Build a nesting block for bees.

Honey bees are crucial to producing about one-third of all the food we eat. The list of crops that simply won’t grow without honey bees is a long one: Apples, cucumbers, broccoli, onions, pumpkins, carrots, avocados, almonds … and it goes on. (Download NRDC Bee Facts for full list). Without bees to pollinate many of our favorite fruits and vegetables, the United States could lose $15 billion worth of crops. Hypothetically speaking, right? Hmmm…no. Researchers estimate a third of all honey bee colonies in the U.S. have disappeared.

One of the biggest challenges bees face is finding suitable nesting sites. The majority of our approximately 4,000 species of native bees (honeybees are a European import) are solitary — essentially, single mothers raising their young alone. Having no hive to defend, they’re not aggressive and rarely sting.

About 70 percent of native bees are ground nesters. A small patch of bare earth in a sunny spot — as little as 1 square foot — is all they need. The remainder are mostly wood nesters: They’ll occupy holes in trees bored by beetles, or they’ll move into nesting blocks like the one shown here. The female bees will lay their eggs in the holes, then seal them; their offspring will emerge next spring to carry on.

Many bees make themselves at home in holes drilled in wood blocks. Make it a project with your kids to make a nesting block for bees to put in your garden or yard. It’s easy. The Xerces Society offers these simple instructions:

1. Start with a piece of wood at least 4 inches deep and 8 inches long. Use untreated lumber and avoid cedar, which is toxic to insects.
2. Drill a grid of holes varying from 3/32 to 3/8 inch in diameter, spacing them approximately ¾ inch from each other. Drill deep holes, even going all the way through the block, to maximize the nesting depth.
3. Attach the block to a backing board and install a sloping roof that extends in front of the block to shelter the holes from the elements. Mount the backing board on a sturdy fence, post, tree, or building in a site where the holes will get only gentle morning sun.
4. Or as an alternative prepare nesting tubes: Any hollow plant stems can be cut into 10-20 cm long sections. Bamboo canes have sealed nodes, cut them so that long hollow sections are exposed; they come in a variety of internal diameters, those up to 1 cm will be used by some species of bee. When cutting down plant stems, keep some sections of hollow stems of shrubs and/or fairly tough herbs (even down to 2mm diameter hollows). Cut bramble and rose stems have pith into which tiny bees make their own burrows. If a source of reed is available, then dead hollow stems can be broken into sections.
5. Bundle the tubes with garden twine, string or wire.
6. Hang them up - place and anchor your nest on a sunny or partly sunny shelf on a shed, or similar improvised situation. Ensure that the nest is protected from the rain.