<i>Melanerpes cactorum</i> (White-fronted Woodpecker) selects exotic trees with low wood density for cavity excavation in a Neotropical city

Abstract Urbanization alters ecological resources used by cavity-nesting communities, often reducing excavation substrates, such as standing deadwood for safety or aesthetic purposes. We examined tree selection for cavity excavation by Melanerpes cactorum (White-fronted Woodpecker) in urban parks of Córdoba, Argentina, a temperate Neotropical city. Across 279 ha in 89 parks, we located 49 excavated trees and compared their attributes with paired control trees. Using generalized linear mixed models, we assessed the effects of wood density, decay class, diameter at breast height, tree height, canopy cover, and local tree density on tree selection. Substrate hardness, determined by wood density and decay, strongly shaped excavation patterns. Woodpeckers predominantly excavated live trees with low wood density, especially the exotic Chinaberry (Melia azedarach), which represented nearly 80% of excavated trees despite comprising only 4% of available trees. Melanerpes cactorum selected live trees only in the case of species with low wood density, whereas higher wood-density species were increasingly chosen as decay advanced. Current urban management may filter out deadwood-dependent bird species, but exotic trees with soft wood even when alive may help satisfy the ecological requirements of woodpeckers. In the short term, management strategies should selectively retain deadwood in low recreational-use spaces and include tree species within a suitable hardness range when living, enhancing diversity and resilience in urban cavity-nesting communities.