When you hear a report of a unexpected animal or bird showing up someplace, is it because they really moving into new places? Or did we just become better spotters? Or maybe it was the biological authorities who became less dismissive of citizen scientists? That was the gist of what ornithologist Shibail Mitra mulled over at a lecture at the Linnean Society of New York last night.

Mitra, who a biology professor at the College of Staten Island, came down for the citizen scientists, showing through several bird species examples how official guides willfully overlooked several species–counting them as an unremarkable subspecies, invasive escaped pets or just rare lost souls. Then when a committee somewhere declared it was a legitimate species, people started reporting more of them.

Barnacle Goose Branta leucopsis

Courtesy of Ucumari

This bird breeds in Greenland, so its appearances early in the 20th Century were written off as escaped pets. Serious birders would put parentheses around them on their lists because they didn’t really count. Now they’re showing up more than once a year and records counters are accepting them.

Cackling Goose Branta hutchinsii

The Cackling Goose was dismissed as a a subspecies of the Canada Goose. So nobody counted it and it was “grossly overlooked,” Mitra says. Then in 2004 the American Ornithology Union decided that this much smaller bird that breeds in the arctic and winters in the west from Oregon to Mexico really is a separate species. That manmade distinction always makes the

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