Please Step Forward and Identify Yourself?

Please Step Forward and Identify Yourself?

By Bill Willis

October 5, 2018

Is there a morsel in its throat?
Is there a morsel in its throat?
Photo courtesy of Bill Willis

On a peaceful summer day in 2018 a new bird was observed on Discovery Lake. The white bird displayed a certain grace and elegance as it made calculated steps in the shallows. With its neck outstretched and head extended, it would quickly plunge its beak below the surface of the water. A fish was often its reward.

The following avian account is true and substantiated by first hand sightings. Could employees see the same bird differently, but still agree? By the end of this discourse, there will be a better understanding of what was seen.

Discovery Lake has long hosted both Great Blue Herons and smaller Green Herons. In recent years, the Green Herons have nested twice and produced four young. There’s no evidence that the Great Blue has nested despite two adults being on campus. Therefore, is the new bird a Heron or not? The answer may not come easily.

NIEHS Great Blue Heron
NIEHS Great Blue Heron
Photo courtesy of Bill Willis
NIEHS Small Green Heron
NIEHS Small Green Heron
Photo courtesy of Bill Willis

Compare the Egrets and the Herons. Bear in mind that names can be localized and interchangeable and that there are sixty species globally.

Comparison of Herons and Egrets
Feature White Egret White Heron
Legs long, black, dark long, pale greyish yellow
Feet black black
Neck long long
Bills/Beaks harpoon-like, long orange-yellow harpoon-like, long, thick stout mostly yellow, with black
Plumes on head crest no, some young yes
Shoulder patch none dark blue
Size, relative smaller than Heron larger, heavier than Egret
Where found fresh and salt water lakes, ponds, swamps lakes, ponds, swamps
Breeding, Global Central and South America, Africa, Europe South America, Florida
Breeding, USA both coasts, north into Southern Canada Florida Panhandle only
Distribution, NIEHS (Birds EPA) yes no
Flocking heterogeneous with Herons solitary
Family Ardeidae Ardeidae
Genus Ardea and Egretta Ardea and Egretta
Color bright white can vary can vary, even dull white
Decorative plumes yes, breeding none
Swimming no no
Flying posture retracts neck on short flight retracts neck in flight
Food preferences carnivorous carnivorous
Diet fish, amphibians, reptiles, insects, crustaceans, small birds fish, amphibians, reptiles, insects, crustaceans, small birds

It turns out that the herons and egrets don’t have strong, distinctive and specific traits that would allow this group of birds to be distinguished apart. Immature, pre-breeding and mature bird plumage can falsely resemble other species, so the season and age must be a factor. Therefore, members of the family Ardeidae are often collectively called herons. Nesting range limits (Florida) may be key.

Conclusion

Having compared our visitor with published articles, we conclude that our mystery bird is a Great White Egret rather than the locally much rarer Great White Heron. The very white plumage, yellow bill, black legs, rarity of the Great White Heron north of Florida, and smaller size compared to the Great Blue Heron, supports this identity of Great White Egret/Heron.

The author would like to acknowledge the research assistance provided by Nora Weston, Access Services Librarian.

Give It A Try: How Many "Heron Species" Can You Find in These Images?

Four heron species in flight: Great Egret (left); Snowy Egret (lower middle); Little Blue Heron (lower right); Cattle Egret (upper right, and trio of smaller birds)
Four heron species in flight: Great Egret (left); Snowy Egret (lower middle); Little Blue Heron (lower right); Cattle Egret (upper right, and trio of smaller birds). The same structural and bill/leg color differences generally apply to these species whether they are in flight or perched. Note Great Egret’s larger size and longer legs and note Cattle Egret’s compact overall structure.
Photo courtesy of Composite; photos by George Armistead and Brian Sullivan
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