 x tree) in conjunction with NPSW and Murdoch University. The project will run for 6 months throughout 2021, with food consumption measured and activity monitored by camera. A final research paper will be written by AWC in partnership with NPWS and Murdoch University.

• 18 refuge tunnels were deployed across the headland. The tunnels are part of PhD candidate Angela Rana’s project and will continue to be left for the duration of 2021.   

• 12 Bandicoot Bungalow refuges have been deployed in conjunction with NPWS and The University of Sydney. The bungalows, which aim to provide shelter for Long-nosed Bandicoots too large for refuge tunnels, will be monitored via cameras to assess usage and activity. 

• Additional nest boxes were deployed in November 2020 to provide shelter for reintroduced Eastern Pygmy-possums and Brown Antechinus, post-fire.

• Biodegradable Habitat Pods have been proposed for deployment in 2021, in conjunction with NPWS, University of Sydney, Macquarie University and Reef Design. These biodegradable refuges will be installed at burnt sites, and their effectiveness for enhancing wildlife and vegetation recovery will be investigated. Made of a recycled paper pulp, pressed into 3D-printed moulds, and coated in beeswax to repel water, they will biodegrade over 12 months.