What's Happening to Birds?
Last updated 4/28/2023 at 11:05am
Recognizing the Work of Borrego Springs Dark Sky Community, during International Dark Skies Week, April 15 – 22, this article in the continuing series on species extinction, focuses on light pollution and birds.
Light pollution is literally killing birds. This sad and important information comes thanks to the Borrego Dark Sky Community, created to protect Borrego’s night sky, and educate the community on the detrimental effects of light pollution on humans, mammals, and other species, like birds.
According to the National Audubon Society, there are some 11,000 known avian species worldwide. They’re present from pole to pole, from high mountains and deserts to remote islands and cities. They play integral roles in every biome, pollinating plants and spreading seeds, including fruit- and berry-bearing varieties that feed many animals. Each year, they consume 400 million to 500 million metric tons of insects that can damage crops and kill trees. A single bird can eat enough bugs to save 29 kilograms (65 pounds) of coffee on a Latin American plantation.
And people love birds: In the U.S. alone, the bird-watching industry is valued at $41 billion per year.
Birds are also important indicators of the state of the planet – and they’re in trouble. Since Carson’s time, numbers have dropped by “many billions,” says Allinson, a senior global science officer at BirdLife International. Nearly half of all species (5,245) are declining. Anyone alive in 1970 in the U.S. or Canada has seen one in four birds disappear during their lifetime, 2.9 billion in all: from robins and sparrows, to blackbirds, finches and other familiar backyard denizens.
Birds are getting hit from all sides: In the Anthropocene, humans are altering the natural world to an “unparalleled degree,” disrupting and devastating ecosystems and driving extinctions. It’s impossible to gauge how many species have vanished globally since the passing of the dodo in 1681 – the first recognized bird extinction.
The best guess comes from the Red List of Threatened Species. This database, maintained by the International Union for Conservation of Nature, tracks wildlife population trends. The list has recorded 159 bird extinctions dating back to 1500 C.E., when the European Age of Discovery began impacting the world. An additional five species only exist in captivity; 22 more are “possibly extinct.” Most of those are flightless or island species.
Artificial Lights have Devastating Effects on Many Bird Species
Light pollution is a factor in the demise of birds. The effect of artificial lights on birds has been known for centuries. In the past, people used flame and lights to attract birds at night to capture them for food. Since their inception, there have been reports of seabirds attracted to the light beam of lighthouses.
Artificial lights can “trap” migratory birds by bleaching their visual pigments, causing them to lose sight of the horizon and circle within the cone of light endlessly. They then can die from exhaustion or collision with the light source. It can extend the day for diurnal species of songbirds, making them more susceptible to predators as they sing out their location, or causing them to breed too early since they associate breeding with longer days.
Artificial light changes day/night patterns, resulting in not getting enough sleep, not having enough downtime for the body to repair itself, alters reproductive cycles”
Artificial lighting also attracts some organisms (moths, frogs, sea turtles), resulting in them not being where they should be, concentrating them as a food source to be preyed upon, or just resulting in a trap which exhausts and kills them. It repels some organisms, excluding them from habitats where they might otherwise make a living.
For birds that migrate or hunt at night and navigate by moonlight and starlight, artificial light can cause them to wander off course and toward the dangerous nighttime landscapes of cities. Every year millions of birds die colliding with needlessly illuminated buildings and towers. Migratory birds depend on cues from properly timed seasonal schedules. Artificial lights can cause them to migrate too early or too late and miss ideal climate conditions for nesting, foraging and other behaviors.
Many insects are drawn to light, but artificial lights can create a fatal attraction. Declining insect populations negatively impact all species that rely on insects for food or pollination. Some predators exploit this attraction to their advantage, affecting food webs in unanticipated ways.
Ecosystems: Everything is Connected
Another human-caused danger to birds and other species living in Borrego is disturbing and destroying their nests and habitats. This became an issue to Borregans, when the community learned that County’s Defensible Space Ordinance required the removal of the dead palm fronds that form skirts around palm trees.
As reported previously in the Borrego Sun, birds, like the Hooded Oriole, the American Kestrel, Great Horned Owl, and Barn Owl (eats four rats per night) inhabit palm skirts.
The list of birds found in Borrego that use the palms as nesting and roosting, are Eagles, Cassin’s Kingbirds, Starlings, Quail, and the iconic Roadrunners.
In addition to birds and raptors, many species of insects such as bees, along with bats, build nests in palm trees.
Protecting both, due to the fact that 80% of human food sources are dependent on pollination by bats and bees, should be required. Protected species habituating in palms include the Snowy Owl, Egrets and Herons. Why worry about bees and bats? They populate the desert, live in caves, under roofs, and in the skirts of palm trees. They aren’t attractive, and an ungrateful bat bite or bee sting can be painful. Yet 80% of the fruits and vegetables humans eat depend on these tiny pollinating machines. All nature is not beautiful or enjoyable to be sure.
Other critters that nest, seek cover and food sources from palm trees are skunks, and raccoons. When a palm is dead it’s especially attractive to cavity-nesting birds. Woodpeckers easily excavate holes in areas of decay or in spaces where previously removed fronds create suitable space. Where entire decayed sections exist, other cavity nesting birds such as Barn Owls, the American Kestrel, and non-native parrots and House Sparrows find many holes in which to nest.
Rachel Carson warned in the first book ever written about a crisis for wild species, when she wrote Silent Spring, in 1962.
Recognized as the first environmental call to action, the subject was the large losses of bird life, and danger to human health, resulting from the use of deadly chemical substances in agriculture. She was humiliated and destroyed by the scientific community and corporate chemical interests.
Yet today, her words still ring true. “What if one morning, the world awoke to silence without the thrill of one bird?” she asked. Silent Spring challenges the thinking that nature is to serve people and is to be controlled, and implies our moral responsibility to nature, that “We must not cause unnecessary loss of non-human or natural life and reminds us we share the same environment.”
The Borrego Dark Sky Community and existing coalitions work to protect the night sky from the effects of light pollution with regulation, requirements and tips to keep the Borrego sky dark at night. Thus, allowing residents and visitors to Borrego Springs to view a sight not seen in urban environments: The Milky Way in all its glory.