What is the airspeed velocity on an unladen swallow?

"Well, the most obvious answer- you might think- is “An African or European swallow?” But this is, indeed, where film culture begins to diverge from real life. Because in actual fact, none of the 47 swallow species found on the continent directly bears its name. We might consider the West African swallow, or the South African Cave swallow, however a choice between these two would be completely arbitrary- and neither is sufficiently studied to provide the data we need."

well, you are talking about 88 different species so you might want to be more specific

as far as I can google, swallows can reach speeds up to 32.4 km/h, which would be equivalent to 20 mph

Between 31 and 40 MPH         .

near 60 km per hour