 Endemic to the highlands of Mexico north of the Isthmus of Tehuantepec , the red warbler has three disjunct populations : from southwestern Chihuahua to northern Nayarit , from southern Jalisco and southern Hidalgo to Oaxaca , and from Guerrero into southern Oaxaca in the Sierra Madre del Sur . It is fairly common to common in the interior and on adjacent slopes , where it occurs at elevations ranging from 1 @,@ 800 to 3 @,@ 900 metres ( 5 @,@ 900 to 12 @,@ 800 ft ) above sea level . It is an altitudinal migrant , moving from higher humid or semi @-@ humid pine , pine @-@ oak and fir forests in the breeding season to lower elevations , often in oak forests , in the winter . It is among the most common of the small birds in its woodland habitat , second only to the golden @-@ crowned kinglet in fir forests in one study and the third most common warbler in oak @-@ conifer woodlands in another . 
