White is a beautiful color. It’s bright and showy, and therein lies the problem.
In nature, brazenness like “bright and showy” is usually dealt with harshly. If you're potential prey, white is a predator magnet. If you're a predator, bright and showy can mean an empty stomach, because potential prey can stay safely out of your way.
Yet, there is a visitor in the valley that is immaculate white — the great egret.
Every summer about July, great egrets begin to appear along the shores of lakes, streams and especially farm ponds of the Rogue Valley. They stalk mosquitofish, young bluegills, frogs, crayfish and other delectable items. They are never abundant, but they are impossible to miss.
Why white? Many close relatives such as bitterns are the very poster children for camouflage. None do it better. So why don’t egrets hide like their cousins?
There are birds that do “brazen” things. Males of many species sing, wear head plumes, dance or don dazzling breeding plumage, but it’s usually just the males. The risk of drawing a predator’s attention is offset by the need to find a mate. But if white is sexy, why aren’t male egrets white and females a more somber color? Bright males and cryptic females. This works for many birds, such as mallards and tanagers, and even these males lose the bright colors outside the breeding season. All white all the time just doesn’t make sense. It seems to break all the rules for survival.
Before 1960, egrets rarely occurred west of the Cascades. A big reason was the plume trade. Women’s fashion around the turn of the 20th century dictated that hats must be adorned with the feathers of birds, and market hunters were eager to cash in.
Egrets nest colonially in trees, making them easy targets. These breeding aggregations are often called rookeries, named for the rooks of Europe, a crow-like bird that also nests colonially in trees. For egrets, a more appropriate term is “heronries.”
In Oregon at this time, they were found only in the marshes from Upper Klamath Lake east to Malheur Lake. Egrets nesting along the Silvies River draining into Malheur Lake once numbered well over 300 pairs, but this was reduced to only two pairs by 1908. The published account of the slaughter on the Silvies was instrumental in the movement to protect these birds, resulting in both the Audubon Society and laws restricting the taking of these birds. Since then, numbers have recovered.
Each summer great egrets disperse from their breeding areas, with small numbers drifting into our area. Agate Lake is perhaps the most dependable place to see these birds. Numbers peak in the fall before individuals begin to make their way back to the breeding colonies. Most head for the Central Valley and coast of California.
A very few individuals remain with us year round, probably immature birds. Someday I predict we will find one or two pairs breeding alongside the great blue herons in one of the heronries along the Rogue or Applegate Rivers.
So enjoy the fall visitor, and if you have any insights about how a bright, white bird can survive in a world where concealment is usually a requirement for survival, please let me know.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached at firstname.lastname@example.org.