Bay-capped Wren-Spinetail is classified as Near Threatened in the IUCN Red List, however its population is considered to be decreasing (Bird Life International 2012). Stotz et al. (1996) describes it as fairly common although the global population has not been estimated and may be moderately to severely fragmented (Bird Life International 2012).
Effects of human activity on populations
Populations of Bay-capped Wren-Spinetail may be affected by habitat transformation mediated by drainage for agricultural development. Overgrazing certainly affects the Bay-capped Wren-Spinetail since it inhabits grasslands with extensive cover of grasses with low levels of cattle grazing (Isach and Cardoni 2011). In Buenos Aires Province, Argentina, sewage discharge seems to favor the abundance of Bay-capped Wren-Spinetails since it increases nutrient concentrations which in turns increases habitat structure (Cardoni et al 2011).