Returning Birds

For lo, the winter is past, the rain is over and gone

The flowers appear on the earth; the time of the

singing of birds is come, and the voice of the

turtles is heard in our land.

Song of Solomon 2:11-12

 

2ND WEEK IN MARCH

Returning Birds

 

In 1948, Paul Müller of Switzerland received the Nobel Prize for his work with DDT, considered the ideal chemical to destroy unwanted insect species (the fact that it also killed beneficial insects didn’t seem to bother anyone).  Then in 1962, Rachel Carson wrote Silent Spring, indicting DDT.  Not only did it kill insects, it had entered the avian food chain and was disrupting the reproductive processes.  Many species of birds had already been destroyed and many more were at risk—we were indeed threatened with a “silent spring”, a spring in which no birds sang, because there were no birds (Daniel Quinn, The Story of B, 1996).  But because of Silent Spring, DDT was banned; and some birds, such as the robin, have made a comeback; many more are still struggling to recover from their almost complete devastation.

DDT and other pesticides indiscriminately not only kill harmful pests, but beneficial insects, birds, and other benign creatures, as well.  Throwing chemicals at pests doesn’t eliminate all of them; there will always be a few that are immune to pesticides.  Then they will make a comeback, passing on their genes for pesticide resistance.  Meanwhile the predators of the harmful pests have also been killed and their comeback is not as quick or bounteous as that upon which they’ve been feeding.  So now we have pesticide resistant pests and have also eliminated their natural predators.

In 1948, just before the advent of DDT, American farmers used 15 million pounds of insecticide and lost 7% of their crop; today they use 125 million pounds and lose 13 percent (Evan Eisenberg, The Ecology of Eden, 1998).

The bluebird carries the sky on its back.

Henry David Thoreau

 Eastern Bluebird

Bluebirds were common when I was a child; but are scarce now.  Bluebird populations were devastated with the advent of DDT—their population plummeted 90%!    Also contributing to their decline was the loss of natural nesting places such as dead trees, old orchards, and fence posts.

The bluebird, however,  is making a strong comeback—its population increased 400 percent between 1975 and 1991, states Joel Greenberg in A Natural History of the Chicago Region, 2002.  This is due primarily to the placement of bluebird nest boxes throughout its range to take the place of the missing hollow trees and fenceposts.  Bluebird trails have been established throughout northeastern Illinois.  In just five counties over 700 bluebird houses have been placed in the proper environment at appropriate distances and then carefully monitored by an informal group of about 100 people, again according to Joel Greenberg.  This is a worthwhile and educational neighborhood project for conservation subdivisions.  Bluebird boxes have also been installed at country clubs, golf courses, and corporate campuses.

Isaac Walton Leagues and other organizations conduct workshops to instruct the public on how to build nesting boxes for bluebirds; they also provide instructions for placing them.

The boxes have to be mounted to metal posts or poles to keep field mice out (the mice will saturate the bottom of the box with urine) and placed in open, savanna-like areas (scattered trees growing in grassy and low groundcover)  with the entrance hole facing north, northeast, or east.  Placing the boxes only 5’ above the ground discourages other birds from nesting in them.  Avoid brushy areas, closed canopy woodlands, swampy areas, city lots, areas with large numbers of house sparrows, and any areas receiving pesticide applications.

Bluebirds like a shallow birdbath and are attracted to fruiting trees and shrubs.  They especially enjoy the fruit of Elderberry ( Sambucus canadendis)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gray Dogwood (Cornus racemosa)

 

 

 

 

 

Various brambles–this is Purple-flowered Raspberry (Rubus odoratus)

 

 

Native viburnum, such as Blackhaw (Viburnum prunifolium).

 

 

Other berried trees and shrubs that are favored are Serviceberry, Hackberry, Red Osier Dogwood, Black Cherry, and Choke Cherry, but 90% of the summer diet of the Eastern Bluebird is insects.  They will devour prodigious amounts of beetles and their larvae, grasshoppers, crickets, caterpillars, ants, spiders, and wasps (Verne Davison, Attracting Birds: from the Atlantic to the Prairie, 1967).

I gave my daughter a bluebird house one spring; the day I gave it to her she saw a pair of bluebirds house-hunting, trying to get into her wren house.  Excited, she had her husband install the bluebird house and another one on poles in the back yard that very evening.

 

Their back yard that overlooks a large open field is an ideal site to attract bluebirds.  Scarlet Oaks and Shagbark Hickory, along with various brambles, grow along the north edge of the field, while Sandy Creek flows through the far side. (The wire keeps house sparrows out, but doesn’t affect the bluebirds.)

The bluebirds took up residence at once, building a nest and raising a brood of five babies.  When the babies fledged, mom and dad immediately built a new nest in the other house and raised five more babies.  A marvelous success story—10 new bluebirds added to the native fauna in one summer

The worst threat of all to our favored birds is the loss of habitat.  Fragmentation has destroyed the vast stretches of woodland, forest, and prairie needed by many species, but favors instead those that prefer to live on woodland edges, such as crows, blue jays, and cowbirds. Cowbirds lay their eggs in the nests of other species, dumping out most of the previously laid eggs of the nesting bird.  The cowbird eggs hatch before the legitimate mother’s eggs do; and the larger, more demanding baby cowbirds get most or all of the food, causing the natural mother’s young to starve to death.

 

When a suburban area is young, it is often fairly rich in flora and fauna: richer, for instance than farmland where large-field monocropping is practiced.  In a young suburb the species of former ecosystems are joined by exotics, among them birds, ornamental plants, vegetables, and weeds.  They are joined, too, by a host of native opportunists.  They are lured by garbage cans, bird feeders, gardens, and other welfare programs; by eaves, chimneys, storm sewers, and other housing programs; or simply by the edge habitat of which suburbia is chock-full.  In North America, raccoons, skunks, white-tailed deer, cottontail rabbits, gray and red squirrels, chipmunks, red fox, cowbirds, crows and blue jays are some of the big winners in the animal kingdom.

Evan Eisenberg

The Ecology of Eden, 1998

 

 

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3 Responses to Returning Birds

  1. Denise Gehring March 10, 2012 at 5:23 pm #

    The bluebird box has a sting mounted on it. Is it to discourage raccoons? We use hardware cloth as a predator guard. Please fill me in. Thank you.
    Denise

    • PatHill March 11, 2012 at 9:22 am #

      As I mentioned, under the 2nd photo, the plastic-covered wire is used to discourage house sparrows from nesting in the box. The wire frightens the house sparrows, but not the bluebirds.

  2. Pat Sullivan-Schroyer March 12, 2012 at 1:05 pm #

    Great article, perfect timing! My husband and I were just discussing the issue of which direction the house should face. Thank you for the info!

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