GPS loggers can give a bird's position to within a few yards. Some loggers also have temperature sensors. By attaching them to the legs of their study birds, scientists can tell when the birds are flying and when they are resting or feeding on the sea, because the water is generally cooler than the air. As nifty as GPS loggers are, there is a snag: you have to get them back—an outcome by no means guaranteed. Among the larger albatrosses, chick-feeding forays can last ten days or more and encompass thousands of square miles of ocean.
Lots of things can go wrong on these outings, particularly in and around commercial fishing grounds, where birds die by the thousands, done in by hooks, nets and the lines that haul them. And because albatrosses have to struggle to take flight in the absence of a breeze, birds may be becalmed on the sea. The Chatham albatrosses' feeding forays tend to be relatively short—only a few days—and there was little chance of his birds becoming becalmed in the windy latitudes they inhabit, meridians known to mariners as the Roaring Forties, Furious Fifties and Screaming Sixties.
More worrisome to Scofield was the knowledge that the area adjacent to the Chatham Islands—known as the Chatham Rise—is one of New Zealand's richest commercial fishing grounds, replete with orange roughy and several other deep water species. Albatrosses, too, know where fish are found, and the birds sample the most productive fishing areas much as human shoppers make the rounds of favorite stores.
And what expeditions these birds make! From mollymawks, as the smaller species are known, to the great albatrosses, these super-soarers cover tens of thousands of miles in their oceanic forays. Individuals of some species circumnavigate the globe, covering miles a day at sustained speeds of 50 miles per hour. And then they somehow find their way home—even when home is an outpost in the ocean like the Pyramid, not much bigger than an aircraft carrier.
At the start of their breeding season, albatrosses have been tracked making almost ruler-straight trips from distant foraging areas to their nests. Because the birds maintain their course day and night, in cloudy weather and clear, scientists believe they use some kind of magnetic reckoning to fix their position relative to the earth's magnetic field.
The birds also seem able to predict the weather. Southern Buller's albatrosses were found to fly northwest if a low-pressure system, which produces westerly winds, was imminent, and northeast if an easterly wind-producing high-pressure system prevailed.
The birds typically chose their direction 24 hours prior to the arrival of the system, suggesting they can respond to barometric cues. In his autopsy room in Wellington, ornithologist Christopher Robertson slit open a plastic bag containing a white-capped albatross. The swan-sized carcass had been thawing for several days. Along with dozens of other seabirds in Robertson's freezers, this one had been collected at sea for the government's fisheries science program.
Robertson carefully unfolded the bird's wings—wings that would have carried it halfway around the world, between its breeding grounds in New Zealand's Auckland Islands and its feeding grounds in South African seas. The albatross bore a raw wound at the elbow.
Its feathers and skin had been rasped down to bare bone, presumably by the thick steel wires—called warps—that pull a trawl net. Of the 4, albatrosses and other seabirds Robertson's group has autopsied over nine years, nearly half have been killed by trawl fisheries, which use giant sock-shaped nets towed at depths of a quarter mile to capture 40 tons of fish in a single haul.
Albatrosses and other large, soaring birds tend to die as a result of collisions with the warps, while smaller, more agile fliers such as petrels and shearwaters are more likely to get ensnared in nets—to be crushed or drowned—while feeding. The finding has surprised the fishing industry and conservation groups, which have considered longline fishing—in which thousands of baited hooks are fed out behind the fishing vessel—a greater threat to seabirds.
There are no reliable figures for the number of birds killed per year through contact with commercial fishing operations, but estimates for the Southern Ocean are in the tens of thousands. Vessels in well-regulated fisheries are required to minimize their impact on seabirds and report any accidental deaths, but there is a large shadow fleet of illegal, unregulated and unreported IUU vessels operating outside the regulations, answering to no one. Many New Zealand fishers have adopted ingenious methods to reduce injuring and killing seabirds—or attracting them to boats in the first place see sidebar, opposite.
However, there is some evidence to suggest that fisheries may benefit albatross populations: a ready supply of discarded fish reduces competition for food between and within albatross species and provides an alternative food source to predatory birds such as skua, which often attack albatross chicks. Afterwards chicks are left unguarded, except for feeding visits, until they fledge at about eight months.
This helps the nestling build her flight muscles for the day when she leaves the nest in September, heading off on her own to feed over great stretches of the Pacific Ocean and not touching land for several years. After successfully raising a chick, the parents leave the colony to spend a year on their own feeding at sea.
After a year off they will return to breed again, completing a two-year cycle. Adolescents return to look for a mate after 3 to 8 years on their own. Once back at the same breeding grounds they left years earlier, the male birds make a display of stretching their wings, lifting their heads, and screaming raucously. All in an effort to catch the eye of an admiring female, to be followed by elaborate courtship rituals. Male birds all over the world and males in general!
Learn more about some of the tricky dances and demanding songs in my article on sexual selection : Why Are Male Animals More Beautiful and Colorful? Sexual Selection! With Photos. For a wonderful wildlife viewing experience, we can highly recommend the friendly and informative Monarch wildlife cruise. We slowly drifted alongside albatross feeding on the ocean surface without bothering them and had lots of excellent photo opportunities.
The captain took the boat in close for a great view of NZ fur seals on the rocks and in the water around their breeding rookeries. When the weather was cool and unsettled on our trip, they provided us with cozy waterproof jackets. Richardson, P. Progress in Oceanography 88, Flight speed and performance of the wandering albatross with respect to wind.
