I have been living in Burlington, CT, for almost 35 years. That's 35 years without seeing a monarch caterpillar. Even after I started planting milkweed in my "lawn" about 10 years ago. But this year I have 2 large cats munching away, putting on weight, and if I am lucky becoming the next generation of butterflies!
1. Too many farms have been abandoned and grown up to forests.
2. Too many of the old fields have been converted to cookie-cutter housing developments.
3. Most of the plants that native butterflies feed on are considered “weeds” by the companies that sell monocultured grass carpets and have chemicals that can kill everything that is not grass.
4. Even my neighbors who have joined the trend of planting butterfly gardens have been treating their property with insecticides. They bring in the butterflies and then poison them.
Still, there are two fat cats in my yard, and maybe they will survive the trip to Mexico, overwinter there, and return in the spring.