While studying Dippers Cinclus cinclus in northern Spain (see Galarza et al. 2023), we found two cases of egg-capping out of 343 broods checked (0.6% of the broods). Egg-capping is the attachment of the empty shell of a hatched egg to an unhatched one (Tinbergen 1963; Derrickson & Warkentin 1991). The hatched shell may slip over an unhatched egg forming a double shell layer causing the death of the embryo in the unhatched egg by interfering with gas exchange or making the hatching process difficult (Derrickson & Warkentin 1991).