Phascogale pirata was considered a subspecies of P. tapoatafa by Groves (2005). Recent taxonomic work, however, suggests that P. tapoatafa sensu lato is composed of more than one species, including P. pirata, which is treated here as distinct (Rhind et al. 2001, Spencer et al. 2001; for comments, see Rhind et al. 2008).

Assessment of the conservation status of the Northern Brush-tailed Phascogale is challenging because there are few recent records and it is largely unrepresented in extensive biodiversity monitoring programs within its range (in part due to low detectability), rendering it difficult to evaluate population size and rate of decline. Although there is little robust monitoring data, decline is evident from marked reduction in records on the north Australian mainland. For example, the Atlas of Living Australia has zero records from the mainland since 2005, with the frequency of mainland records across preceding decades being: 1970-1979 (10 records); 1980-1989 (19 records); 1990-1999 (6 records); 2000-2010 (10 records); 2010-2019 (0 records); 2020-2024 (0 records). Although the rate of population decline cannot be estimated reliably; it is almost certainly greater than 30% over 10 years, and may be appreciably higher.

Based on recent records, the area of occupancy (AOO) is 116 km². This is likely to be an under-estimate given sparsity of sampling across range, and the actual value is considered here to be between 500 and 2,000 km². It is known to persist in fewer than 10 locations, and it is likely to be undergoing continuing decline in habitat quality and number of mature individuals, so qualifies as Vulnerable B2ab(i,ii,iii,v).

Population size is challenging to estimate, but is most likely less than 10,000 mature individuals and may be far fewer. The rate of decline is not resolved but is likely to be more than 10% over the last decade, so it could also qualify as Vulnerable C1, although the evidence is meagre.

The Northern Brush-tailed Phascogale is endemic to the Top End of the Northern Territory, Australia, where it has been recorded from Melville Island, West Pellew Island, and tropical savannas of the Northern Territory mainland including near Gove, near Borroloola, Katherine area, Kakadu National Park, Garig Gunak Barlu National Park, and Litchfield National Park (Parker 1973, Woinarski 2005, Rhind et al. 2008). The population on West Pellew Island is probably extirpated (Ward et al. 2006, Woinarski et al. 2011) and over the last few decades it has suffered severe declines in distributional extent and population size on the Northern Territory mainland. It has not been reported from other large islands in the region with apparently suitable habitat (e.g., Bathurst Island, Groote Eylandt).

Its continuing existence in Kakadu National Park, a former stronghold, is uncertain. The most recent records are of an individual seen in 2021, 20 km west of Jabiru (Steve Cutter, via Luke Einoder, pers. comm., August 2024) and one individual found dead in 2016 at Jim Jim ranger station (Luke Einoder, pers. comm., August 2024). With those exceptions, all recent (post 2010) records are from Melville Island, and its occurrence there is patchy (with recent records mostly from Jessie Creek, Goose Creek, and Taracumbi localities).

EOO calculated in sRedList based on all records from the Atlas of Living Australia is 218,978 km², declining to 46,678 km² when only records since 2000 are included.

Historic accounts report that the Northern Brush-tailed Phascogale was common: for example, Dahl (1897) noted that ‘on the rivers Mary and Katherine it was frequently observed. In fact nearly everywhere inland it was very constant, and on a moonlight walk one would generally expect to see this animal’. However, this is no longer the case, and it has declined severely in range and abundance over recent decades (Woinarski et al. 2007, Rhind et al. 2023). Quantifying the extent of this decline is challenging. Although there were many reports of its former abundance in Kakadu National Park in the 1970s and 1980s (Calaby 1973, Woinarski and Fisher 2014), it had declined so severely by the time that an extensive biodiversity monitoring program was established in Kakadu National Park (late 1980s) that it was recorded in so few plots that rate of decline could no longer be assessed (Woinarski et al. 2004, 2010).

In a baseline mammal monitoring program from 2000 to 2002 in its likely stronghold, Melville Island, it was reported with only two individuals from more than 25,000 trap-nights at 236 sampling sites (Firth et al. 2006), re-sampling in 2015 of 86 of those sites (using ~8,250 trap-nights) recorded only one individual (Davies et al. 2018a). To some extent, the sparsity of recent records is due to its low detectability using conventional trapping techniques. Davies et al. (2018b) used camera-trapping (48,627 trap-nights) on Melville Island (from 2013 to 2015) and reported nine detections, at a single site (Taracumbi). Geyle et al. (2020) used targeted sampling (50 baited camera traps placed in large trees and set over a 10-month period (2018-2019), at this same site on Melville Island) to improve detection, and reported 16 detections of this species.

In eucalypt woodlands at Garig Gunak Barlu National Park (Cobourg Peninsula), Woolley et al. (2024) monitored 198 nest-boxes over three years (2015-2018) and detected no phascogales.

However, in Kakadu, since 2021 Parks Australia has undertaken a targeted camera-trap survey, with cameras set at tree hollows in suitable forest, at 70 sites by 60 nights (i.e., 4200 trap-nights), but did not record any phascogales (Luke Einoder pers. comm., August 2024).

The total global population of this species is estimated to be fewer than 10,000 mature individuals and it might be fewer than 2,500.

The Northern Brush-tailed Phascogale is solitary, nocturnal, and arboreal. It nests within tree hollows during the day, and forages both on the ground and in trees mostly for invertebrates, but also some small vertebrates (Woinarski 2005). There is little information on the habitat requirements of this species. Most recent records are from tall open forest of Eucalyptus miniata-E. tetrodonta forests (Geyle et al. 2020; Rhind et al. 2023).

Threats have not been well resolved, in part because there have been no detailed ecological studies on this species. It is likely that the current fire regime characterised by high frequency of fires (Russell-Smith et al. 2017) reduces habitat quality (including abundance of tree hollows, hollow logs and large trees) and hence is detrimental to this species. In some areas within its range, this regime is being exacerbated by ongoing expansion of invasive pasture grasses (Rossiter-Rachor et al. 2023). Predation by feral cats (Felis catus) is a likely ongoing threat, and cats are abundant across at least part of its range (Davies et al. 2021); and frequent fire may cause increasing incidence or impact of such predation (McGregor et al. 2016). Cats have been implicated in the rapid and severe recent decline of other small mammals on Melville Island (Davies et al. 2021). In some parts of its mainland and Melville Island range, there has been extensive habitat clearing, mostly for horticulture and plantations (Firth et al. 2006). It is possible that the spread of invasive cane toads (Rhinella marina) across the phascogale’s entire mainland range over the last 2-3 decades may have caused major mortality and population loss, through poisoning during predation attempts, but there is no evidence for or against this possibility.

The Northern Brush-tailed Phascogale has been recorded from three protected areas: Litchfield, Garig Gunak Barlu, and Kakadu National Parks, although it may no longer persist at these. An Indigenous Protected Area was established for the Tiwi Islands (including parts of Melville) in 2024. 

The Northern Brush-tailed Phascogale is listed as Vulnerable under Australian national environmental legislation and there is an existing Conservation Advice (that provides broad conservation direction) for this species.