Photo Story: Beaver Monitoring 2018

Four volunteers met at our Cedar Mill preserve in Beaverton to walk the wetland in search of beaver dams. Megan Garvey explain the process, route and how to record data.

As water in our wetlands starts to recede from summer heat, beavers start to get busy, building dams. It is also the time of year when juvenile beavers leave their parents lodges and strike out on their own, making it the perfect time to look for beaver activity in our urban preserves.

25 volunteers have been trained to help with The Wetlands Conservancy and Clean Water Services community science beaver monitoring program.  July through September volunteers will be looking for signs of beaver, beaver dams and lodges in the Hedges, Nyberg and North Johnson Cedar Mill Creek subbasins. Recording and mapping beaver presence and use will help us  develop  best management practices to maximize the benefits created by beaver activity and mitigate some of the conflicts with human uses and infrastructure.

We walked in the upstream direction, looking for signs of beaver. For this type of monitoring it is important to walk upstream in case we cause any disturbance it would be behind the group.

This group of volunteers helped with our amphibian monitoring of this site in the early spring. Notes were made on water levels and clarity of the water.  Then we saw a PACIFIC LAMPREY!!! This species needs clean water and healthy marsh sediment to survive it’s long juvenile phase ( 3-7 years). Like salmon, these young lampreys will soon make the long journey to the ocean, only to return when they’re ready to breed and pass on.

We found our first beaver lodge and it showed all the signs for active and healthy beavers.

Beaver tracks! Beavers in urban settings are almost exclusively nocturnal so we look for fresh signs, rather than expecting to see them. These tracks, in the muddy banks of the wetland, are sure signs that beavers have been active very recently.

As we moved up the creek we found a series of small beaver dams above the big beaver lodge.


Megan,  never afraid to get her waders wet!

Wapato, a native Pacific Northwest wetland plant was in bloom! A sign of a healthy wetland.


Lot’s of pollinators were out, caught this Yellow Face Bumble Bee (Bombus Vosnesenski), a west coast native, out searching for pollen on a blooming Spirea shrub.

Successful first beaver monitoring! Boots off, suns out, thank you to our wonderful volunteers!

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