Developing best management practices for the invasive monk parakeet (Myiopsitta monachus) in urban environments

Managing invasive species has become a major environmental challenge due to their global ecological and socioeconomic impacts. Prioritising effective strategies is essential, especially given the often limited funding. Data from real control programmes are crucial for developing long-term management plans. Between May 2021 and April 2023, the City of Madrid implemented a control plan to reduce its monk parakeet (Myiopsitta monachus) population. This study assessed: (1) the plan’s efficacy, (2) the impact of removing different age classes on population viability, (3) the capture efficacy and cost-efficiency of various capture methods, (4) the optimal combination of capture methods and (5) the effectiveness of different baits in attracting parakeets. The plan eliminated approximately 87% of the juvenile and adult population present at the plan’s onset, reducing total population projections for 2023 and 2031 by 50%. Projections indicated that maintaining the second-year removal intensity for three additional years could have nearly eradicated the species. Removing juveniles and adults proved more than twice as effective at curbing population growth as targeting eggs and nestlings, leading to prioritising juvenile and adult removal year-round. Of the five methods used – shooting, folding net, hand-held net launcher, egg culling and nestling culling – shooting was the most effective in reducing population growth both in and outside spring. Optimisation models suggested prioritising shooting and the combination of folding net and net launcher in spring and exclusively the latter outside spring. We recommend using the shooting method year-round, complemented by the combined use of the folding net and net launcher outside of the spring season. Bread and a mixture of bread, apple and parrot feed were the most effective and cost-efficient baits attracting parakeets, with bread recommended for simplicity. This study enhances understanding of parrot management strategies, offering insights for more effective and cost-efficient control of invasive monk parakeet populations.