The last ones left just a few days ago, off on their perilous continent-long journey that is the marvel of the insect world. It took humans with their big brains thousands of years to learn how to use the position of the sun to orient themselves. Monarch butterflies, with just a tiny bunch of nerve endings, have been doing this for millennia, flitting from, well, my backyard to their winter resting grounds in a particular fir forest south of Mexico City, thousands of kilometres away. This has been an exceptional year for monarchs in Toronto and throughout northeast North America. Virtual clouds of the distinctive orange and black insects seemed to spring up from every little nectar-holding plot of land. It was not unusual to see half a dozen or so at a time fattening up on the flowers in our tiny garden. The return of the monarchs has been especially good news this year. Last year, Hurricane Katrina drowned probably hundreds of thousands as they winged their way south. Before that, there had been a couple of horrendous winters in Mexico where, by one estimate, as much as 80 per cent of the breeding stock was destroyed by storms. Toronto and its environs have been kind to monarchs. Official sanctuaries dot the shores along Lake Ontario, and Lake Erie to the south. What's more, there has been so much development in the surrounding areas that once-promising farm land has been left to pasture, allowing the proliferation of the milkweed that is the young monarch's essential first diet. As caterpillars, monarch larvae survive only on milkweed, a noxious plant that is banned in some provinces. Eating milkweed makes monarchs inedible to predators, who they thoughtfully alert to the danger with their vigorous orange and black markings. Monarchs are a huge mystery of the natural world, being the only insect to migrate any kind of distance. But how do they know where to go? No one has really answered that question yet. Resilient as they would appear, however, the migratory monarchs face an uncertain future. Illegal logging of the fir forests in Mexico is slowly destroying their winter habitat, while rampant pesticide use in the United States and Canada, not to mention suburban development, are also taking a toll. Still, in Toronto they are very welcome guests. They make their first appearance in late June, having made their way north from southern Florida and Texas. Having enjoyed the summer, they leave in late September or early October, some say when the sun dips to a certain height above the southern horizon. This year, it was just before the first snowfall. Maybe they knew it was coming.
