Group-living White-browed Sparrow-Weavers( Plocepassemr mahali) build their roost and breeding nests on one side of nest trees. The placement of nests correlates with the direction of the local prevailing wind. Birds gain a 35% increase in the useful life of a nest built on the leeward side of a nest tree, compared with a nest built on the windward side. Solar radiation, humidity, and thermal effects appear unimportant in influencing nest placement. Foliage density and other nearby cover does not affect nest placement. Hence, White-browed Sparrow-Weaver nest placement appears to be an adaptation for having large numbers of intact nests available for breeding and for roosting throughout the year. Key words; White-browed Sparrow-Weaver, Plocepasser, nesting, environmental physiology,heat loading, wind.