I love walking on beaches because each day and each beach is so different.

Last week as I was picking up pieces of plastic from Kailua Beach, a woman asked me if I'd like to put my trash in her bucket instead of my pockets. “;Thanks,”; I said, “;but I'm collecting these chips for a project. I'm making a mosaic with them.”;

She looked at the junk in her bucket. “;And here I've been throwing this stuff away every day. Would you like me to save it for you?”;

“;I'd love it,”; I said.

So now, before I start my morning walk, I check a bag hanging on a tree to see what the woman collected for me. The contributions from this friendly stranger make creating the art more fun than ever.

I didn't always need help collecting flotsam, but over the last few years, the message about plastic pollution in the marine environment seems to have reached a lot of people. The sight of beach-walkers picking up trash as they go is now common in some areas, and those beaches are noticeably cleaner.

One woman I met last week, though, was piling small pieces of wood high on the beach. “;Are you going to build fires here?”; I asked, hoping this wasn't the case. Beach fires make our white sand black with soot for months afterward.

“;No,”; she said. “;I'm hoping someone will haul it away. Wood isn't natural on Hawaii beaches.”;

“;It isn't?”; I said.

She explained that most wood lying on our beaches comes from species alien to Hawaii, and therefore it's unnatural.

“;These sticks don't seem to be a problem, though,”; I said.

“;You won't think that when you break your leg on one,”; she said. “;This stuff is dangerous.”;

My little dog, Lucy, and I promptly moved on.

Some people believe dogs are not allowed on Oahu's beaches, but that's not entirely true. It's OK to walk your leashed dog on some beaches here but not all. To see which beaches ban dogs, go to the Hawaiian Humane Society's Web site at http://www.hawaiianhumane.org and click on Dog Parks and Beaches.

One complaint about dogs on beaches is inadequate poop pickup. When Lucy and I walk dog-friendly Kailua and Lanikai beaches, I carry plastic bags attached to her leash to clean up after her. The good news is that everyone I see with dogs does the same.

Well, almost everyone. Recently after someone left their dog's stinky pile on the sand in Lanikai, I saw another dog walker hurry over to bag it up. “;We can't let a few people spoil it for the rest of us,”; she said cheerfully when I thanked her for doing that. “;We dog lovers have to work together on this.”;

And they do. At several beach access points, I've seen homemade containers of plastic bags with reminders to please clean up after your dog. Such dog poop awareness is a change from the past, proving that Homo sapiens can be trained.

After being away for two months, I noticed Kailua Beach has received a gift delivered by waves rather than trucks: more sand. The embedded concrete blocks near the boat ramp are less exposed now than when I left. When I wrote about the erosion there last December, several readers e-mailed predicting the ocean would bring the sand back in its own good time. For now they're right.

When I set out for my beach walks, I don't know who I'll meet or what will happen, but I do know this for sure: I will never be bored.

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