Justification of Red List Category
This species has a suspected population size of 5,000-15,000 mature individuals and although this species was formerly in decline it is now suspected to be stable, if not increasing. For these reasons it is assessed as Least Concern.
The species is often divided into three forms (although it is taxonomically considered monotypic herein): 'Bush', 'Southern' and 'Eastern' (Marchant and Higgins 1993). Population estimates by Fox (1978) are as follows: 'Bush' form (North Island and north-west South Island) 450-850 pairs; 'Southern' form (south-west coast of South Island and Auckland Islands) 140-270 pairs; and 'Eastern' form (of the remainder of South Island) 3,100-3,200. Thus the population was then estimated at 7,400-8,800 mature individuals. No more recent estimate has been made and since this time some populations have declined and/or recovered in ways that introduce considerable uncertainty to data more than 40 years on. For these reasons, the population is now suspected to number 5,000-15,000 mature individuals.
F. novaeseelandiae formerly declined because of habitat destruction, persecution and the effects of DDT. However, it has been comparatively tolerant of pervasive habitat modification throughout New Zealand, breeding successfully in plantations and feeding principally on non-native birds and mammals (Marchant and Higgins 1993, Ferguson-Lees and Christie 2001, Seaton 2009). Some populations have been recorded declining (Gaze and Hutzler 2004) and the species has apparently become extinct on Stewart Island (Bell 2017). The 'Bush' form is listed nationally as 'Nationally Increasing' (Robertson et al. 2021; according to criteria established by Townsend et al. 2008), indicating that the species has formerly declined (within the last 1,000 years) but now has an ongoing or predicted increase of >10% (in population size or area of occupancy) over the next three generations. The 'Eastern' form, which was previously thought to be increasing, is now listed as 'Nationally Vulnerable' due to its small, stable population which is predicted to remain stable over the next three generations. The 'Southern' form (comprising <5% of the global population) is thought to number less than 1,000 mature individuals and is therefore listed as 'Nationally Endangered,' however under criteria (sensu Townsend et al. 2008) that indicate that the small population is stable and predicted to remain stable over the next three generations. The quality of these data are however poor (Robertson et al. 2021) and require confirmation. The global population of F. novaeseelandiae is precautionarily therefore suspected to be stable, however may be increasing.
Falco novaeseelandiae is endemic to New Zealand where it is widespread on both the North Island and South Island (Bell 2017). It occurs also in the Auckland Islands, where it is known from Adams, Enderby, Figure of Eight, Auckland and Rose; there are two records from Campbell Island (Miskelly et al. 2020).
It occurs predominantly in bush and forest, and the 'Eastern' form also breeds in rough farmland and dry tussockland. The species also breeds in exotic pine plantations (Stewart and Hyde 2004); this is now recognised as a major habitat for the species (Pawson et al. 2010) and extremely high densities can be supported (Seaton 2009). Adults are mainly sedentary but juveniles wander widely and are seen in farmland, orchards and urban areas. Juvenile dispersal may occur earlier in exotic pine plantations (Seaton et al. 2008). Established pairs remain on territory all year and display during late winter and early spring before nesting in September-December. When food availability is high females may breed in their first year (Seaton and Hyde 2008), though age of sexual maturity is typically considered 20 months (Marchant and Higgins 1993). The majority of prey taken are small passerines (Seaton et al. 2008), although prey species several times heavier than the falcon have also been recorded (Hyde and Seaton 2008).
Introduced brush-tailed possum Trichosurus vulpecula take eggs (Gaze and Hutzler 2004). Although protected since 1970 (Marchant and Higgins 1993), birds are occasionally shot by farmers, and pigeon and poultry keepers (Heather and Robertson 1997), possibly as many as 400 a year (N. Hyde in litt. 1999). The species has been recorded as becoming impaled and dying on barbed-wire fences, but this is unlikely to be a significant cause of mortality (Allen and Ramirez 1990). The impact of electrocution, conversely, may be severe since of 21 radio-tagged individuals known to have died during a 5-year study, 10 of which were electrocuted (Fox and Wynn 2010).
Conservation Actions Underway
CITES Appendix II. Research into the use of exotic pine plantations by this species is ongoing using radiotracking and colour-banding (e.g., Seaton 2009, Seaton et al. 2010).
43 cm. Small, dark brown raptor. Head, nape, back, wings and tail dark dark brownish-black with all except head barred buff; thin rufous eyebrow; base of bill and chin white, throat and side of neck buff streaked dark brown; breast and belly dark brown; cere, legs and feet yellow; juvenile more dark with less distinctive markings. Similar species: Swamp Harrier Circus approximans is much larger, with long fingered wings. Voice: Loud rapid 'kek-kek-kek'.
Text account compilers
Martin, R., Berryman, A.
Bird, J., Hyde, N. & Stewart, D.
BirdLife International (2023) Species factsheet: Falco novaeseelandiae. Downloaded from http://www.birdlife.org on 27/01/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/01/2023.