Geocaching basics

Afton State Park, 1-2 p.m. Saturday

• Learn how to use a GPS unit to geocache and locate hidden treasures in state parks. The program is geared toward beginners. Bring your own GPS unit. A few are available at the park. (651-231-6968; mndnr.gov/afton)

Maple syrup demo

Fort Ridgely State Park, 10-11 a.m. Saturday

• Meet at the upper picnic shelter. Learn how to tap a tree, collect sap and boil it to produce maple syrup. (1-507-384-8890; mndnr.gov/fortridgely)

• Lake Bemidji State Park, 1-3:30 p.m. Saturday: Watch a demonstration of a tree-tapping. Collecting sap and processing it will take place from 1-3:30 p.m. April 6-7 and April 13-14. (1-218-308-2300; mndnr.gov/lakebemidji)

• Baker Near-Wilderness Settlement, 3-5 p.m. Sunday: Learn to identify a maple tree and help tap a tree. Learn how an evaporator boils sap into syrup and taste-test real maple syrup. Cost is $6. Call 763-559-6700 to make a reservation. Children under 2 are free. This program is open to all ages. (threeriversparks.org)

Bluebird volunteer orientation

William O'Brien State Park, 10 a.m.-2 p.m. Saturday

• Become a bluebird volunteer and help the birds raise their young. Nest monitors meet from 10 a.m.-noon; station volunteers from 12:45-1:45 p.m. Volunteers should plan to attend both sessions. (651-433-0500; mndnr.gov/obrien)

Outdoors CSI

Lowry Nature Center, 10 a.m.-11:30 a.m. Saturday

• Use clues to identify animals by their skulls. Call 763-694-7650 to register. (threeriversparks.org)