Hybridization occurs in only one genus of Shrikes, Lanius.
In Western Siberia, Red-backed Shrike (L. collurio) and Brown Shrike (L. cristatus) interbreed and produce fertile offspring (Kryukov & Gureev, 1997).
And in North America, two subspecies of Loggerhead Shrike (L. ludovicianus migrans and L. l. excubitorides) hybridize along a contact zone (Vallianatos, Lougheed & Boag, 2001).
References
Kryukov, A. & Gureev, S. (1997). New data on interrelations of red-backed and brown shrikes (Lanius collurio and L. cristatus, Aves) in zone of sympatry. Zoologicheskii zhurnal 76, 1193-1201.
Vallianatos, M., Lougheed, S. C. & Boag, P. T. (2001). Phylogeography and genetic characteristics of a putative secondary-contact zone of the loggerhead shrike in central and eastern North America. Canadian Journal of Zoology-Revue Canadienne De Zoologie 79, 2221-2227.