Physical characteristics

Birds in this family range in length from the 5 in (12.5 cm) goldenface to the 11 in (28.0 cm) rusty pitohui (Pitohui fer-rugineus). They are characterized by a robust body and large, rounded head, the latter the reason for the earlier name "thickhead" bestowed to whistlers and as a group name for the family. Legs and feet are strong, wings broad and rounded, and tail unadorned. The bills are robust, although often of moderate length and, in some of the larger species, rather imposing, especially when attached to the finger of an unwary handler. There is a shrike-like hook at the tip, part of the origin of the name "shrike-thrush" for the thrush-sized species in the genus Cotturicmda. Together with a well-developed notch, this makes the bill efficient at grasping prey. The most specialized bills are those of the shrike-tits and ploughbill. These are strongly laterally compressed, making them much deeper than wide. The shrike-tits, in particular, are endowed with powerful jaw muscles. Rictal bristles are generally not strongly developed in this family and may be absent in some forms. Members of this family rarely have adornments of the plumage or other parts of the body. The crested bellbird, crested pitohui (Pitohui cristatus), and the shrike-tits have distinct crests. The adult male ploughbill has two round, pink wattles at the base of its bill, while the bare-throated whistler

(Pachycephala nudigula) has a naked patch of colored skin on the throat.

The predominating plumage colors are rather somber— various browns, rufous, gray, and olive—with white and black less frequent, and in a few species, bright yellow. Brightly colored species often have boldly contrasting patterns. The variable pitohui (Pitohui kirhocephalus) has large areas of black and dark rufous, and a number of whistlers have a white throat, bordered by a black breast band, which separates it from differently colored underparts. Species with bright males are often sexually dimorphic, with the female being plain brownish or grayish, occasionally with streaked underparts. More drably plumaged species usually show few differences between the sexes. In the unusually patterned mottled whistler, females are much more heavily spotted than males. Chicks and juveniles of most species have an unmarked rufous plumage. Parts of this are retained in immatures, particularly on secondaries and secondary coverts; these feathers are very noticeable in some young whistlers.

The geographic variation in plumage in the golden whistler is remarkable. Across this species' distribution, the head may be gray, black, or olive; nape collar yellow or absent; throat white, yellow, or black; breast band black or absent; and back gray, olive, or black. Each population combines a different selection of these to produce marked variation in color patterns. In birds of Norfolk Island, the bright plumage of the male has been lost and both sexes resemble the brown female. Females exhibit more limited geographical variation. They can range from dull grays or browns to bright yellows approaching colors of the males.

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