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The Gardener’s Feathered Friends
My story of the “quail tractor” at the beginning of this chapter hints at the roles birds can play in the ecological garden. But, as with insects, many
gardeners don’t welcome birds into the garden or orchard with unambiguously open arms. Birds can decimate a berry crop, peck holes in fruit, and
scratch up small seedlings. Often these problems arise because good bird habitat is lacking, and the birds are reduced to making do with what’s
available (in other words, your plants). I’d argue that in a well-designed, balanced landscape, birds do far more good than harm. They are supreme insect
predators, attacking both leaf-munching caterpillars and flying bugs. Many birds eat seeds, reducing the number of weeds. In return for this food, they
leave small gifts of rich manure. Individual bird droppings may not amount to much, but when a gardener concentrates manure by hanging a feeder or by
some other tactic, plenty of fertilizer can accumulate. Birds also scratch the soil, simultaneously tilling the ground, removing insects and weed seeds, and
uprooting weed seedlings. Some small birds are good pollinators. And then there is the simple joy that birds bring, with their bright plumage, burbling
song, nest building and family raising, and their endlessly varied behavior as they hunt, court, stake out turf, and socialize. A yard without birds seems a
sterile place.
To see how to attract birds to the landscape and to benefit from them, let’s once again take the ecological view. What kind of habitat gives birds all that
they need? Once we’ve answered that, we can see how to blend bird habitat, and all the gifts birds offer, into the garden.
Imagine a backyard of bare ground. A little bare earth is useful for birds, which will take dust baths in dry soil to subdue mites and other parasites. Birds
also eat grit to aid digestion. But without shelter from predators and the elements, no bird can live here. Occasional visitors might come to pluck worms or
ground-dwelling insects from this empty place, but they will not stay for long.
Allow a low ground cover to carpet the soil, and the friendly microclimate and greenery will attract several types of insects. Now ground-nesting birds
such as meadowlarks and certain sparrows may appear to feed on bugs and seeds. These two types of food foster diversity in bird residents, because
insect-eating birds have long, slender beaks to pluck insects from foliage, while the bills of seed-eaters are short and thick to crack tough seeds. As the
environment grows more complex, bird anatomy and behavior diversify as well. In other words, more species of birds can coexist in complex habitats than
in simple ones.
Bring in a little more plant diversity: tall grasses. Thick, high grass offers birds protection from predators but also hampers bird flight. Birds that live in
tall grass are different from ground-nesters. They have short wings and tails to nimbly maneuver through the grass, hopping rather than flying.
This is still a fairly impoverished home. Let’s add some shrubs, which encourage diversity in several ways. One is by moving firmly into the third
dimension, height. This provides perches for birds, where they can sit and watch for prey rather than hopping about in continuous search. Sit-and-wait
hunting conserves energy, leaving more for breeding and social behavior. Perches also encourage flying, so the wings and tails of shrub-dwelling birds
are bigger than the sawed-off stubs of grass residents. Also, birds that hunt bugs on the wing have broader bills to raise the odds of nailing insects with
each swoop. Nests, now off the ground, are safer, cooler, and drier, so more nestlings survive.
Perching birds are superb seed dispersers and can bolster plant diversity on their own. Researchers found that when they provided perches in a field,
the number and variety of seeds brought by birds skyrocketed. If in our landscapes we offer birds a few shrubs for perching, they’ll introduce many new
plant varieties on their own. This in turn will attract new insects, which will bring more new birds, which will ferry in more seeds, and up and up the cycle
builds.
Another boost to diversity offered by shrubs is from woody tissue. Grass and herbs have soft stems and foliage; thus insects can munch them with
ease. But the woody stems of shrubs will resist a soft-mouthed bug. Woody stems offer a whole new niche, drawing insects with tough jaws or piercing
mouthparts. Thus, a shrub-filled landscape is home to yet more species of insects, and that means more types of birds to eat them.
Within the shrubby canopy, small birds are protected from predators. These birds can hop from twig to twig, snapping up insects. They need sharp,
pointed beaks to poke into small places in search of food. So here come some more new species.
The move to the third dimension hugely boosts diversity, opening up many new opportunities for food sources and consumers of that food. As the
habitat diversifies, more and more birds find niches, and this creates more variety in turn. Also, a combination of herbs and shrubs will nurture not only the
birds dependent on each but also new species that colonize the edge between the two habitats. Once again, the whole is more than the sum of the parts.
Now we can add some trees to the mix. The combination of tree trunk and canopy creates a new structure, where birds can glide in the open expanse
below the crowns. More flying birds will arrive, and bigger ones, too, since thick branches can support large birds. And once again, this creates new
insect niches. The tree trunks, with thick bark and broad surfaces, allow new species of bugs to feed, hide, and lay their eggs. The birds that eat these
bugs need specialized beaks to probe the bark and an anatomy modified to hang sideways on trunks instead of perching upright. So trees hike bird
diversity still further. Life among the trees is safer, too. Birds and nests in the canopy are protected from predators lurking on the ground, which must now
learn to climb for their food.
This shows how a diverse habitat, with many shapes, sizes, and varieties of plants, attracts birds (and insects) of many species and lifestyles. Birds
play a critical role in any ecological garden, for the reasons given at the beginning of this section. Although some people landscape their yards specifically
to attract birds, every yard can have some bird-friendly elements in it. Of course, we can design so that most of these elements will have more than one
function, benefiting the human and other occupants and contributing to the health of the entire miniecosystem. Let’s see specifically what needs to be
included in the ecological garden to bring birds into it, and how those pieces fit in.
An ideal, diverse habitat for birds will have four key elements. They are:
1. Food. Bird foods fall into three main categories: fruits and berries, insects, and seeds and nuts. Some birds are specialists, eating mostly from one
group, while others aren’t so fussy. Hummingbirds and a few others also drink nectar, but even hummingbirds get over half their nutrition from
insects. To feed a wide variety of birds, a garden needs insectary plants (many of which offer nectar, too), grasses and herbs that yield seeds, and
shrubs and trees with nuts, fruit, and berries. A wide variety of species to continuously provide food over a long season is best. Many fruits and
berries hang on into winter, and these species will invite birds all year. Table 7-2 is a brief list of plants that are all-around useful ones for birds and
have other functions as well. A more comprehensive list of plants that feed birds would fill many pages, so I will refer the reader to the bibliography
for some good books on the subject.
2. Water. The most natural source of water for birds is a pond or small stream with shallow edges. An alternative is a birdbath or other container less
than two inches deep. A shrub or other shelter very close by will give birds an escape route and allow them to check out the water from a safe perch.
Birds will also frolic in a sprinkler’s spray or other moving water.
3. Shelter and protection. Birds know that death from predators or bad weather is always near. Thus, food and water offer little enticement for birds
unless accompanied by shelter from the elements and protection from predators. Dense shrubs, tangles of vines, plants with thorns, and leafy tree
canopies all provide safe havens from predators. Thick evergreen foliage will shelter them from wintry winds, heavy snows, and extreme cold. For
nesting, birds need plants with foliage that will exclude rain, hot sun, and sharp-eyed predators. Birds often nest at specific heights, so a diverse
array of shrubs and trees will offer potential homesites to many species. Wide, dense plants are useful since lots of birds prefer to nest deep inside
a broad hedge or bush.
