Behav Ecol Sociobiol (2006) 59: 397–402 DOI 10.1007/s00265-005-0063-2 ORIGINAL ARTICLE Paulo Jorge . Luis Vicente Loft features influence the processing of navigational information by pigeons Received: 17 January 2005 / Revised: 7 July 2005 / Accepted: 8 July 2005 / Published online: 11 October 2005 # Springer-Verlag 2005 Abstract The present study evaluates the impact of lofts on the development of the navigational system of pigeons. A series of results obtained between 2000 and 2004 were analyzed. The H-loft was placed 10 m above the ground, with a ring format and seven windows all around it as well as three external aviaries that allowed birds to have a wide view of the outdoors and of the sky and knowledge of the wind dynamics. The L-loft was placed at ground level, with a single window transformed into an external aviary. The L-loft was protected from the wind by surrounding trees, reducing the ability of the pigeons to access the wind dy- namics and also restricting their access to information regarding the outside area and the sky. In a preliminary analysis, we found the parameter of “vanishing time” to differ significantly between lofts in two of the five age classes. A thorough analysis of this parameter throughout the ontogenetic development of the birds demonstrated a pronounced improvement in the information-processing system with age, with adults vanishing quicker than younger birds, although an impairment of development occurred during the third month of age, perhaps due to a reorganization of the system. This result was obtained when the effect of lofts was considered in the different age classes. Results suggest that loft features are an im- portant factor in the ability of the young pigeons to exploit navigational cues. Keywords Loft feature . Information-processing system . Navigational “map” improvement . Multi-cue . Homing pigeon Introduction Contradictory results have been obtained in studies of the navigational mechanisms of the homing pigeon (Papi 2001; Wiltschko and Wiltschko 2003; Wallraff 2004), leading to the suggestion that pigeons may be able to operate with a variety of cues. Consequently, an ontogenetic model that includes either a change of strategy (Wiltschko and Wiltschko 2003) or that considers developing an early strategy to enable continuous improvements (Papi 2001; Wallraff 2004) comprises a learning process that is essential for the es- tablishment of the navigational system. Thus, it is reason- able to expect that the development of the navigational system can be influenced by the environmental conditions experienced by pigeons when inside the loft or in the vicinity of the loft and by the way that birds ranked the navigational information available (Schmidt-Koenig 1963; Wiltschko et al. 1987, 1989; Walcott and Brown 1989; Walcott 1992, 1996; Braithwaite and Newman 1994; Braithwaite and Guilford 1995; Jorge and Vicente, in press). Such facts lead us to highlighting the importance of lofts as being one of the main tools for assessing how pigeons develop their nav- igational system. Nevertheless, the importance of loft features as a cause of variability in navigational development has been neglected over the years, even though some experiments had indicated its importance. Schmidt-Koenig (1963) suggested that the orientation of pigeons at the same site probably differed due to loft location. Wiltschko et al. (1987) and Wiltschko et al. (1989) observed that the significance of olfactory informa- tion in initial orientation development depended on the loft exposure to wind during the pigeon’ s early life. Moreover, Walcott and Brown (1989) and Walcott (1992) pointed to the fact that pigeons that have been raised in lofts that were only a few kilometers apart had different responses when re- leased at magnetic anomalies, even when the sun was visible. Similarly, Braithwaite and Newman (1994) and Braithwaite and Guilford (1995) found a relationship be- tween pigeon exposure to the surrounding landscape of the loft during development and the visual landmarks that exist in the homing mechanism of adult pigeons. Recently, Jorge Communicated by W. Wiltschko P. Jorge (*) . L. Vicente Departamento de Biologia Animal, Centro de Biologia Ambiental–FCUL, Rua Ernesto Vasconcelos, Bloco C2, 3° Piso, 1749-016 Lisboa, Portugal e-mail: pajorge@fc.ul.pt Tel.: +351-21-7500000 Fax: +351-21-7500169