旅行鸽和普通的鸽子非常相似。不过,它的后背是灰色的,似乎还有些发蓝,而胸前的颜色又是鲜红的,所以看上去是那么绚丽多彩。旅行鸽()好看,()数量繁多,曾经是地球上数量最多的鸟类之一。当它们组成庞大的队伍,唱着高昂响亮的歌儿,飞过北美洲上空时,鸟群遮住了阳光,地面上一片昏暗。有的 Traveling pigeons are very similar to ordinary pigeons. However, its back is gray, it seems that some blue, while the chest color is bright red, so it looks so colorful. Traveling pigeons () are good-looking, (a) numerous and once one of the largest birds on earth. As they formed a huge contingent of singing loud and loud songs that flew over North America, the birds covered the sun and the ground was dark. some