Here's the first thing pops up on Google, "They had to be transported manually before another flight. However, by placing their food at one location and their h

Here's the first thing pops up on Google, "They had to be transported manually before another flight. However, by placing their food at one location and their home at another location, pigeons have been trained to fly back and forth up to twice a day reliably, covering round-trip flights up to 160 km (100 mi)." And judging from other sources that's pretty credible.