In the effort to combat garden insect pests, there is a cadre of carnivores ready to rush to the chore. Many birds are omnivores, eating both seeds (unfortunately some of those that gardeners just lovingly put to bed in their gardens) and insects in all their forms. Cabbage worms are small and hard to spot, but for sparrows and other perching birds, they are prime targets. Mosquitos and other tiny flying insects are nearly invisible to humans, but to bats they are food on the wing.
How to enlist these partners to keep the garden in balance? It takes a little observation and maybe a little design. Birds flit and fly through the landscape all the time. They may be in search of their next mate, their next meal, or food for their chicks. Food is usually tops on the list. Giving them the roost they need as they roam the urban forest can make all the difference in their participation in an eco-friendly garden. A secure vantage point to spy out bugs can be as simple as a three-foot-long stake stuck in the ground near those cabbages, or the whips pruned out of the plum tree plunged into the soil beside the aphid-prone artichoke. From these perches, birds can pick out their next meal while also keeping an eye on the sky for any dangerous predators, safe even from the household feline.
Other attractions that may encourage birds to visit include a water source and material for nesting. Security will again be an issue. Bird baths, whether of the classical basin on pedestal type or a simple saucer of water, should be placed in the open where visiting birds can keep a lookout for danger. Wash and refill them often to keep bacteria and algae from fouling them. Nesting material choices vary greatly by species of bird, so a variety of materials can be offered. Palm fibers are a favorite of the hooded oriole, but crows like twigs. Phoebes and swallows need a water source, preferably with its own muddy edge to gather the cement for their nests. Human and pet hairs, even the “hairs” on some cactuses, find their way into the woven wonders of house finches and others. Keeping the garden too tidy will deprive avian residents of necessary resources.
Bats are rarely seen. They emerge from their roosts just at dusk and swoop soundlessly (to humans anyway) through the twilight. With their echolocation skills, they home in on insects that are also on the wing at that time of the night. One of the peskiest insects, the mosquito, is definitely on their menu. Other, larger insects also play a crucial role in bat nutrition, so it is not uncommon to find them feeding near street lamps and porch lights. Moths, flies, midges, and beetles may even be more filling than the tiny mosquito. Providing habitat for bats will not go unrewarded. The little brown bats that are native hereabouts roost in tree hollows or little-used buildings. They may even roost under the peeling bark of trees such as eucalyptus or in hanging clumps of Spanish moss.
For both birds and bats, there are also plans for manmade structures that they may find to their liking. Everyone has heard of birdhouses, but how about adding a bat house to the garden, too?
• Plant tropical and subtropical varieties such as avocado, bougainvillea, and palms now that the soil is warming up.
• Plant warm-season vegetables and summer annuals such as amaranth, petunia, sunflower, and zinnia.
• Watch for sucking insects, and blast them with the hose, but leave a few so that beneficial insects will have a reason to come to your aid. Control ants that may be “herding” them.
• As cymbidiums finish blooming, feed with high-nitrogen fertilizer.
Virginia Hayes, curator of Ganna Walska Lotusland, will answer your gardening questions. Address them to Gardens, The Independent, 122 W. Figueroa St., S.B., CA 93101. Send email to email@example.com.