During the summer months, many of us spend more time outside, perhaps stargazing or enjoying time on a boat. Can you imagine the skills and knowledge of ancient mariners as they crossed the seas using only the night sky for navigation? Thank goodness for GPS and radar for us modern humans! Amazingly, many animals utilize the sky to travel long and far, arriving at their planned destinations. How do we know their destinations are deliberate? Many arrive at the same location year after year, whether looking for nesting spots, mates, or food. For animals that travel by sea, by air, and even under water, the night sky is essential for navigation and survival. Why does it affect their ability to survive, you may ask? If they cannot find each other to mate…the population will cease to exist.
According to Audubon, 70% of birds in North America migrate and over 80% of them make their seasonal flights at night. By traveling at night, birds experience calmer air, less predators, and cooler temperatures which can help prevent overheating. By avoiding day time heat thermals, it is also easier to maintain a steady course. Canada geese, buntings, warblers, and thrushes are just some of the species that are night migrants. Blackpoll Warblers travel nonstop more than 2, 000 kilometers from the northeastern United States to winter in the Caribbean islands. Some species like the Swainson’s thrush can shut off half its brain allowing it to sleep while flying.
Animals orient themselves by identifying the starry sky’s center of rotation, which is found at the earth’s orbital poles; and then determine their direction by observing the rotation of close star patterns around a center point, such as the North Star. Multiple studies in various planetariums showed that birds learn north-south orientation from a rotational star pattern.
Horseshoe crabs rely on moonlight for their nocturnal activities, including mating and spawning, which occurs during the full and new moons in May and June. These prehistoric creatures have a total of ten eyes, including light-sensing organs on its tail (telson), which keeps their brains synchronized with cycles of light and dark, and can detect ultraviolet light from the sun and reflected light from the moon.
Many marine animal species migrate great distances in vast oceans, and celestial cues could be useful as these long passages lack terrestrial landmarks.
To learn about how you can support our wild celestial navigators, enjoy this 26 minute informative video created by Southampton Town Dark Skies Committee, ‘starring’ some local folks and places that you may know!
by Marisa Nelson