How to Identify Spiders in Oregon

Look for a web that corresponds with the spider to narrow down whether it is a web building spider or not. There are four main types of spiders in Oregon, two of which spin webs and two do not. Jumping and crab spiders are wandering spiders, while funnel-web and cobweb weavers build webs.

Make observations about the spider web. Funnel-web weavers create webs that act as a long funnel, and hide in the bottom awaiting prey. Orb weaving spiders create classic round-shaped webs. Cobweb spiders weave webs that are much more fragile and disorganized. Messy, silky spider webs are indicative of a black widow's nest, so avoid them.

Note distinct details in the appearance of the spider. Jumping spiders have two prominent eyes, two smaller, and then four smaller eyes. Many jumping spiders in Oregon are shiny-metallic, red and black, earth-toned or green. The black widow spider is known for its red hourglass-shaped marking, and Oregon's orb weavers have large abdomens and distinct markings that differentiate each species. Crab spiders keep their front-most two pairs of their legs outward to the side, resembling a crab.

Judge the spider's movement for additional identification clues. Jumping spiders move quickly in short bursts and are known for pouncing on prey unexpectedly. When you irritate an orb weaver, the likely reaction is bouncing, which causes the web to vibrate. The black widow is likely to hang upside-down, exposing the abdomen while waiting for prey.

Pay attention to the size of the spider. Large funnel-web weaving spiders such as the barn funnel weaver, giant house spider and hobo spider can differ enough in size from other spiders that you can identify them with a field guide. Compare different possibilities using a field guide by comparing the relative size of each spider that you encounter.