One of the first bug events in the spring that gets trout looking up for their food. Watch for Hendrickson mayflies beginning to emerge early in May. Expect spinner falls to begin during the first few days of may depending on the weather. Hendrickson action should last until late May or even early June depending on where you fish in Ontario. After a long winter hunkered down eating nymphs and minnows, trout are always willing to sip a few of these bugs from the surface as they emerge.