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
Yellow-throated Bunting
Emberiza elegans
Attractive songbird of parks, forests, and meadows. The combination of crest and yellow brow and throat unmistakable. Adult male has a black chest patch, mask, and crest combined with a yellow throat and brow. Female is similar but paler and lacks any kind of chest patch. Both sexes have brown backs and lightly marked pale bellies. Usually found in small flocks, foraging within vegetation, often on the ground.
Yellow-billed Pintail
Anas georgica
Handsome and generally common dabbling duck of wetlands, lakes, and river mouths. Sexes look alike with a bright yellow bill (duller for a short while on young birds), a plain and rather “soft-faced” brown head, and dark-mottled sides. Also note its elegant shape with a slender neck and long pointed tail. Yellow-billed Teal look somewhat similar (and often occurs in same areas) but Yellow-billed Teal are smaller and more compact with a darker head and plain grayish sides.
Rufous-fronted Babbler
Cyanoderma rufifrons
Small brownish babbler with a rufous crown. Extremely similar to Rufous-capped Babbler, and often not safely distinguished in areas of overlap. Rufous-fronted averages paler-throated, grayer-faced, less yellow below, has very fine dark streaks on the crown, and may have a duller and shorter crown patch. Song is a variable ascending series of piping “toots” (short whistles): “tu-tu-tutututu!” Calls include quick isolated “chit” and “whit” notes, rolling rattles, and quick notes similar to those from the song. Found from lowlands up into the upper elevations, foraging in forests and edges with dense low vegetation. Buff-chested Babbler of northeastern South Asia and Indochina, formerly an independent species, is now treated as part of Rufous-fronted.
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