[["Hummingbirds hum because their wings are moving so fast that it is causing the air around them to vibrate. ", 31.0], ["Humming birds do not intentionally hum.  The hum comes from the extreme speed of the flapping of their wings to stay aloft.\n", 16.0], ["Hummingbirds do not hum.  The sound that is heard is caused by the very rapid beating of their wings, which allows them to hover in the air while they collect nectar from flowers.", 9.0], ["They hum is because they've got a pair of tiny wings that are whipping back and forth forty times every second.", 6.0], ["Potential mates ", 0.0]]
do you know why hummingbirds humm
animals,hummingbirds,ostriches