House Sparrow banner image copyright 2023 by Jerry L. Mennenga, used with permission.

My morning walks in fall 2016, when I was a visiting scholar at Magdalen College, Oxford, I saw House Sparrows only occasionally, and it was not in the wilder areas of Christ Church meadow. It was along the back edge of the meadow where some apartments had bird feeders

[Denis] Summers-Smith attributes the general decline since 1990 to changes in agricultural practices. Crops are increasingly planted in the fall, not the spring. Instead of letting grasses mature to hay in the field, they are cut for silage before setting seed.

Increased use of herbicides and pesticides may also contribute to House Sparrow decline. Other issues include predation by cats and lack of sufficient insects to feed the young.

I always think that when an organism that is tightly associated with us declines, we had better start considering what we are doing to our environment. After all, even in North America House Sparrow numbers declined by 84 percent between 1966 and 2015, according to the North American Breeding Bird Survey. But they are not going extinct.

 Strassmann, Joan E. Slow Birding, The Art and Science of Enjoying the Birds in Your Own Backyard. New York:  TarcherPerigee, 2022. Pages 150 – 151.

In June of 1962 The New Yorker serialized Rachel Carson’s book Silent Spring. This was the first exposure, for many Americans, to the unintended effects of DDT and the byproducts of this pesticide. The Environmental Protection Agency (EPA) banned DDT (dichloro-diphenyl-trichloroethane) in the United States in June 1972. DDT remains available in other parts of the world even though many classes of insects have developed a resistance to the chemical. (Neonic), (Wiki)

The removal of DDT and related compounds prompted the chemical industry to develop new pesticides, a broad term which includes herbicides to control unwanted vegetation; insecticides to kill or control insects; and fungicides. Over 800 pesticides are registered for use in the United States. (Neonic), (Primer), (NIEHS)

New generations of pesticides, organophosphates and the more recent neonicotinoids insecticides, appeared to be safer to vertebrates and effective at controlling invertebrate pests. These are systemic insecticides applied to seed coatings and absorbed into the entire plant. These seed coatings, however, are, “not considered ‘pesticides’ so their use is neither tracked nor directly regulated by the EPA.” (Neonic)

Recent studies have demonstrated that exposure to neonicotinoids caused migrant birds to lose weight, lose their sense of direction, and delay their migration. Birds may be harmed by direct contact with these and other pesticides, or by eating contaminated seeds or prey. Pesticides also reduce the number of insects that bird need to survive and raise their young, an important source of protein for growing chicks. (Migration)

In humans, studies sponsored by the National Institute of Environmental Health Sciences (NIEHS), the National Cancer Institute (NCI), the EPA, and the National Institute for Occupational Safety and Health (OSHA) “have linked pesticides to risk for Parkinson’s disease, thyroid disease, diabetes, kidney diseases, rheumatoid arthritis, and shingles (herpes zoster), among other health issues. Evidence suggests that children are particularly susceptible to adverse effects from exposure to pesticides, including neurodevelopmental effects.” (NIEHS), (Tier)

Pesticide use should be avoided as much as possible to allow all the life in your garden to flourish. Insects are in important element of many birds’ diets and are particularly critical for baby birds: 96% of land birds feed insects to their chicks. As you get to know the insect life in your garden, you may be amazed at the varied assortment of fascinating creatures you find there. (FAQ)

A diversity of native plants will also attract wildlife that will keep your plant-eating bugs in check: Not only birds but also frogs, toads, bats, and insect predators such as dragonflies, praying mantises and lady bugs will help keep your garden in a healthy balance. (FAQ)

If bugs are persistently devouring a favorite plant, however, some low-impact alternatives are available. Choose organic products that break down quickly in the environment such as insecticidal soap, neem oil, or pyrethrum, and apply sparingly and according to instructions. (FAQ)

NOTE:  Neem oil is an insect growth inhibitor and non-toxic to birds. Because neem oil prevents insects from developing further, it can prevent bee larvae from developing if adult bees feed neem oil-coated pollen to their larvae. Please avoid using neem oil on flowers or remove open flowers from plants being treated with neem oil.  (FAQ)

An alternate management that is safer for wildlife is to promote the use of birds of prey to eliminate rodents from the environment, thereby also eliminating toxic rodenticides. Anticoagulant and other rat poison products designed to kill rodents are also killing birds of prey, pet dogs and cats, and many species of wildlife, including several endangered species. These products are also poisoning children, even when the products are used in accordance with the directions on the packages. (RATS)

Similar results have been documented with a variety of birds with a variety of pests. Studies ranging from orchards in Michigan to vineyards in California and New Zealand show that birds including American Kestrels, Barn Owls, and Western Bluebirds are better than chemicals at reducing pest damage. (Farm) In some cases providing natural habitats, a water source, and a nesting location can attract aerial insectivores (swallows, swifts, martins, nighthawks, and flycatchers) to control insect populations during the day or at night. (Nest)

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