You need two sturdy cardboard tubes about 5 inches long, clear packaging tape, cord or ribbon, markers, stickers and whatever else you want to decorate them with. The tubes I used are very thick and sturdy. Thinner tubes from toilet paper rolls could be used but will not last as long in the hands of a toddler. You may want to tape them together using colored or patterned duct tape for extra strength.
First, I gave Lucy markers and let her go crazy on the tubes.
She went a little too crazy with the markers (thank goodness they were washable)! Next, I let her decorate them with whatever stickers we had around.
After Lucy was satisfied with her decorating job I taped the two tubes together with lots of clear packaging tape. Tape them until they are very tight and completely covered (keeps little fingers from peeling off the stickers and putting them all over the house!).
For the neck strap I raided my ribbon stash and found a green, cotton cord about a yard long that ended up being the perfect length for Lucy to get over her head. I looped the cord through each side and tied it tightly and then taped over it to hold it in place.
Now my little explorer can go bird watching, on safari, or just pretend to spy on her baby sister!