The genus
Columba is the largest within the
pigeon family, and has the widest distribution. Its members are typically pale grey or brown, often with white head or neck markings or iridescent green or purple patches on the neck and breast. The neck feathers may be stiffened and aligned to form grooves. One of several subgroups within
Columba consists of the widespread Eurasian common wood pigeon, Bolle's pigeon, the trocaz pigeon, and the African
Afep pigeon. Two
Macaronesian endemic pigeons, Bolle's and trocaz, are thought to be derived from isolated island populations of
C. palumbus. The Atlantic archipelagos of the
Canary Islands, Azores, and
Madeira have a volcanic origin and have never been part of a continent. At various times in the past, the major islands of these archipelagos were all colonised by ancestral wood pigeons, which evolved on their respective islands in isolation from the mainland populations. One of these was the lineage of extinct species
laurel forest mountain pigeon or Azores black pigeon ().
Mitochondrial and
nuclear DNA sequences suggest that the ancestor of
Bolle's pigeon may have arrived in the Canary Islands about 5
mya. An older lineage gave rise to another Canarian endemic, the
laurel pigeon,
C. junoniae, may date from 20 mya. The
trocaz pigeon was recognised as a different species from the other local form, the now-extinct
Madeiran wood pigeon, the two local pigeons never interbred or habitually associated together. The trocaz pigeon is a
monotypic species, although in the past Bolle's pigeon was sometimes regarded as a
subspecies of the trocaz pigeon. The most recent common wood pigeon arrival came from a European or African subspecies, giving rise to the subspecies
C. p. maderensis, on Madeira and
C. p. azorica in the Azores islands. ==References==