Civetta delle Isole Christmas

Identificazione

The Christmas Island hawk-owl is a small, rufous-brown hawk-owl with a barred breast, dark chestnut facial mask, whitish brow, lores and throat, yellow eyes, legs and feet. It is approximately 26–29 cm in length and 130-190 grams in weight with the female slightly larger than the male.<p>Its double-noted hoot, boo-book, has a clucking quality with the second note usually lower in pitch. The begging call of juveniles is a high-pitched trill.<p>Vocalisations are similar to those described for the Australian boobook (Ninox boobook) and include individual variation in advertisement calls. This may be useful in estimating owl densities as radio-tracking can be impractical in some terrains.

Tassonomia

Nome scientifico

Ninox natalis

Autorità

Lister, 1889

Ordine

Strigiformi

Famiglia

Strigidae

Genere

Ninox

Areale e habitat

Ninox natalis is endemic to Christmas Island, a small Australian territory of about 135 square km situated in the Indian Ocean approximately 360 km (220 mi) south of Java.<p>The flora and fauna of the island face on-going threats from both human activity and introduced species of plants and animals. In addition to these threats, N. natalis is restricted to a small range on this small island and is consequently listed as vulnerable by the IUCN.<p>Phosphate mining has continued for over a century and more recently Australian Immigration Detention Facilities have been established increasing the impact from human habitation. However, the Australian National Parks and Wildlife Service manage 64% of the island as a national park. Its natural habitats are subtropical or tropical moist lowland forest and subtropical or tropical moist shrubland.<p>Ninox natalis occupies essentially exclusive territories and is widespread on the island utilizing both primary and disturbed habitats. However, in areas of regrowth significantly fewer birds have been detected. In 1995 there were approximately 560 breeding pairs, but by 2004 the population was estimated to be down to 1000 birds. A more recent estimate in 2011 suggests that the population may, however, be significantly lower than that.<p>Preferred roost sites are sheltered and concealed positions from which they can easily escape such as in the bottom third of the canopy of trees with deep crowns and mid-level understory but with fewer low understory trees.<p>Nests have been found in tree hollows predominantly in the canopies of Planchonella nitida, Hernandia ovigera and Syzygium nervosum.

Migrazione

Resident species

Conservazione

Tendenza della popolazione

stable