Christmas Island Boobook
Ninox natalis
Small, distinctive boobook with extensive chestnut-brown barring. Favors surviving primary rainforest, but can sometimes be found in secondary growth; can be found on roadsides through suitable habitat when hunting. The only resident owl on the island; the migratory Northern Boobook is a winter visitor to the island, and is significantly larger and much darker overall, with an all-brown head and brown-striped white underparts. Present species gives an odd, distorted-sounding “qwr-qwerk.” Begging birds give a shrill trill. Unfortunately, like many other Christmas Island species, has suffered declines due to the introduced yellow crazy ant, which has caused the owl to disappear from parts of its range.
Identification
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.
Taxonomy
- Scientific name
- Ninox natalis
- Authority
- Lister, 1889
- Order
- Strigiformes
- Family
- Strigidae
- Genus
- Ninox
Range and 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.
- Migration
- Resident species
Conservation
- Population trend
- stable
Photos
Distribution
Other Birds
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Chunky brown songbird with a weak crest, typically found on the ground in open fields and meadows. Darker above than below, with fine black streaking on the chest and light chestnut ear coverts with dark border. Very similar to Eurasian Skylark, with which it shares much of its range, but Oriental has buffy, not white, outer tail edges and trailing edge of wing. Breeding males “skylark,” singing a series of variable notes while hovering high above the territory.
Yellow-breasted Forest Robin
Stiphrornis mabirae
A short-tailed understory robin with a bright yellow-orange throat. Also shows a dark-green back, buff belly, and a white spot in front of the eye. Most often encountered by its song: a duet, in which the male gives high-pitched whistles and the female makes an accompanying chatter. Similar to Orange-breasted Forest Robin (potentially very limited overlap in range), but underparts more extensively yellowish-orange. Otherwise most likely to be confused with Lowland Akalat, but can always be distinguished by the white spot in front of the eye, as well as the dark-green rather than rufous-brown back, and the buff rather than white belly.
Ultramarine Flycatcher
Ficedula superciliaris
Incandescently beautiful male is resplendent in electric blue and snowy white. Female is dull gray-brown with paler underparts. Slight regional variation: “Western” males have a short white eyebrow and “Eastern” females have a faint rusty patch on the forehead. Male may be confused with Himalayan Bluetail, but lacks orange. Female is similar to females of Slaty-blue and Little Pied Flycatchers, but lacks any rufous tones on the tail. Breeds in hill and montane broadleaf and pine forests; descends into lower foothills in winter. Rarely heard song a complex series of whistles and chatters; more commonly heard is the call, a dry trilling chatter, sometimes preceded by a short whistle.
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