The Collaborative International Dictionary of English v.0.48:
butcher bird \butcher bird\, butcher-bird \butcher-bird\,
1. (Zool.) any species of shrike of the genus Lanius, so
called because they impale their prey on thorns.
[1913 Webster + WordNet 1.5]
2. (Zool.) large carnivorous Australian bird with the
shrikelike habit of impaling prey on thorns.
Note: The Lanius excubitor is the common butcher bird of
Europe. In England, the bearded tit is sometimes called
the lesser butcher bird. The American species are
Lanius borealis, or northern butcher bird, and
Lanius Ludovicianus or loggerhead shrike. The name
butcher bird is derived from its habit of suspending
its prey impaled upon thorns, after killing it.