Providing interpretive education on wetlands and wildlife, panoramic views, water quality, weather, natural resource management, trails, bird watching, recreation, exhibits, displays and an eagles nest, Jackson Bottom Wetlands Preserve is a treasure of the Hillsboro community.
Most people have seen the adult form of a dragonfly or damselfly, but few stop to consider that this is just a brief stage in its life cycle. The adult phase of a dragonfly consists of a few short weeks when it feeds and mates.
To mate, the male grasps the female behind the head and then the female brings its abdomen forward to collect sperm from the male. It is very surprising to see how well the pair can fly when paired like this.
Vivid Dancer (Argia vivida) mating pair
Paddle-tailed Darner (Aeshna palmata) mating pair
After the female collects sperm from the male, she deposits fertilized eggs in a pond or slow stream. These eggs will eventually hatch into an aquatic nymph that feeds on other aquatic insects.
Eventually the nymph crawls out of the water, splits its skin, and the adult form emerges. The fresh adult must inflate its wings and allow its skin begin to harden before it can fly.
Clubtail nymph ready to leave the stream.
Clubtail adult preparing to fly after emerging from its nymph skin.
Although strong fliers, most dragonfly species mate and die within relative close proximity to the pond from which they hatched.
A dragonfly has incredible multifaceted eyes that can detect movement in almost any direction. This is essential for detecting prey—and for avoiding another larger dragonfly that might try to capture it. The only way to get close enough to view a dragonfly is to move very slowly and steadily.
Closeup of the eyes of a Paddle-tailed Darner.
Binoculars are very helpful to a better view of a dragonfly. Ideally you will want to have binoculars that are close focusing (examples include the Pentax Papilio, the Nikon Monarch, and Eagle Optics Ranger). You can find several useful reviews of close focus binoculars online.
Summer months are the best time to view dragonflies. A few species can be seen in the spring and well into fall but summer offers the greatest variety.
Although dragonflies can be found almost anywhere, they tend to congregate near water to feed and mate. Any pond or lake with bordering vegetation is liable to have at least some dragonflies. A few species prefer slow streams rather than still water.
Dragonflies and Damselflies of the Willamette Valley Gordon, S. & Karst, C. (2005, CraneDance Publications). The authors wrote this as a fund raiser for the West Eugene Wetlands. This 110 page guide covers the 52 species known to the Willamette Valley of Oregon (Portland to Eugene): 35 dragonflies and 17 damselflies. It includes identification tips and a short natural history for each species, including flight times. The photos are large and clear though often are posed using chilled specimens. This is currently the best reference for the Willamette Valley or Puget Trough.
Dragonflies and Damselflies of the West. Paulson, D. (2009, Princeton University Press).
This is the current “bible” on Western dragonflies. Dennis Paulson has covered all the Western species with an extensive
narrative and good pictures. He covers a basic description, identification issues, natural history, habitat,
flight season, and distribution. This is the first guide to the region that includes a range map for each species.
At 535 pages, though, it is not something you can carry in the field in your pocket.
I recommend making a little index for fast reference to the pages for your local species.
There are several web sites that include photos of our regional dragonflies.
Credits: Photos were selected from the dirttime.ws website, copyright by Dennis Deck.