Silver-backed Butcherbird Cracticus argenteus Scientific name definitions

27–30 cm. Medium-sized butcherbird with strong bill ending in sharp terminal hook. Nominate differs from C. torquatus in having completely black head (no white on lores), black chin, front lower edges of hood extending as black “necklace” onto breast, paler silvery-grey back , scapulars and rump with darker shaft streaks, broader white tail tip, more extensive white patch in wing; race <em>colletti</em> is similar but smaller, with chin and side of breast white, no “necklace”, shorter white tail tip. See also Taxonomy.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Both nominate and colletti inhabit mainly riparian forest, especially of cadjeput (Melaleuca leucadendra), vine scrub, edges of rainforest patches, thickets at foot of cliffs, fringing vegetation such as Pandanus along creeks and rivers, forest and woodland in gorges and gulleys.

Sedentary. Many anecdotal reports of seasonal movements probably refer to post-breeding dispersal of immatures, but no detailed studies. Censuses in open forest near Darwin (Northern Territory) showed numbers of race colletti similar in wet and dry seasons, suggesting that birds remain in same area all year.

Invertebrates, mainly insects , also small vertebrates, especially small birds and nestlings; some fruit and seeds, and nectar. Forages from perch , pouncing on prey on ground, sallying to seize insects on branches or trunks of trees, or striking for flying prey such as bees (Apidae) or cicadas (Cicadidae). Reported as chasing small birds in flight, but more often seizes from behind small birds which are foraging on ground, killing them by powerful spear of bill to the head; association with mixed-species foraging flocks interpreted as a strategy to prey on other birds. Also robs nests of small birds. In Northern Territory, race colletti one of a number of opportunist nectar-feeders when nectar very abundant in dry season.

Vocalizations  of argenteus and colletti little known, but that of former considered significantly different from that of C. torquatus; recordings of colletti contain unhurried phrases of mellow ringing notes more like song of Melloria quoyi and C. cassicus than of present species; also some faster jumbled phrases like those of C. torquatus.

Lays Aug–Sept (end of dry season) in NW of range (race argenteus). Nests usually in simple pairs, sometimes with a helper, usually immature from previous year. Territorial; present in territory all year. Nest built by both sexes (reportedly lined only by female), an untidy small bowl 18–23 cm across and 8–11 cm deep, internally 8·5–9 cm wide and 3–3·5 cm deep, of fine twigs, lined with spinifex grass and rootlets, usually in vertical or horizontal fork 5–15 m above ground in tree, including Melaleuca leucadendra and Eucalyptus miniata. Clutch (argenteus) 2–3 eggs, pale olive-grey or buff-brown, zone of reddish-brown spots and blotches on violet-grey at larger end, 29 mm × 21 mm; no information on incubation and nestling periods and post-fledging parental care.

Not globally threatened (Least Concern). Generally rather uncommon and patchily distributed. Population unknown and trends also unclear. In some areas, numbers have declined because of clearing of open woodland habitats for urban development or for agriculture, but in other areas forest clearance has produced the more open habitats preferred by this species. Can co-exist with man, as suburban trees and parks mature to provide suitable habitat. Main future threats are habitat alteration and loss resulting from current fire regimes.