There are several opportunities for students who want to volunteer at animal organizations.
Some organizations will require attending an orientation session before receiving an application. All of them will require training sessions before volunteering and working directly with the animals. Depending on the organization spots could be available at different times or in the summer.
Here are some of the options students have:
Portland Audubon: https://audubonportland.org/get-involved/volunteer/
Oregon Zoo: https://www.oregonzoo.org/get-involved/volunteer-zoo
Multnomah County animal shelter: https://multcopets.org/volunteer
Oregon Humane Society: https://www.oregonhumane.org/get-involved/volunteer/