More probable is bird transport ,either externally,by accidental attachment of the seeds to feathers,or internally,by the swallowing of fruit and subsequent excretion of the seeds.
更有可能的是鸟类运输或者是通过外部途径，即由于种籽偶然粘附在羽毛上;或者是通过内部方式，即由于鸟类吞食果子并随后将种籽排泄出来。
难句类型：复杂修饰、插入语、倒装
难点解析：句首有一个倒装，正常语序是bird transport is more probable。后面的句子中由于插入部分的频繁出现使句子显得十分凌乱。
结构划分：More probable is bird transport,/either externally,/by accidental attachment of the seeds to feathers,/or internally,/by the swallowing /of fruit and subsequent excretion of the seeds.