Birding Today — Frigatebird have unusual sleep habits

The Magnificent Frigatebird that was seen over Oklahoma’s Lake McMurtry only two years ago has been seen over more and more land mass as time progresses.

The frigatebird is one of the most astonishing masters of flight, but it is no easy task. Even though they haven’t the range of the Eurasian Alpine Swift, the Great Frigatebird can remain in flight for nearly two months without touching down. Even more amazingly, they cannot swim since their feathers become weighty with water. It was then learned that it has to do with sleep requirements, which has been an indicator for some birds for years.

Due to observation and research, nesters in the Galapagos became easy to work with over time periods. EEG implants were consulted, which proved when they were asleep or awake, while the accelerometer provided directional and speed data.

Common knowledge for some avian species, some sleep for mere seconds at a time with one side of the brain. Without natural predators to remain awake for, the likely reasoning was to avoid colliding with others of the species.

It was learned that out of the nearly one hour of daily sleep, it occurs mainly after darkness falls while the frigatebirds are in flight. While on land, the sleep time is considerably greater for up to a minute at a time through the day for about half the 24-hour period.

Another travel method that is an uncommon plus is the fact that the Great Frigatebird can ride highly-powered thermals within cotton candy-like cumulus clouds thrusting them over 10 feet a second, which means that our normal short distance flight of one mile is dwarfed by this two and a half mile cruising rate.

Like many of our thermal pilots, the long-standing biological data shows that several birds sleep while in flight, like the albatross, condor, and more. Even the Mallard provided initial data of why humans are unable to sleep well away from home, simple because half of our own brains are not as refined as birds’ abilities. Next time one hears that birds don’t have as much intelligence as the larger brained species, guess again. They are some of the most long-lived animals in the world.

The common Turkey Vulture rides upward warm air currents, which allows them to stay closer to terra firma than other carrion aficionados. This technique is called contorted soaring since the air currents collide with treetops.

For those that remain unimpressed with our health engineers, not only do Turkey Vultures keep us away from unhealthy pestilence on the ground by ingesting it, they counteract wind forces by rocking from side-to-side in both turbulent as well as light wind speeds.

American White Pelicans use the classic “V” formation of geese to save energy during their migration. Their reliance upon thermals and updrafts during spring changes to tailwinds in fall when air currents are weaker. This is another case for avian resilience and longevity.

The Magnificent Frigatebird that was seen over Oklahoma’s Lake McMurtry only two years ago has been seen over more and more land mass as time progresses. Is this expansion or unusual? Only time will tell.  

Deb Hirt is a wild bird rehabilitator and professional photographer living in Stillwater.

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