The Pacific Ocean is a large and overwhelming body of water that would discourage even some of the most prolific navigators from trying to cross it without stop – and especially without too many resources. Yet, the bar-tailed godwit, a large migratory bird that winters on the coasts of Australia and New Zealand and breeds on the Alaskan coasts and tundra, makes the journey from Alaska to New Zealand and back on a yearly basis, traveling across thousands of kilometers, often without stopping even for rest or nourishment.
Bar-tailed godwit were observed by scientists through satellite tags as they departed from the shores of New Zealand and made their way northward. One of the bird actually managed to cut a path straight through the Western side of the Pacific Ocean, to wetlands on the North Korea-China border. The journey, taking almost a week and covering a distance of about 10,200 km, was completed without stop. After feeding and resting, the bird completed the rest of its 3,000 mile journey to Alaska without a stop. The longest distance ever traveled by a migratory bird was also covered by a bar-tailed godwit. Observed on its long southward trek, the bird flew straight from Alaska to the shores of New Zealand for 8 whole days, without needing to stop for rest or nourishment.
The bird itself doesn’t look as impressive as it truly is. This magnificent traveler is about 40 cm long, bill-to-tail, and is a relatively short legged species of godwit. They can weigh anything from 200 to about 630 grams – the females of the species usually being slightly heavier – and adult godwits feature a two-colored bill and blue-gray legs. Quite similar to the Asiatic dowitcher, the bar-tailed godwit can easily be distinguished from black-tailed godwits due to a consistent stripe, or bar, present on their tails, as opposed to the wholly black tail of the latter.
The fact that the bar-tailed godwit can display an incredible show of endurance through its straight flight of thousands of miles is undeniable. But what are the real energy costs of such a journey? A bar-tailed godwit is able to maximize its efficiency during flight through a combination of increased endurance, the use of favorable winds through the center of the Pacific and – somewhat surprisingly – its avoidance of any stops. Scientists say a flight with many more stops would actually require a far greater amount of energy due to the increased energy expenditure needed for departure. As such, many researchers who have studied the bird believe that its path carved straight through the heart of the Pacific Ocean may actually be one of the most efficient routes it can take.
The timing of the bar-tailed godwit’s flight is considered to be essential to the successful reach of its destination. Cyclones forming in the northwest Pacific gradually move eastward, toward Alaska, allowing for favorable winds to aid in the bird’s flight during its initial start. What’s curious, however, is that the birds generally fly a straight path when crossing the Pacific Ocean southward, and follow a continental path on the way back. Researchers assume this behavior to be consistent with the lack of any possible stop for the last 4,000km of the journey. Without a doubt, this high endurance bird is quite unique among the migrating birds of the world.