Who really said that?
The admonition was first used in 1851 by John Babsone Lane Soule in the Terre Haute Express. It resonated with Greeley, who rephrased it for a 1865 New York Tribune editorial: "Go West, young man, and grow up with the country". That phrase captured the imagination of many, including soldiers returning from the Civil War. As a result, throngs of people traveled west to homestead.
Homesteads are currently available in several states, including here in Tennessee.
Birds are changing physically
In an apparent response to climate change, the body size of migratory birds in North America have been shrinking. And over the past 40 years, wingspans have increased.
Since 1978, Field Museum staff and volunteers in Chicago have retrieved dead migratory birds that collided with buildings. The research team analyzed the data, looking for trends in body size and shape. They found that from 1978 through 2016, body size decreased in all species, with marked declines in 49.
Findings published in the journal Ecology Letters during the same period show significant wing lengthening in 40 species.
The numerous consistencies were a surprise, revealing that all birds responded in similar ways. This study is the largest analysis of avian body structure responses to recent atmospheric warming. It noted consistent large responses in a variety of bird groups.
(satellite view of the massive Caldor Fire in California, which has been hard-hit by wildfires this year. To date, 7,099 fires have burned 1.9 million acres)
Connection between bird size and climate
Researchers measured 70,716 birds during the study. Evidence indicates a causal relationship between warming temperatures and declines in avian body size. Cooler temperatures resulted in size increases.
The strongest evidence suggests that numerous short-term fluctuations in body size synchronize with temperatures. Periods of rapid warming are followed closely by a decline in size.
Within animal species, individuals are normally smaller in warmer parts of their range, a well-known effect called Bergmann’s Rule. And while the possibility of size reduction due to global warming has been hypothesized for decades, supporting evidence remains inconclusive. This may be partially attributed to the lack of any available datasets other than the Field Museum study.
Studies of plant and animal responses to climate change frequently focus on shifts in geographical range or the timing of certain events, such as spring blooming and migration. The consistent decline in body size noted in the study suggests that these kinds of changes should also be added to the list of challenges faced by wildlife in our rapidly warming world.
It became clear to researchers that changes in body size and shape are likely to interact with changes in range and timing to determine how well a species can respond to climate change.
Long-distance migration is considered one of the most impressive feats in the animal kingdom. For example, Arctic Terns migrate from the Arctic Circle to the Antarctic Circle each year, a round-trip of about 18,641 miles.
Approximately half of the world's nearly 10,000 documented bird species migrate.
The extreme amount of energy required to fly thousands of miles has influenced the form and structure of migrating birds in order to produce the most efficient flight. Body size reductions are a response to the warming climate. Increased wing length may help offset the loss of body mass.
Birds analyzed in the study were small songbirds that breed north of Chicago in the summer, migrating through the region in large numbers. Several species of warbler, sparrow, and thrush composed the majority of specimens, and thousands of individuals of each species were documented as lethal collisions.
The observable changes in avian body size and shape are extremely subtle and undetectable with the naked eye. They're no more than a couple of grams of weight and a few millimeters in wing length.
Drought means a lack of food
Severe drought is expanding across the Great Plains and Upper Midwest. Migratory birds are facing drought, disease, and death along the Pacific Flyway.
Millions of birds migrate through the basin each year, relying on a system of wildlife refuges that are quickly drying up. Last year, drought conditions forced too many birds into areas too small to hold them. As a result, 60,000 died from avian botulism. Experts predict this year will be worse.
(above: 2002 photo of Kesterson National Wildlife Refuge in the Pacific Flyway; below: its current condition as a result of agricultural runoff)
What you can do to help
The problem is daunting; however, there are ways anyone can help. Feeding wild birds is usually discouraged because it encourages dependence on humans and lessens their ability to forage. However, in the middle of the current extreme conditions, it has become necessary.
A large, Made in USA feeder that holds 8 cups, offers plenty of food for the migrating birds.
Some wildlife agencies warn against offering birds only sunflower seed because it may result in nutritional deficiencies as well as poor bone and feather development. However, birds desperately need available water. Shallow bowls of clean water placed in the shade are one way you can help them immediately. Remember that small birds can drown in deep bowls. Local governments and communities that take a coordinated approach can result in even more available water.
Let grass grow between mowings and don't mow too low. This will increase moisture content and encourage the insects and worms essential to bird diets. Placing mulch or leaves around the garden has the same effect, while at the same time conserving water. Spread grass clippings and build brush piles near your garden. Their moisture will allow insects to survive. Compost heaps are also a good way to cultivate insects.
Create habitat by placing fallen branches around the garden. Heap soil at the base of the pile. If necessary, weigh down with old bricks, broken tiles, or pieces of concrete.
Most importantly, remember that stressed wildlife is on the move in search of food and water. Be extra cautious when driving after dark.