David C. Wege

The distribution and status of Worthen's Sparrow Spizella wortheni: a review

Originally described last century from New Mexico, U.S.A., Worthens Sparrow Spizella wortheni has subsequently been recorded from just eight states in Mexico centred on the interior of the north-east of the country. Records during the last 30 years originate from just Coahuila and Nuevo Leon, with those during the last 10 years exclusively from two small areas in south-eastern Coahuila and western Nuevo Leon: it appears that this poorly known species has been suffering a range contraction owing to the widespread destruction of its shrubby (mesquite or yucca-juniper) grassland habitat. Little detail is known of its specific requirements, local movements, or even its distribution, and it is proposed that Worthens Sparrow be formally recognized as a threatened species.

The distribution and conservation status of the Bearded Tachuri Polystictus pectoralis

The Bearded Tachuri Polystictus pectoralis occupies lowland grasslands with scrubby vegetation, generally near water, in the Andean grasslands of Colombia at two sites (threatened race bogotensis ), savannas in eastern Colombia and the lowland and tepui grasslands of mainly southern Venezuela, Guyana, Surinam, French Guiana and northern Brazil (race brevipennis ), reappearing south of the Amazon in central-southern Brazil, eastern Bolivia (no recent records), Paraguay, Uruguay and northern and central-eastern Argentina (nominate pectoralis ). It is an austral summer visitor (October/November to February/April) to central-east Argentina, nesting (commonly in thistles) around December, clutch-size three. It feeds on insects by perch-gleaning, sallying, hover-gleaning and still-hunting. It is unobtrusive and must be commonly overlooked, and in some localities may be moderately well represented. Overall, however, it is scarce and appears to be very patchy in occurrence; grassland habitats within its range have been converted wholesale to farming. New quantitative criteria support earlier qualitative judgement that the species is probably not (yet) threatened, but that it merits near-threatened status. Suggestions that one or all of its three subspecies may be good species are premature; it is not even clear how distinct these forms are as subspecies.