If you spot a white flutter of tiny wings near a pine tree in the Tri-Cities this week, stop and take a closer look.

There is a good chance you're looking at a pine white butterfly, says Jim Dillman of Richland.

Pine trees are the homes of the distinctive butterfly, which has white wings with black veins. Females, which Dillman said are rare, have even more black and some red.

A few pine whites have been spotted in the Tri-Cities already this year, but this coming week is when they are most likely to be found, said Dillman, who has been studying butterflies as a hobby for more than 20 years.

He saw the pine white butterflies for the first time three years ago near a cluster of shady pine trees at the entrance to the Benton Franklin Fair & Rodeo.

Since then, Dillman, a retired architect, said he has found the butterflies in Benton, Franklin and Walla Walla counties.

One theory is that the butterflies, normally found in the pine forests of the Cascade and Blue mountains, were caught up in a thermal gust and deposited in the area about three years ago.

Now, Dillman said, Tri-Citians should continue to see them, although there may be some years where few, if any, are spotted. Butterfly populations fluctuate, but the reasons for that aren't completely know.

"There is a whole lot about butterflies that we don't know," he said.

The pine whites are only in their butterfly form for about a week before they die, Dillman said.

Unlike some other butterflies, pine whites flutter. Normally they are near the top of pine trees, but they do come closer to the ground to get nectar.

-- Kristi Pihl: 582-1512; kpihl@tricityherald.com