Feral Pigeons: Problems, Dynamics and Control Methods

Abstract

Feral pigeons are birds now largely present with naturalized populations all around the world (Lever, 1987). The Rock Dove (Columba livia), which is their ultimate ancestor, was originally present in coastal and inland cliffs of central and western Palearctic and in the northern Ethiopian regions, as well as in those of the Indian subcontinent (Goodwin, 1983). These wild populations gave rise to domestic breeds as a result of artificial selection, having been the pigeons one of the first birds subjected to domestication (Sossinka, 1982). Domestics readily go feral, they have done so widely and in different times and locations', both in their natural range and in all continents where they were transported as captive birds, and subsequently introduced (Johnston & Janiga, 1995; Lever, 1987). Pigeons are granivorous birds tightly linked to arid and rocky habitats, so that feral populations remain linked to human settlements both as a consequence of their domestic origin and by these biological characteristics, that act in synergy (Baldaccini, 1996a). According to Goodwin (1978) the synanthropism of ferals is mainly a consequence of the food resources becoming available with the development of agriculture or otherwise mainly depends on the presence of buildings that constitute a vicariant habitat with respect to the natural one, as suggested by Hoffmann (1982). Food resources and human buildings are the key ecological factors that bring ferals into most cities and towns worldwide (Haag-Wackernagel, 1995), extensively in agricultural habitats and wherever man has constructed suitable recoveries to dwell in, forming stable or increasing populations of millions of individuals as stated by BirdLife International (2004) for Europe or Sauer et al. (2008) for the USA. The way by which feral pigeons established in urban habitats has been illustrated from a historical point of view by Ghigi (1950) and van der Linden (1950) and recently reviewed by Johnston & Janiga (1995), Haag-Wackernagel (1998) and Baldaccini & Giunchi (2006). Even in the Old World, synanthropic wild Rock Doves have a very marginal contribution to the constitution of feral populations (Ballarini et al., 1989; Johnston & Janiga, 1995).