Bird population declining

A flock of rosy finches feeding on the ground. Rosy finches

come to lower elevations during the winter. They often fly in flocks of 75 to 100 in a synchronous, swirling, swooping motion all together, called a murmuration of birds. (Photo by Flip Boettcher/The Flume)

Has anyone noticed that they have fewer birds at their bird feeding areas? It may not be your imagination.

More that 50 years ago, Rachel Carson warned about the loss of birds because of wide spread pesticide use in her book “Silent Spring.”

Now, according to a new report published in October in Science magazine entitled “Decline of the North American Avifauna,” bird populations have continued to decline in the last 50 years, dropping by 3 billion across America.

That is a 29 per cent decline from 1970 and equals about one quarter of the entire bird population. This is the first report of its kind to try to estimate bird population and losses in the Western Hemisphere.

Birds are conspicuous, easy to identify and count. Reliable records of them have been gathered over decades. Drawing on such data for North America, Kenneth Rosenberg, lead author and senior scientist at Cornell Lab of Ornithology, and a host of other researchers published their report.

The researchers also used data from weather radar stations to estimate changes in the total biomass of migratory birds each year between 2007 and 2017. This data showed similar bird declines.

According to the report, this represents a “loss of billions of breeding individuals across a wide range of species and habitats,” including those considered common and widespread, not just rare and endangered species, stated the report. “This loss of bird abundance signals an urgent need to address threats to avert future avifauna collapse and associated loss of ecosystem integrity, function, and services.” The Wall Street Journal called the report a “grim indicator of environmental health.”

This decline in the bird population could significantly affect the continent’s food webs and ecosystems, stated Rosenberg. The role of birds in our ecosystem is pest and insect control, pollination and seed dispersal. Uses of insecticides and pesticides, habitat loss, and climate change have all contributed to the bird decline.

There are 650 species of native and introduced birds that nest regularly north of Mexico. Grassland birds seem to be worst hit. These include sparrows, warblers, blackbirds, finches and meadowlarks, all “perching birds.”

Perching birds are medium to small birds well adapted for perching, and most are very fine singers. Most of them eat insects, though some eat fruits and seeds. Many of them are highly migratory.

Seven hundred million birds across 31 species of grassland birds that make their homes in fields and farmlands have vanished since 1970, according to the report. According to National Geographic, that’s a 53 per cent drop in the last 48 years.

Shore birds, whose nesting habitats are very susceptible to development and climate change, have declined by one third.

Neonicotinoids, one of the most widely used agricultural pesticides, may be partly responsible for songbird population declines. Wide use of pesticides kills the insects birds feed on and may also delay migration for lack of food to fly. Fewer insects mean, fewer birds.

National Geographic says bird loss is due to habitat loss, pesticides and a huge drop in insect populations. According to an article in British newspaper The Telegraph entitled “The Windscreen phenomenon’ by Sarah Knapton, in August 2017, wildlife experts have been warning of a decline of insects for decades.

The fall in the number of bugs in Britain has become so great that motorists have noticed that their windshields are now mostly clear of squashed insects. It used to be that a trip in summer would require the windshield to be cleaned periodically; now the glass is mostly clear.

This has been noticed across Europe and it is called the Windscreen Phenomenon. Human expansion and agricultural use also remove huge amounts of bird habitat.

The five bird families seeing the largest decline are New World sparrows, Old World sparrows, New World warblers, New World blackbirds, and larks. Surprisingly, waterfowl and raptor populations have made some recovery in the last 50 years.

Some things you can do to help the birds is to keep cats indoors. Feral and domestic cats kill an estimated 1.3 to 3.7 billion birds each year.

You can plant native plants to attract insects and the birds. Feed the birds. Avoid window collisions by hanging items in the window to break up the reflected landscape the bird sees from outside. Safely discard plastic bags by tying  knots in them and cutting all loops in your plastic six-pack holders.

Finally, avoid chemical pesticides as much as possible. “If the population of birds continues to plummet like it is, there may not be any more birds to watch,” said KTUU.com television in Alaska.

To help study bird populations and patterns, one can join the Audubon Society Christmas Bird Count that takes place across America Dec. 14 through Jan. 5. This year will be the 120th count. The U.S. is divided up in 15-mile diameter circles. One joins an existing circle and counts birds in that circle on a specific day. There may not be an existing circle in your immediate area, though.

The Great Backyard Bird Count sponsored by the Audubon Society and the Cornell Lab of Ornithology is conducted over President’s Day weekend in February. One counts birds in ones own backyard each day and enters the results online.

For more information on either of the bird counts and to sign up, visit aububon.org. To read the whole report “Decline of the North American Avifauna, visit ScienceMag.org.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
PLEASE TURN OFF YOUR CAPS LOCK.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.