Little Egret in North America: A Third Old World Colonizer

Every range expansion has a first chapter, and by the time anyone recognizes it, that chapter is usually long over. We know the Glossy Ibis and the Western Cattle-Egret as continental birds now, but their first North American records are dry lines in old journals, written by people who had no idea what they were looking at. The Little Egret is different. With this bird we are living inside chapter one. Somewhere on the Atlantic coast this year, a birder scanning a flock of Snowy Egrets will pick out one with gray lores and two thin plumes trailing from its head, and add another data point to a colonization still in progress.

An Old World heron arrives

Little Egret (Egretta garzetta) is one of the most familiar small herons of the Old World, standing in wetlands across Europe, Africa, and Asia. Like the Glossy Ibis and the Cattle Egret before it, it has begun to cross into the New World, and we can date the start with unusual precision. The first records came in 1954, in two places within weeks of each other: Barbados in April, and Flatrock, Newfoundland, in May, the latter a first for Canada and only the second for North America. Then, for a couple of decades, almost nothing. The bird reappeared in numbers in the 1980s and especially the 1990s, when records piled up across the West Indies, and in 1994 it did the thing that turns a vagrant into a colonist: it nested, on Barbados. Why an Old World heron should suddenly be probing a new continent is the question the whole cluster circles, and we take it up in Bird Vagrancy and Range Expansion Explained.

Up the seaboard

From that Caribbean foothold the Little Egret has pushed north, apparently traveling in company with Snowy Egrets returning up the Atlantic coast. Records now scatter from Suriname and Brazil in the south to Delaware, Massachusetts, Maine, New Brunswick, and Newfoundland in the north. The Maine bird that spent June 2011 at Scarborough Marsh, near the Audubon center, drew a steady stream of visitors, and Newfoundland has become the closest thing the species has to a North American stronghold, with something like fifteen records. It remains genuinely rare, an ABA Code 4 bird that shows up less than annually, but the trend line points the same way it did for the other two colonizers a century earlier: up.

Why every sighting counts

Here is the honest distinction that makes this bird worth the extra attention. The Glossy Ibis and the Western Cattle-Egret are settled North American breeders. The Little Egret is not. It has nested in the Caribbean, but on the mainland it remains a vagrant and, at most, an incipient colonizer, a bird that keeps arriving without yet staying to breed. That is precisely why each record matters, because taken together they are the raw data of a colonization we can still watch unfold, the same first decades the other two must have gone through unrecorded. There is some honest uncertainty about how a given bird got here, whether it crossed the Atlantic directly or worked its way north from Barbados, but either way it is a wild bird finding new ground under its own power, and eBird treats it as the rarity it is.

The bird hiding among the Snowys

The reason the Little Egret can colonize quietly is that it looks almost exactly like the Snowy Egret it travels with, and most that pass along the coast are surely never picked out at all. Separating the two is a real skill, resting on lores, plumes, and structure, and we lay it out in Little Egret vs Snowy Egret. Finding one in the first place, before it moves on, is its own challenge of alerts and timing that we cover in How to Find Rare Birds.

Chapter one

Set the three colonizers side by side and the Little Egret sits at the beginning of the road the others have already traveled. The Cattle Egret ran the whole arc fastest and has already crested and begun to fall. The Glossy Ibis arrived earlier, spread more slowly, and settled in. The Little Egret is only now doing what the Cattle Egret did in 1941, turning up as a rarity that a birder decades from now may look back on as the opening of something much larger. Whether it follows the same path, no one can say yet. But that is exactly what makes it worth watching, and worth looking twice at every white egret on the flat.