It’s often assumed that pelicans consume small fish which they catch in their large, sac-like bills. But sometimes their catch is substantial. Biologists studying American White Pelicans at Idaho’s Minidoka National Wildlife Refuge last summer discovered an unusual fish tag expelled by a pelican on a small island. Two things made the tag out of the ordinary.
First, the tag was from Montana. Montana biologists identified it as belonging to a Brown Trout tagged in the Big Hole River. Evidently a pelican scooped up the trout in Montana and then flew 300 miles to Idaho. The fish was either digested along the way, or the tag lodged in the bird’s bill or digestive system and was expelled at a later time. Perhaps more notable was the fish’s size. At the time the brown trout was tagged, it weighed over two pounds and was 18 inches long. Pelicans, it seems, are happy to snag big trout.
Although anecdotal in nature, the discovery of the tag seems to lend some credibility to the theory that abundant white pelicans may hamper efforts to restore endangered arctic grayling on Montana’s Big Hole River. The Big Hole is home to a small population of river-dwelling grayling whose survival seems perpetually precarious. Some observers believe the large flocks of pelicans that frequent the river in drought years may be consuming significant numbers of the endangered grayling. If a pelican can chomp an 18 inch trout, it can certainly munch an adult grayling. I suppose a pelican can eat whatever it wants, but let’s hope those on the Big Hole stick with trout.