Monarch butterflies nectaring on Anacua tree blooms. San Antonio, Texas, USA on October 16, 2011. The Monarch migration is peaking for this year as the butterflies make their way towards the mountains near Mexico City. The record drought of the past several years has severely limited their food sources in Texas. The Anacua tree, known for the sandpaper roughness of its leaves, puts out sweet smelling blooms that provide vital nectar for the Monarchs.