Europe's highest densities of breeding Mallards ( Anas platyrhynchos ) are found in the Netherlands, but the breeding population there has declined by ~30% since the 1990s. The exact cause of this decline has remained unclear. Here, we used an integrated population model to jointly analyze Mallard population survey, nest survey, duckling survival and band-recovery data. We used this approach to holistically estimate all relevant vital rates, including duckling survival rates for years for which no explicit data were available. Mean vital rate estimates were high for nest success (0.38 ±0.01) and egg hatch rate (0.96 ±0.001), but relatively low for clutch size (8.2 ±0.05) compared to populations in other regions. Estimates for duckling survival rate for the three years for which explicit data were available were low (0.16-0.27) compared to historical observations, but were comparable to rates reported for other regions with declining populations. Finally, mean survival rate was low for ducklings (0.18 ±0.02), ... : Funding provided by: Vogelbescherming Nederland Crossref Funder Registry ID: http://dx.doi.org/10.13039/100018722 Award Number: Funding provided by: Jaap van Duijn Vogelfonds* Crossref Funder Registry ID: Award Number: Funding provided by: Stichting Betty Wiegman fonds* Crossref Funder Registry ID: Award Number: Funding provided by: Dutch Centre for Field Ornithology* Crossref Funder Registry ID: Award Number: ...