The PCs traveling along the road/path/trail begin to hear a low droning sound. As they approach they find their path obstructed by hundred of thousands of droning insects. Locusts swarm though the air, feasting on the grass and plants. Passage will be slowed, but the insects pose no threat to the party, aside from being crunchy and disgusting underfoot, climbing into pouches and eating exposed food goods.
Whistling on the sea is bad luck. It is said to mock the sound of a strong wind and will call it so nature can show the true sound. Whistling is only allowed when becalmed or when shrouded in fog.