Challenges, pitfalls, and potential solutions in assessing status and trends of Spheniscus penguins

Reliable, up-to-date assessments of population status and trends are essential for effective conservation. For the four Spheniscus penguin species, these are often undermined by methodological and logistical constraints due to their unique breeding ecology (e.g., burrow nesting and asynchronous breeding). As a result, no single survey method is universally applicable across the genus. Moreover, uneven sampling effort, inconsistent survey protocols, and variable data quality across countries and research groups further obscure true demographic patterns and complicate interpretations across species and regions. In consequence, population trends for these species—among the world's most threatened seabirds—are frequently uncertain or contradictory, limiting our ability to propose effective management actions. Here, we summarize the current challenges faced by researchers working across the ranges of Humboldt, African, Magellanic, and Galápagos penguins. We discuss pitfalls associated with extrapolating from non-representative colonies, integrating disparate data types, and interpreting trends in the context of climate-driven variability and threats. Finally, we propose a suite of solutions to strengthen future assessments and improve consistency and accuracy. Overall, we aim to chart a collaborative path toward more robust, comparable, and effective conservation assessments for these penguins as well as other seabirds.