Evaluating the impacts of law enforcement and market outreach campaigns on the Indonesian caged bird trade in Kalimantan

Abstract Indonesia is the epicentre of the Asian songbird crisis, yet few studies test whether enforcement and outreach can curb trade. We evaluated a combined market-outreach and law-enforcement program targeting caged birds in West Kalimantan.We compiled 2014–2025 data from annual surveys of 374 bird shops and 2019–2025 Facebook sales data from thousands of seller accounts. Temporal changes in bird abundance were analysed using negative binomial and logistic mixed models. In physical markets, sales of protected species declined by 40–59 percent relative to pre-intervention levels, and the share of shops selling protected species fell from 88.7 to 21.6 percent. Using a dose-response model, districts with more arrests showed progressively fewer birds per shop, with especially strong declines in protected species. Online, protected species per post and per seller account declined by 5–8 percent per year, while non-protected species remained broadly stable. These results show that trader outreach coupled with consistent enforcement can sharply suppress open trade in protected songbirds. The intervention appears to shift markets toward non-protected taxa rather than simply displacing trade to new venues. Our findings provide rare quantitative evidence that entrenched wildlife trades respond to targeted interventions and offer a scalable model for reducing illegal bird trade in Indonesia.