Hudsonian Godwit Migrations

One of the great mysteries of the natural world is the way various shorebirds make their incredible migrations. One of the most studied shorebirds gets part of its name from Canada’s Hudson Bay, where it was first identified. The second part of its name comes from its two-syllable cry of “god-wiiit.” The Hudsonian godwit (Limosa haemastica) is a bird with remarkable migrations.

Hudsonian godwits lay their eggs in Alaska and northern Canada in the spring. Then, in June or July, they leave their hatchlings to fly 4000 miles to the northern Amazon. After that, they make another 2000 mile flight to Chiloé Island off the coast of Chile. Then, the following spring, they fly 6000 miles from Chile to the northern areas where they lay their eggs and repeat the cycle. 

A mystery is how the young Hudsonian godwits make their journey without adult instruction about where to go. Since these birds live ten to twelve years, they will make the journey as many as 24 times. Hudsonian godwits weigh less than an ounce when they hatch, but in a couple of hours, they are running around catching mosquitoes and flies. Then, before starting their journey south, they bulk themselves up to more than 12 times their original weight. 

Another mystery about the birds is their anatomical preparation for the flights. A typical Hudsonian godwit will have blood sugar concentrations that would be in the diabetic range for humans. Before their migration, the birds’ pectoral muscles double or triple in size, as do their hearts and lungs. To balance this increase, their gizzards, livers, and kidneys shrink. When they arrive at their destination, all of their organs readjust to the normal range. 

As the birds fly their long journeys, one side of their brain will sleep while the other side stays awake and alert, and later the sides will switch. It is called uni-hemispheric slow-wave sleep, and it allows them to fly day and night. In addition, their respiratory systems are highly efficient, allowing flight at high altitudes with less oxygen. That is essential since they fly over the Andes Mountains. 

Also mysterious is the ability of Hudsonian godwits to navigate their journey. Researchers say the birds know and understand weather systems, including wind and rain. They navigate with their vision using stars and landforms, and even smells seem to guide them. But that still does not explain it all. They also sense Earth’s magnetism, but scientists are not sure how. One hypothesis is that their vision is linked to Earth’s magnetic lines of force by “quantum entanglement,” a phenomenon Einstein called “spooky action at a distance.” 

The journey of Hudsonian godwits allows them to secure food at random locations, and their diet of mosquitoes, insects, and worms benefits the environment as much as the birds. The design of Hudsonian godwits speaks of wisdom, planning, and highly sophisticated applications of physics. It would seem that understanding these birds should inspire wonder in a thinking person about the source of such abilities. Truly “we can know there is a God through the things He has made (Romans 1:20.) 

— John N. Clayton © 2022

Reference: “The Wonder Bird” in Smithsonian magazine January/February 2022.