As bird flu spreads to dairy cows, Minnesota's raptors show signs of building remarkable immunity

A little barred owl looked up from the crux of Dana Franzen-Klein's elbow, stared the veterinarian in the eye and, in as tough and menacing of a posture as he could muster, clicked his beak. The injured bird was a baby, maybe a month old. His click was a warning, that despite being a puffball barely bigger than Franzen-Klein's palm, he would bite the medical director of the Minnesota Raptor Center if he had to.