The factors affecting the olfaction-based navigational performances of homing pigeons released at relatively long distance (beyond 100 km from home) have in the past been subject to several investigations both in Germany and Italy using observations of vanishing bearing distributions. These studies highlighted the complexity of long-distance navigation in homing pigeons, which remains a poorly investigated aspect. In this tracking study we report how the homing performances of pigeons housed in Arnino (Pisa, Italy) were affected by the presence/absence of a mountain range (the Northern Apennines) interposed between the home and the release site area (release sites: Trans = mountain barrier, Cis = no mountain barrier). We displaced unmanipulated control pigeons, anosmic pigeon, and pigeons transported in purified air to release sites located at a distance ranging between 95 and 246 km from home. There, birds were released without further manipulation. The navigational performances of anosmic pigeons were impaired at both Cis and Trans sites compared to both smelling groups. Both unmanipulated control pigeons and pigeons transported in purified air but allowed to smell environmental air at both the release site and after release displayed unimpaired navigational abilities at the Cis site, but impaired homing success and impaired homeward orientation at the Trans sites. Nevertheless, their homeward component was significantly greater than that of the anosmic birds at both geographical areas. This suggests that the Northern Apennine acts as a geographical barrier affecting the olfactory map accuracy of Arnino pigeons, rather than totally reducing its spatial extent.

过去，在德国和意大利，通过对消失方位分布的观察，对影响相对较远距离（离家 100 公里以外）放飞的信鸽基于嗅觉的导航性能的因素进行了多次调查。这些研究强调了信鸽长距离导航的复杂性，这仍然是一个研究不足的方面。在这项跟踪研究中，我们报告了在阿尼诺（意大利比萨）饲养的鸽子的归巢性能如何受到介于家和释放地点区域之间的山脉（北亚平宁山脉）的存在/不存在的影响（释放地点：Trans = 山屏障，Cis = 无山屏障）。我们取代了不受控制的控制鸽子，无嗅鸽子，鸽子在净化空气中被运送到离家 95 至 246 公里的释放地点。在那里，鸟类在没有进一步操作的情况下被释放。与两个嗅觉组相比，嗅觉缺失的鸽子在顺式和反式位点的导航性能均受损。未经操纵的控制鸽子和在净化空气中运输但允许在释放地点和释放后闻到环境空气的鸽子都显示出在顺式站点的导航能力未受影响，但在跨站点的归巢成功和回家方向受损。尽管如此，它们的归巢成分明显大于两个地理区域的嗅觉缺失鸟类。这表明亚平宁北部是影响阿尼诺鸽嗅觉图准确性的地理障碍，