Grebe hybrids are rare. Some crosses have been describes, such as Hooded Grebe (P. gallardoi) x Silver Grebe (P. occipitalis)(Storer, 1982) and Western Grebe (Aechmophorus occidentalis) x Clark’s Grebe (A. clarkia)(Konter, 2009) The numbers of the latter hybrid are increasing in at least two populations (Konter, 2011; Konter, 2012).
On Madagascar there appears to have been extensive hybridization between the endemic (and now extinct) Alaotra Grebe (Tachybaptus rufolavatus) and Little Grebe (T. ruficollis) (Voous & Payne, 1965).
Konter, A. (2009). Occurrence of Clark’s Grebes and their hybrids with Western Grebes in Prairie Canada. Blue Jay 67, 26-33.
Konter, A. (2011). Interbreeding of Aechmophorus Grebes. Wilson Journal of Ornithology 123, 132-136.
Konter, A. (2012). Visual Assessment of Interbreeding by Aechmophorus Grebes. Wilson Journal of Ornithology 124, 713-720.
Storer, R. W. (1982). A Hybrid between the Hooded and Silver Grebes (Podiceps gallardoi and P. occipitalis). The Auk, 168-169.
Voous, K. & Payne, B. G. (1965). The grebes of Madagascar. Ardea 53, 9-31.