6o BIRDS OF THE REPUBLIC OF PANAMA PART 4 



among which it was formerly placed, by various morphological char- 

 acters and in long incubation and nestling period), Skutch suggests 

 replacing the inappropriate English name "Mockingthrush" by Dona- 

 cobius. 



CAMPYLORHYNCHUS ALBOBRUNNEUS (Lawrence), White-headed 

 Wren, Cucarachero Cabeciblanco 



Figure 8 



A large, long-tailed wren; head and undersurface white; above dark 

 blackish brown. Juvenile birds may have indistinct lines of pale gray 

 in the crown. 



Description. — Length 180-200 mm. Adult (sexes alike), head, hind- 

 neck, and undersurface (except as noted) plain white; underwing 

 coverts, tibiae and undertail coverts spotted with dusky (in varying 

 amount in the two races recognized here) ; rest of upper surface sooty 

 brown. 



Immature (in juvenile plumage), crown and side of head slightly to 

 heavily lined with dull grayish brown; tibia and undertail coverts 

 spotted in varying amount with dusky; tail in some tipped narrowly 

 and irregularly with white; duller, more brownish black above, with 

 the upper back lined and spotted lightly with white; flanks, abdomen, 

 and undertail coverts faintly to definitely washed with pale buffy brown. 

 (This pattern of markings is followed by a plumage closely similar to 

 that of the adult.) 



In recent reviews these wrens of Panama and northwestern Colom- 

 bia are listed as geographic races of the species turdinus, widely dis- 

 tributed in northern South America. The assignment has come through 

 a peculiar population of wrens found in Narino in far southwestern 

 Colombia, described by Meyer de Schauensee as Campylorhamphus 

 albobrunneus aenigmaticus (Notulae Naturae, no. 209, Acad. Nat. 

 Sci., Philadelphia, April 16, 1948). In the original description it is 

 suggested only that the new form might indicate "a hybrid between C. 

 albobrunneus and C. turdinus, but this possibility seems doubtful as 

 the latter ... is unknown west of the Andes. . . . neither species has 

 been taken. ... in Narino." J. Haffer (Veroff Zool. Staatssamml. 

 Miinchen II, 1967, pp. 143-144) suggests that it is more probable that 

 aenigmaticus is the result of hybridization between C. a. harterti and 

 C. zonatus brevirostris of northwestern Ecuador. Meyer de Schauen- 

 see (The Species of Birds of South America, 1966, p. 401) mentions 

 both hybrid possibilities. Until there is clearer understanding it is pref- 

 erable to consider albobrunneus, with its subspecies, harterti, as a sepa- 



