“Never underestimate the bandwidth of a station wagon full of tapes going down the highway.” -Andrew Tanenbaum

... or a carrier pidgeon with an SD card, it would seem :-)

But if you lose that carrier pigeon to zombie crows, you lose the SD cards. No factory to make new ones. The risk/reward ratio would be intolerable.

What is the symbol rate of an sd laden carrier pigeon?

African or European?

Well, you have to know these things when you're a king, you know.

SD cards are tiny. Probably 20 or 30TB.

This seems to check out. Given 1TB micro SD cards, a card weight of 2.55 grams each, a carrier pigeon being able to hold 75 grams, and the unrealistic but good enough assumption of no further weight being carried (e.g. tape or something else to keep everything from falling off the pigeon), we get 75 / 2.55 = 29.4117647059 (or 29 even taking the floor, since it doesn't make much sense for a pigeon to carry a partial card).

All these numbers are from google summaries, without further source checking.

Yeah but during zombie apocalypse you don't know what else that pigeon might be carrying.

Also your TB sized packet might get lost, or eaten.

Couriers are more reliable, though still not perfect.