Chestnut-sided Shrike-Vireo

A humid pine-oak specialist, this species is restricted to montane habitats from central Mexico (Jalisco and San Luis Potosí) to southern Guatemala. It is nowhere common, having one of the lowest relative abundances of any medium-sized songbird in Oaxacan pine-oak forests. In all regions, it is confined to tropical and subtropical forests zones, mostly above 1,800 metres (5,900 ft). In San Luis Potosí, this species is found principally between 4,000 feet (1,200 m) to 6,700 feet (2,000 m) in elevation. Similarly, a study in Jalisco only recorded this species above 1,400 metres (4,600 ft), with most birds found between 1,800 metres (5,900 ft) and the highest elevations of the study area, 2,000 metres (6,600 ft).

Male chestnut-sided shrike-vireos sing the most during the nest-building phase of the breeding cycle in May, and show reduced vocal activity during the non-breeding season. Song bouts are usually approximately a minute in length, delivered with the body held between 50 and 80 degrees above the horizontal and the bill held perpendicular to the body, and delivered with as few as ten minutes between song bouts in the breeding season. Birds will respond to playback, and give a variety of contact, distress, and territorial calls depending on the situation (see Vocalizations above).

Forages for arthropods (including caterpillars, wasps, grasshoppers, bugs, spiders, and beetles) primarily in the leaves and epiphytic vegetation in the inner foliage of trees. Large arthropods, over approximately 70 millimetres (2.8 in), will be beaten to death in the branches and sometimes held in the feet and dissected with the bill. Birds will less commonly eat vegetation and engage in frugivory. These birds prefer to stay in the mid-height of the tree but sometimes moving almost to the ground and up into the higher portions of the vegetation. Forage alone or in pairs, these birds are most active in the morning and late afternoon, often methodically moving from perch to perch approximately 1 metre (3.3 ft) at a time. Occasionally joins mixed-species flocks.