Tag: bird migration

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Insect Migrations and Earth’s Ecosystems

Insect Migrations and Earth's Ecosystems
It is spring in the Northern Hemisphere, and one of the joys of spring is seeing the amazing migrations of birds as they move north from their wintering grounds. We watch the birds without thinking of the logistics that are involved in millions of birds moving over fast distances. How do you feed these hordes of living things? Their needs are even greater than usual because of the energy required for the long flights. We may not realize the importance of insect migrations that occur at the same time. What collateral benefits does this system create?

Dara Satterfield of the Smithsonian Institution in Washington, D.C. says, “Trillions of insects around the world migrate every year, and we’re just beginning to understand their connections to ecosystems and human life.” This migration not only feeds birds, but they pollinate wild plants and gobble agricultural pests.

We have written in our quarterly journal about the spring migration of monarch butterflies from Mexico to North America. In Europe and Africa, the migration is even more amazing and complex. Each spring the painted lady butterfly travels from Africa across the Sahara desert and the Mediterranean Sea into Europe and then retraces that journey in the fall. Because their life expectancy is so short, it takes six generations of butterflies to accomplish this migration. The butterflies avoid the extreme heat of North Africa in the summer, but they arrive in Africa just in time to feed from the flowers in the fall. Those butterflies are vital to the balance of living things in Europe.

Some of the insect migrations are very important to human food production. The marmalade hoverfly eats aphids during the larvae stage, and as adults they pollinate plants. The volume of insects is seen most clearly in the Pyrenees and Alps. Millions of hoverflies use the winds blowing through the mountain passes to get from one place to another. Scientists have been monitoring this migration because of its economic importance to agriculture in Africa and Europe. There is also a hoverfly migration in the western United States, but it has not been studied.

The size of these insect migrations is hard to comprehend, and we fail to understand the complexity of this system. Studies in the southern United Kingdom estimate that 3.5 trillion insects migrate over that area every year. Without those insect migrations, ecosystems on this planet could not exist.

Those of us who believe in God’s design of the creation see this as one more evidence that the simple statement “In the beginning God created the Heaven and the Earth” is a massive oversimplification. We truly can “know there is a God through the things He has made” (Romans 1:20).
–John N. Clayton © 2018

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Bird Migration Data

Bird Migration Data
A fascinating area of study is bird migration. With new technologies, scientists are gathering more bird migration data than ever before.

Arctic terns spend their summers in Alaska and migrate thousands of miles to wintering grounds in South America. Years ago researchers demonstrated that the tern didn’t get the migration information from its parents because terns raised in isolation having no contact with other terns could still make the journey. Terns deprived of visual acuity could still make the journey, so the migration was not by landmarks. The Earth’s magnetic field was not the method because terns equipped with a magnetic scrambler could still make the journey. Similar tests showed it was not by smell or by sound. The researchers concluded that the tern used several navigation tools. If one was lost, the bird would switch to another. We suggested that such a complex system was not a product of chance. It is designed into the tern’s DNA suggesting that God had something to do with the design.

In the March 2018 issue of National Geographic, there is an excellent article titled “Epic Migrations.” Scientists use new tools to collect bird migration data that enables a much more precise understanding of both short and long migrations. Nearly half of all bird species are migratory, so there are a large number of species to study, and scientists are gathering new data continuously.

The long-distance winner of migration is the bar-tailed godwit. One specimen flew 7,150 miles non-stop in eight days from its summering grounds in Alaska to its wintering grounds in New Zealand. In the weeks before migration, godwits build up enormous layers of fat adding more than half their body weight. When they arrive in New Zealand, they have lost all of the fat reserves. Because they do not glide or soar in the journey, their wings are beating all the time. On the way back to Alaska, the birds travel 6,000 miles to China near the Yellow Sea where they spend six weeks. Then they fly 4000 miles back to Alaska. Their departure time for these trips is the same from year to year, influenced only by local weather and winds. They seem to be guided by a precise clock.

Researchers have found an assortment of interesting bird migration data. Studies of frigatebirds in the Pacific show that they sleep while soaring, but only for about 12 seconds at a time for a total of 42 minutes a day. Research shows that half of the bird’s brain is asleep and the other half is awake. Other studies have shown that European starlings use the Sun as a compass and that indigo buntings use stars as a compass. European robins use an internal magnetic compass. When researchers artificially rotated the magnetic compasses by 90 degrees, the birds flew the wrong direction until the Sun came up. Then they reset their magnetic compasses using the Sun for orientation.

Each species of migratory birds seems to have their own built-in devices to make their journeys. The programming of their DNA is incredibly complex and seems to be a designed characteristic built into each species. We can learn a great deal about God by observing the world around us, and truly “we can know there is a God through the things He has made” (Romans 1:20).
–John N. Clayton © 2018