12 October 2019

Global warming contributing to mass disappearance of bird population in North America, says Professor Mark W. Harris

In September, Science Magazine published a report on the status of bird species populations and diversity.  The shocking report, which was published in summary by the New York Times, Cornell University Laboratory Of Ornithology and many other organizations, provides scientific data proving the disappearance of populations of birds in North America by comparing radar data from 2017 with that of 1970 showing the biomass of birds or insects in the atmosphere throughout the period. 

The total population of birds in North America has decreased by 2.9 billion (29%) in just 50 years. A German study showed an 83% decrease in insects in summer months using similar weather radar data analytics. In 2019, one million species of plants, insects, birds, mammals, and amphibians are in imminent danger of extinction. 

To explain the direct evidence of impact from global warming, Professor Mark W. Harris, provides examples from personal observations as a citizen scientist.

“In 1964, I began a journal recording my observation of birds by date, location, species and number of birds.  Since 1993, I have reported my data to Cornell Laboratory of Ornithology, which conducts research on the behavior, population and range changes, nesting and migration of all species of birds," shares Professor Harris. Below are two concrete examples of global warming impacting birds observed by him:

Extreme Weather Destroying Nests

The polar ice caps and glaciers are melting.  This result of global warming is raising sea levels around the world. More noticeable is the frequency and greater destructive power of tropical storms, which is empowered by warmer seawater temperatures.  These are felt around the world.

In the 1960’s, Professor Harris observed nesting colonies of terns, gulls, and plovers who laid eggs in nests on the sand just above the high tide lines on Nauset Beach in Massachusetts.  Four species of terns nested just above sea level: Common Tern, Arctic Tern, Roseate Tern, and Least Tern. More than 5000 nests produced more than 10,000 eggs and chicks.

Today the colony is gone.  Super high tides have swept over the secure sand peninsula where few humans went.  Summer storms, storm surges, and violent Northeaster storms washed out the nests before eggs can hatch and the teens abandoned this area.  Other shore nesting species: Snowy Plover and Piping Plover are threatened with extinction due to these and other hazards associated with global warming. Arctic Tern (famous for migrating 20,000 miles per year North to South) is an endangered species.

Southern Species Moving Their Ranges Northward

"Whenever possible, my brother Jeffrey, who led wildlife tours for the Audubon Society in the 1960’s, and I 'go birding'. We inventory birds, identifying species and their numbers by specific (geo co-ordinate) locations. At the end of one such day in November 2018, we looked at the results of our day inventory over coffee," Professor Harris describes. They remarked that half of the species on the list were species that were scarce in Massachusetts in the 1960’s and the nesting grounds of those species did not reach as far north as Massachusetts. They had replaced many species that had taken their place in the ecosystem: Carolina Wren taking over from House Wren, Foresters Tern taking the place of Arctic or Roseate Terns, Mockingbird taking the role of disappearing Brown Thrashers, Egrets replacing Herons."

Some of the former species retreated further north, but most declined in population altogether, including formerly burgeoning populations of introduced species like House Sparrow and European Starling.

Other Human Infrastructure Affecting Millions of Birds Each Year

Each year in the USA alone, 1 billion birds fly into glass windows of high rise windows attracted to the light during migration (at night).  However, recent attempts by scientists collaborating with office building owners, like the new World Trade Tower in New York have been successful in extinguishing electric lights during specific hours on nights when weather and winds anticipate significant migration. 

Wind turbines are also kill migrating birds: in the USA 328,000 in 2013 were estimated to have been killed.

The Cornell Lab of Ornithology suggests 7 simple actions to help birds, such as making windows safer, keeping cats indoors, reducing law and plant natives, avoiding pesticides, drinking coffee that is good for birds, protecting our planet from plastic, as well as watching birds and sharing what you see.