I'll admit and say that I am constantly amazed by the impact that rain has anywhere. In the Saguaro Desert, the seasonal rains cause the buds of the world's largest cactus to swell and then explode in bulky bouquets of (rather robust) white flowers. The Gila Woodpecker and Gilded Flicker are similar species in colour, behaviour, and even choice of habitat. While the cactus offers them refuge from the heat of the sun, these birds offer the intangible act of pollination. This is a relationship found between many plants and animals.