Cacomantis variolosus ( Vigors & Horsfield, 1827 )

Wu, Meng Yue, Schodde, Richard & Rheindt, Frank E., 2022, Integrating voice and phenotype in a revision of the brush cuckoo Cacomantis variolosus (Aves: Cuculidae) complex, Zootaxa 5091 (1), pp. 69-106 : 95

4.4 Cacomantis variolosus ( Vigors & Horsfield, 1827)

Range: Moluccas, Timor-Rote, Australia, New Guinea and its satellite islands, Bismarck Archipelago.

Diagnosis: main song of one type, elements consistently and characteristically ‘M’-shaped ( Fig. 2 ) and delivered at moderate pace; basic morph of Australasian morphotype that varies from pale to dark (see 3.2.2(3) above); body medium-sized to large and tail proportionally short to mid-length: wing c. 115–145 mm, tail/wing ratio 0.80– 1.06 ( Table 2 ); barred females with dorsa grading from plain with russet flecking on shoulders in paler populations to dully barred dusky on cinnamon in darker birds, and ventral white barred finely dusky in paler populations to boldly black in darker ones, with light to moderate cinnamon wash; juveniles ranging from dark in tone and clouded in markings to pale, brightly and coarsely patterned (Australian populations). In this group, the acoustic impression of the elements of the main song is dominated by the final deflection ( Fig. 2 ). This is reflected quantitatively in terms of the frequency change between element sections, with significant differences from elements in all other primary differentiates ( Fig. 4 ). Element duration is also generally longer, with some overlap only with Sundaic populations ( Fig. 4 ).

This species, known traditionally as the “Brush Cuckoo” throughout Australasia, varies more regionally than any other in the variolosus complex, and has differentiated into 8–9 subspecies, as detailed below (see 4.4.1 following).

Figures

FIGURE 2. The seven element shapes found in the Cacomantis variolosus complex. Taxon names given represent the following geographic song types (see Results): sepulcralis—Sundaland and Philippines, virescens—Sulawesi and Sula, aeruginosus—resident Moluccas, variolosus—Australasia, blandus—Admiralty Islands, addendus—Solomon Islands.

FIGURE 4. Boxplots of vocal measurements. Explanation of variables: pacing—elements per second; element duration in seconds; changes in center frequency in Hertz. For further explanation of vocal parameters, see Methods.