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once widespread and apparently common in the mountains of mainland Mexico, to which it is endemic, the Cinereous owl (Strix sartorii) seems to have declined precipitously. in 2015, 2016, 2017, and 2019 we searched for the Cinereous owl in eight Mexican states where it had been reported previously. We detected it at only a single site, rancho la Noria on Cerro San Juan, Nayarit. our results suggest that the Cinereous owl may have disappeared from much of its former range, and that the Fulvous owl (Strix fulvescens) may now inhabit areas in oaxaca formerly occupied by the Cinereous owl, perhaps as a result of habitat alteration. The Cinereous owl may qualify for recognition as vulnerable or endangered. Comprehensive surveys are urgently needed to establish its current status and distribution. Such surveys should also be used to determine the current distribution of the Fulvous owl, and to investigate the reasons why it now occurs in areas formerly occupied by the Cinereous owl.

the proportionately longer nasal bristles of the Chihuahuan raven (Corvus cryptoleucus) have been adduced as a character distinguishing that species from the Common raven (C. corax). in a sample of 113 specimens of the Common raven and 86 of the Chihuahuan we confirmed that the average of the bristle-to-bill ratio differs significantly in the two species, being 26% greater in the Chihuahuan. But the overlap is wide: only 36% of the Chihuahuan ravens and 22% of the Common ravens fell outside the zone of overlap. on the basis of this character, only ravens with a ratio <0.45 can be identified as the Common, while those with a ratio >0.60 are almost all Chihuahuan.