Sunny Slope Orchard

Sunny Slope Orchard
In the coast range foothills overlooking the Sacramento Valley

Monday, April 18, 2011

Birds of Spring

Male Bullocks Oriole
This time of year the air is a symphony of bird sounds as mating season gets into full swing. Whether calling to a mate, announcing their territory, or just singing for the fun of it, birds are especially vocal right now and are a joy to watch and photograph.

We tend to put birds into categories based mainly upon their diet:
  • Birds of prey (hawks and owls) get a totally positive rating for their service eating varmints.
  • Insectivores and seed eaters (various flycatchers, doves, goldfinches, quail, robins and hummingbirds) get a positive rating for eating insects or seeds and mostly avoiding orchard fruit.
  • Voracious fruit eaters (blue Jays, orioles, house finches, starlings, sparrows) get either a mixed or negative rating due to bad manners, eating too much fruit, and generally being a pest. Of course not all birds are necessarily completely good or bad. Our Bullocks orioles are about the most dramatically colored birds around and always a treat to watch, but I'd like them better if they didn't eat our fruit.
A barn owl peeks out of his home
Owls are some of our favorites, especially barn owls. These beautiful creatures have our undying gratitude for solving our serious gopher problem some years ago. Barn owls nest only in cavities (hollow trees, old buildings, or man made nest boxes) so several years ago I installed several boxes on our property and around the area to entice more owls to settle here.
Seven young barn owls in their nest box

Now we enjoy the comforting sounds of barn owls at night year-round, knowing they are on the job keeping rodent pests in check. You can see more of our owl photos in this post.

Besides barn owls, great horned owls, screech owls, and burrowing owls inhabit the neighborhood. And a variety of hawks take over varmint hunting duties during the day.

A male bluebird sits outside a nest box
Western bluebirds and tree swallow populations are also increased by nest boxes. We have several boxes around the orchard that house nesting pairs every year. Both birds eat mainly insects, or small wild berries in winter.

A bluebird enjoys a drink from the birdbath

As we have encouraged beneficial birds with nest boxes, bird baths and a diversity of food sources, we've noticed an increase in their numbers compared to pest birds. But we still have plenty of fruit eaters that require elaborate bird scare contraptions during harvest season - more on that when the time comes. In the meantime we're just enjoying the sights and sounds of our feathered friends.

A goldfinch frolics in the bath

Acorn woodpecker

A dove sits patiently in her nest

Wednesday, April 6, 2011

Promoting Balance in the Orchard

It is now early April and we're nearing the end of a very wet rainy season. The cover crop on the orchard floor has flourished, growing tall and dense. Starting in early winter the thick growth of bell beans, vetch, field peas and mustard helped to capture rain runoff and prevented erosion.

Once in the bloom phase the cover crop has attracted and nourished many types of beneficial insects which help keep harmful pests in check.

Just about any flowering plant will attract insects and other creatures both good and bad. The key to natural pest control is to promote a diverse biological environment so natural predators can help keep harmful insects and animals in check. In the photo at left a bell bean plant is infested with black aphids. These aphids do not attack fruit trees, but they do attract lots of green lacewings and lady bugs, which are then present to control the green aphid that does infest fruit trees. And sure enough this plant is covered with dozens of lady bugs and their larvae (the larvae are the alligator like creatures).

Another benefit of a good cover crop is natural soil fertility. Besides mining the soil for deep minerals, the legumes in the mix have the wonderful ability to add nitrogen to the soil. So called nitrogen fixing bacteria in the soil colonize the roots, forming the white nodules shown at right. These bacteria live in a symbiotic relationship with the plant, capturing nitrogen from the air. When the plant dies, excess nitrogen is then available for other crops, in this case the fruit trees.

But as the rainy season ends it is time to conserve as much soil moisture as possible to see the trees through the dry months ahead. So I've just mowed down the cover crop to stop it from drinking up any more of winter's rainfall. I use a flail mower which chops the growth into a uniform layer of mulch. This residue will soon dry to a straw color, reflecting sunlight and keeping the tree roots cool while reducing evaporation from the soil surface. The decaying roots and mulch will now be digested back into the soil in nature's continual process of cycling nutrients from plant to soil to plant again.