Habitat Critical to SurvivalHabitat Critical to Survival

Habitat Critical to Survival

Until the late 1700s Norfolk Island was covered in dense forests and the Green Parrot was probably widely distributed across the island. Between the late 1700s and 1800s, felling of forest tree species led to considerable deforestation. Clearing for agriculture and plantation production further reduced native vegetation cover. By the late 1800s the Green Parrot was confined to the area now included in NINP. Since then, the structure and composition of the remaining native vegetation has changed dramatically primarily through weed invasion and grazing (Anon 1984).

The most extensive area of native habitat remaining on Norfolk Island is within NINP, which encompasses 465 ha (12%) of the island. Gilmour and Helman (1989) quantified the native vegetation assemblages of the Park as 30% ‘native forest’ (palm, hardwood, and Norfolk Island Pine forest), 37% ‘weed-infested native forest’ and 33% ‘exotic forest’ (see also Schodde et al. 1983).

Green Parrots forage in all habitats within the park except for a small area of eucalypt plantation (J. Hicks, pers.comm.) and in some areas outside of the park. The principle diet of adult Green Parrots appears to be a variety of native seeds, fruits, flowers, and leaves. This includes Norfolk Island Pine (Araucaria heterophylla), Ironwood (Nestegis apetala), Norfolk Island Palm (Rhopalostylis baureri var. baueri), Bloodwood (Baloghia inophylla), Cordyline (Cordyline obtecta) and Whiteoak (Lagunaria patersonia spp. patersonia) (Forshaw 1981, Hicks and Preece 1991). Seeds, fruit and bark of some exotic species are also consumed, namely Red Guava, African Olive and Lantana (Lantana camara) (Hicks and Preece 1991).

African Olive and Red Guava seeds may now form a significant part of the diet of newly-fledged juveniles (Davidson 1997, Motte and Hall 1988), with Bloodwood seeds, Norfolk Island Pine seed and green and fallen Red Guava fruit also important (Davidson 1997).

No quantitative studies have been conducted on the foraging preferences and nutritional value of native and exotic foods in the diet of wild Green Parrots. Captive Green Parrots readily accept native Norfolk Island herbs (Chaff-flower Achyranthes aspera seed, Pig Face Carpobrotus glaucescens leaves and fruit, Mile-a-minute Wollastonia biflora flowers and fruit). Hicks and Preece (1991) note that although the NI Green Parrot feeds in forest trees, other closely related Cyanoramphus spp. occur and forage in grassland environments eg. the Kermadec Parakeet (C.n.cyanurus) on Macauley Island and the Red-fronted Parakeet (C.n.novaezelandiae) on Tiritiri Island (NZ).

Parrots typically forage from early to mid-morning, flying between favoured feeding areas in pairs or small parties (Davidson 1997, Forshaw 1981). From mid-morning to late afternoon parrots move to sunny (but unexposed) positions near the tops of trees, where they preen quietly and are inconspicuous (Forshaw 1981). Adults forage mostly in the tops of trees and occasionally on the ground (Forshaw 1981, Hicks and Preece 1991), while juveniles, for 3-5 weeks after fledging, feed extensively on the ground eating the fallen seeds of African Olive and Red Guava (Davidson 1997). Davidson (1997) recorded a total of 244 perch locations from 3 radio-tracked juveniles, of which 58 (24%) were on the ground, 101 (41%) were in African Olive and Red Guava and 85 (35%) were in 12 native tree species. It is unclear whether frequent foraging in exotic vegetation reflects a preference for olive and guava by juveniles or the widespread abundance of these species in NINP (Davidson 1997).