BLACK-HEADED GROSBEAK
In central Mexico, where monarch butterflies and Black-headed Grosbeaks both spend the winter, the grosbeaks are one of the butterflies' few predators. Toxins in the monarch make them poisonous to most birds, but Black-headed Grosbeaks and a few others can eat them. They feed on monarchs in roughly 8-day cycles, apparently to give themselves time to eliminate the toxins. (Cornell)
Photographed on the Grand Mesa, Western Slope, Colorado.
BLACK-HEADED GROSBEAK
In central Mexico, where monarch butterflies and Black-headed Grosbeaks both spend the winter, the grosbeaks are one of the butterflies' few predators. Toxins in the monarch make them poisonous to most birds, but Black-headed Grosbeaks and a few others can eat them. They feed on monarchs in roughly 8-day cycles, apparently to give themselves time to eliminate the toxins. (Cornell)
Photographed on the Grand Mesa, Western Slope, Colorado.