There’s a famous quote "never underestimate the bandwidth of a station wagon full of tapes bowling down a highway". Musing on this I decided to try and estimate the bandwidth of a carrier pigeon, given modern storage technology. According to Wikipedia, a racing pigeon can maintain about 50 miles an hour over moderate distances. So let’s feed our pigeon, strap a 64GB micro SD card to each leg, and send him from Bristol to London,which should take about 2 hours.
128GB in 2 hours is roughly 1GB/minute, or say 160 Mbps (megabits per second). That’s about the effective transfer rate for USB 2, and is getting on for Gigabit LAN speed. It’s about 50 times faster than the best I get from BT Broadband, and probably over 100 times faster than the sustained broadband bandwidth over a week, which is about how long 128GB would take to transfer. Plus remember that that’s the download speed, and upload is another factor of ten slower…
Now I would be the first to admit that there are some limitations to the "pigeon post" architecture, especially in terms of range. The latency also precludes chatty protocols. But in terms of sheer transfer bandwidth Yankee Doodle Pigeon has "broadband" beaten hands down!