bird migration Archives

October 15, 2020October 14, 2020

Migrations and Winter Adaptations

There are many things about fall that make it an interesting time of year. It is not just the colors and the cool and pleasant temperatures that make fall special. We also see migrations and winter adaptations.

Bird migrations are amazing, with some species using unique wind patterns to make the journey across the Caribbean. Other birds that spend summers in our area, such as loons, congregate in groups in Florida in the winter.

The most amazing migrations, however, are the smaller forms of life. For example, green darner dragonflies spend the winter in Florida and the Caribbean, where they mate and produce offspring. When the average temperature warms to about 48 degrees F, these offspring fly 900 miles to the north, where they breed, lay eggs, and die. When the eggs hatch, they spend the summer in Canada or Michigan. In the fall, these third-generation individuals return to Florida flying some 900 miles (1500 km) or more over a route that they have never seen before.

When we consider migrations and winter adaptations, we can’t overlook monarch butterflies. They are the most amazing of these multi-generational migrants, with fourth-generation butterflies making a 3,000-mile (4,800 km) flight. There are also insects and amphibians with a blood protein that acts like antifreeze, allowing them to be frozen solid without damaging their cells.

There seems to be no limit to the way animals can adapt to winter, and sometimes these adaptations change. In our area, Canada geese used to all migrate to southern latitudes to spend the winter. With the advent of power plants that keep some rivers and lakes free of ice, that has changed. A sizable population of Canada geese remains in our area of Michigan, Wisconsin, and Minnesota all winter long. We have had as many as 200 geese crowding open water near a power plant in the St. Joseph River during the coldest days of winter. That didn’t happen in 1959 when I moved to this area.

These patterns of migration and winter adaptations are difficult to explain as accidental. It would seem that the animals have had a designed genetic program to allow them to survive. The design is fascinating, and the Designer is even more amazing. We praise God as we watch the magic of migrations and winter adaptations.

Data from “On Nature” by Sheryl Myers, The Herald Bulletin, October 3, 2020 page B3.

April 24, 2020April 23, 2020

Why Do Birds Fly North in Spring?

We all understand why birds of the Northern Hemisphere fly south in the fall. When the temperatures drop in Michigan, and the lakes are covered with ice, most birds have found a warmer place in the south. Michigan has many so-called “snowbirds” in the human population who leave us in November to go to Florida’s sunny shores. They come back in the spring to enjoy Michigan summers and because they have family here. The question is, why do birds fly north in spring? Couldn’t they save a lot of trouble by just staying in the south all year?

The answer to that question is food. The fact is that tropical areas simply don’t have enough insects to provide the protein that birds need to feed their chicks. When birds are in the south, they survive by eating berries, fruits, and nectar. None of those foods provide much protein. The time when birds return to the north coincides with the explosion of insects in the spring. They can enjoy less competition and longer days while dining on insects in the north.

The question remains as to how the birds know this? How do they know that they can benefit by traveling hundreds or thousands of miles in the spring? Why do the birds have the urge to fly north at the time that benefits them as well as the ecological systems they help to support? In other words, why do birds fly north in spring? The answer is that it’s built into their genes.

God’s view of Earth and the systems that make it work is far greater than ours. We are beginning to understand how many things, such as bird migration, must happen for the system of life to exist. It also speaks to us about how important it is that we take care of what God has given us.

Reference: Smithsonian magazine, May 2020, page 88.

April 23, 2018November 8, 2018

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

March 27, 2018September 7, 2018

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