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" jumps " over which they are trained are often much greater than the limits of visibility. For example, pigeons trained to race to this country from Western France are often jumped over 150 miles of unknown country in France as first stage in the journey, yet at an altitude of 3000 feet, even the horizon, which is the limit of visibility, is only about 60 miles distant. In addition, pigeons have been released at sea with no previous training, 125 miles from land, and got back to their lofts. It seems, therefore, that homing pigeons possess a faculty which gives them a sense of direction towards home, and that they make use of visual cues to tell them when they are getting near to it. Turning now to wild birds, we find the same thing holds, except that the faculty of orientation is probably much better developed in wild birds than it is in the domesticated pigeon, whose domesticity and training may have blunted some of the natural instinct, replacing it by speed and endurance of flight, arid greater reliance on visual cues. Many experiments have now been carried out, on all manner of wild birds, to test their ability to get back home after removal for varying distances. In America, some noddy terns and sooty terns nesting on islands in the Gulf of Mexico were taken by ship 850 miles over the ocean to an area which these species do not normally inhabit, and there released. Many found their way back. Here there can be no question of landmarks guiding the birds, at least until they are almost home. Other experiments have been conducted in this country on sea-birds, namely on the puffin, storm-petrel and Manx shearwater. Puffins released at Start; Point, returned to Skokholm Island, Pembrokeshire, a distance of 125 miles direct or 220 miles by shortest sea route, in 5 days. Storm-petrels, released from the same place, returned in 6 days, whilst other storm-petrels, released on the Isle of May (Firth of Forth), which was 340 miles direct (involving a land crossing of north Britain) or 800 miles by shortest sea route from Skokholm, returned in 11 days. Shearwaters, birds which never normally come to land except to breed, exhibited remarkable ability to " home," even over land areas. One released at Birmingham, 90 miles from the nearest sea and 160 miles from home, got back safely ; another released inland at Frensham, Surrey, got |
