Last week marked the 50th anniversary of the last documented sighting of the Eskimo Curlew. Everything considered, the species is extinct. And if any remain, they would be so difficult to find/see that extinction is the same.

The bird migrated through southwestern Minnesota on its way to the Arctic tundra for nesting and to the far end of South America when nesting ended. The curlew, one of eight species in its family, as numerous as any shorebird, made one of the longest roundtrip migrations of any bird species.

It disappeared for the usual reasons. When we had wiped out the Passenger Pigeon, that source of meat for market gone, hunters next chose Eskimo Curlews, one hunting party able to take thousands of curlews in a few days. As many as two million birds a year were killed annually, according to estimates.

At the same time, the portion of the birds' migration path through the United States was being plowed for crops. The prairies that provided the insects that fueled the final legs of migration disappeared.

The curlew could not survive that double whammy. The birds were gone about 20 years after the onslaught began. It doesn't take long if you ignore what you're doing.

A few Minnesota birders, not many, have in recent springs invested a day or two to drive the state's southwestern pastures and prairie remnants in search of migrating flocks of plovers. The curlew resembles a plover, if you take a casual look. These birders held thin hope that the curlew was not extinct, its small remaining numbers simply overlooked. They hoped to find the slimmer, slightly taller bird foraging with the plovers, evident to a sharpened eye.

The last confirmed sighting of Eskimo Curlew was in Texas in 1962. A year later – 50 years ago – a specimen was taken on Barbados. That was the end of the official story. Sighting of 23 Eskimo Curlews in Texas in 1981 was termed "reliable," no evidence presented. Ditto unconfirmed reports from Texas and Canada in 1987, Argentina in 1990, and in Nova Scotia as recently as 2006. Unconfirmed is the key word.

A wonderful book about this bird titled "Last of the Curlews" was published in 1954. Canadian author Fred Bosworth offered a fictional account of a year in the life of the bird. Over 3 million copies have been sold. I've read it. It's a good book, a sad story.

That makes three species of birds once seen in Minnesota and now extinct: the curlew, the Passenger Pigeon, and the Carolina Parakeet. The latter's range just nicked the southwestern edge of the state.

The drawing is from the late 1800s, artist unknown.