## 5 Conclusions
Scene intercalibration was performed by computing a major axis regression on the area of the image where the two scenes coincide and rescaling one of the scenes to the range of values of the reference scene (see methods). Figure S2. Map with the temporal variability (standard deviation) of the Normalized Difference Water Index (NDWI) used to extract the intertidal region in our study area. The threshold used to identify the intertidal region was 0.2. Figure S3. Pearson's correlation matrix between all considered predictors. \"X\" signals non-significant correlations (for a 95% confidence interval). Figure S4. Histogram of mud content (% of sediment with grain size < 63 um), coloured by sediment types according to [2], adapted from [PERSON] et al., (1970). Figure S5. Map of the digital elevation model of the intertidal areas of the Bijagos Archipelago, with measures of the intertidal extent of natural geographic units within the study area. Figure S6. Mean reflectance values of the 14 best predictors used to classify seven intertidal habitat types of relevance to migratory shorebirds in the Bijagos Archipelago, Guinea-Bissau. Conceptualization, M.H., J.P.G., T.C., J.R.B. and T.P. ; data curation, M.H. and J.R.B. ; formal analysis, M.H., J.R.B. and J.P.G. ; funding acquisition, T.C., J.P.G., T.P. and S.P. ; investigation, M.H., J.R.B., J.P.G., T.C. and T.P. ; methodology, M.H., J.R.B., J.P.G. and T.C. ; project administration, T.C., S.P. and J.P.G. ; resources, T.C., J.P.G., S.P. and T.P. ; supervision, J.P.G., T.C. and T.P. ; visualization, M.H., J.R.B., J.P.G., T.C. and T.P. ; writing--original draft, M.H. ; writing--review and editing, T.C., J.R.B., T.P., J.P.G. and S.P. All authors have read and agreed to the published version of the manuscript. This work was supported by the MAVA Foundation through the project \"Waders of the Bijagos: Securing the ecological integrity of the Bijagos Archipelago as a key site for waders along the East Atlantic Flyway\". Fundacao para a Ciencia e Tecnologia (FCT Portugal) provided additional financial support to CESAM (UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020) and through the project \"MigraWebs: Migrants as a seasonal ecological force shaping communities and ecosystem functions in temperate and tropical coastal wetlands\" (PTDC/BIA/ECO/28205/2017). M.H. and T.C. were supported by FCT through doctoral grants (SFRH/BD/131148/2017 and COVID/BD/151924/2021) and contract (2021.00573.CEECIND), respectively. Data Availability Statement: Data supporting the reported results can be made available upon reasonable request by contacting the authors directly. Thanks are due to the Instituto da Biodiversidade e das Areas Protegidas Dr. [PERSON] (Guinea-Bissau), namely to [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON], and to Tiniguena-Esta Terra e Nossa, namely [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] for providing the permissions and logistical support needed during field work. We also thank all collaborators that helped us during this work, namely [PERSON], [PERSON], [PERSON], and [PERSON] for critical help in the field. We thank MARE/FCUL, namely [PERSON] and [PERSON], for advice and for granting access to the sediment analysis laboratory. We are grateful to [PERSON], [PERSON], [PERSON] and [PERSON] for providing support during our stay on the field. Finally, we thank [PERSON], [PERSON], [PERSON], and [PERSON] for valuable advice on remote sensing subjects. The authors report there are no conflict of interest to declare.