Great Egret

Late summer typically sees an influx of wading birds into New Hampshire from breeding areas to the south, with individuals showing up in areas where they are not known to breed. No species illustrates this better than the Great Egret. Starting in July, large numbers of egrets disperse from nesting colonies, resulting in a dramatic increase in numbers along the coast. This same phenomenon occurs inland, where it starts a little later and has a much lower magnitude. The numbers of dispersing birds vary among years, probably depending on some combination of breeding success and foraging habitat. In years of drought for example, egrets are more likely to wander farther in search of suitable feeding areas.

These large late summer incursions of egrets are a relatively recent phenomenon, since like other wading birds they were indiscriminately hunted for their plumes until the early 1900s – so much so that the entire U.S. population was estimated at 3000 in 1910. Increased protections, including of nesting sites, allowed populations to recover dramatically and a century later experts estimate there are now 180,000. As part of this recovery, Great Egrets gradually expanded northward along the Atlantic coast, and now breed well into Maine, as well as inland in the Great Lakes. The nearest colony to New Hampshire is on Appledore Island in the Isles of Shoals, which the species (and other herons) recolonized in the early 2000s when the human presence was much reduced due to COVID-19.

Globally, the Great Egret is one of only a few truly “cosmopolitan” birds, meaning it nests on every continent except Antarctica. It is clearly a highly adaptable bird, possibly because it’s able to breed and forage in a wide range of habitats. This adaptability has certainly aided in its recovery, to the extent that very few significant threats have been identified. As top predators in aquatic systems, egrets may be impacted by consumption of chemical contaminants (e.g., mercury, pesticides, etc.), although there are limited data on this potential threat. Thankfully the data we do have are not terribly concerning, and most colonies are in hard-to-reach places, so the future of Great Egrets along our coast (and increasingly inland) appears secure.