Black-headed Grosbeak
Pheucticus melanocephalus

f6.3 @ 1/640s, ISO:640, Nikon D3S w 500mm


"Black-headed Grosbeak," Wikipedia, the free encyclopedia. The black-headed grosbeak eats pine and other seeds, berries, insects and spiders, and fruit. During the summer, it mostly eats spiders, snails, and insects. It is one of the few birds, along with the black-backed oriole, that can safely eat the poisonous monarch butterfly. In their wintering grounds, this grosbeak consumes many monarch butterflies, perhaps over one million per year in the overwintering colonies in Mexico. However, only the black-headed grosbeak is physiologically insensitive to the cardiac glycoside heart poisons in the monarchs, which the monarch sequesters from its milkweed host plants. The same genetic changes that confer resistance to the poisons in the monarch and its relatives were found to have evolved in the black-headed grosbeak in a case of convergent evolution.
Madera Canyon, Green Valley, Arizona
 
04/26/2018