Mov Ecol 6, 3 Rattenborg, N. Evidence that birds sleep in mid-flight. Nat Commun 7, Header photo of albatrosses riding gale-force winds on the open ocean by Fer Nando on Unsplash, with thanks. George Sranko, B. He has explored fascinating nature topics and epic destinations for over 40 years, beginning with his first job as a National Park naturalist. George is a popular destination and science lecturer on cruise ships throughout the world, with hundreds of presentations under his belt.
He has visited over 90 countries and happily shares his personal experiences and insights in a dynamic and entertaining style. Whenever I listen to the song of a Humpback whale, I am captivated by the eery quality of the complex sounds. Electric eels can produce volt electric pulses up to times per second. These high-voltage pulses are so strong that they remotely activate the neurons inside the prey, making their Skip to content. Albatross flight is an excellent example of how birds can use air currents and thermals to soar long distances without exhausting themselves or expending much energy.
SWA and gamma power were estimated from Fourier coefficients taken for ranges 0. Medians of SWA and gamma power were used for statistical comparisons. Quartiles for group medians shown in Fig. Interhemispheric asymmetries in SWA and gamma, and their relationship with the mode of flight Fig. In addition, SWS-related SWA was calculated for the last night of flight to detect potential changes in sleep intensity across the flight Supplementary Fig.
The accelerometer recordings revealed two predominant patterns during flight Fig. In contrast, during gliding and soaring flight, the three axes were largely flat or showed slow oscillations likely reflecting a combination of fine manoeuvres and respiratory movements see expanded view for SWS in Fig. When gliding and soaring during the day, small, frequent and rapid horizontal movements of the head were superimposed on these slow oscillations. Flight was occasionally interrupted by a rapid decrease in acceleration along the heave axis, corresponding to the bird dropping, presumably due to momentary folding of the wings Supplementary Movie 4.
Finally, bouts of high-frequency activity occurred infrequently in all axes simultaneously, likely reflecting preening, as observed in birds flying over the colony and while on the nest.
Previous studies 12 , 13 , 26 and our own observations Fig. In addition to identifying flapping flight, the accelerometer was useful for discriminating circular from straight flight Fig.
Thus, the tangential co-directed with the speed vector acceleration is zero in both flight modes. As rotation lies approximately in the horizontal plane, the two acceleration vectors are orthogonal to each other and total acceleration,. Thus, to determine whether the trajectory is straight or not, it is sufficient to measure total acceleration, low-pass filter it to remove the influence of wing flapping and compute radial acceleration from this equation.
Radial acceleration above 0. Total acceleration in circling flight was 1. However, for our EEG analysis it was also important to know whether the bird was rotating to the right or to the left. Because frigatebirds keep their heads straight during both flight modes, we were able to determine radial acceleration directly from the accelerometer without additional transformations.
However, to confirm this claim and to increase the accuracy of the radial acceleration measurements we also performed computations without this assumption. The accelerometer was attached to the bird's head in a way such that one axis was orthogonal to the tangential plain of the bird skull and another was directed laterally. Projection of total acceleration on to the tangential plain of the bird skull clearly shows three clusters corresponding to straight and circling flight, with turning to the left and right see data from one example bird in Supplementary Fig.
To simplify this analysis, we rotated the axes of the head-fixed coordinate system to have one axis directed to the ground during straight flight; however, in the recording examples shown in Figs 2 and 3 , Supplementary Fig. The following analysis shows that the skull surface tangential plane deviated by We then filtered out high frequencies by applying a low-pass finite impulse response filter 0. The input data were processed both in the forward and reverse directions and the resulting sequence had precisely zero-phase distortion and doubled filter order.
Then, we computed principle components PCs in 3D space without mean subtraction. The first PC pointed in the direction of the gravity vector, the second—in the lateral radial direction, and the third—in the direction of the speed vector. In the horizontal plain of the second and the third PCs Supplementary Fig. The best separation was observed along the second PC corresponding to sway acceleration.
Because we wanted to compute rotations of the head relative to straight flight, we repeated the PC analysis, but for points representing straight flight only. Coordinates of the first PC gave the direction to the ground during straight flight. The angle between this direction and skull surface normal is the skull angle shown in Supplementary Table 1. We rotated the coordinate system a second time to have one axis in the direction of the first PC Supplementary Fig. In this head-fixed coordinate system, during circling flight, the absolute value of lateral sway acceleration was 0.
Assuming zero tangential acceleration as before, we computed the angle of the head turn in circling flight 2. To simplify interpretation of the head turn we computed angular deviations of the head-fixed vector pointing upwards in the lateral right—left and anterior—posterior beak—tail directions.
These deviations were 1. As shown in the table, bank angle wings-to-horizon was computed with the assumption that total acceleration was orthogonal to the plane of the wings. This assumption was verified by placing accelerometers on the backs of two magnificent frigatebirds together with the GPS logger in a pilot study Supplementary Fig. In these two birds, total acceleration during circling flight was 1. Standard deviations of sway acceleration were 0. Thus, the standard deviation of the total acceleration vector in the lateral direction was 0.
These angles are much smaller than the angle of the wing plane to the horizon Thus, our assumption about orthogonality of the plane of the wings to total acceleration is correct. Wing flaps and drops were detected by analysing the absolute values of the acceleration vectors recorded by the accelerometer.
Then the signal was band-pass filtered 0. The point fragments of the record centred around the detected acceleration minima were sorted using wavelets and a superparamagnetic clustering algorithm 37 WaveClus 2. After validating the classification algorithm and cluster matching in two birds, the recorded fragments from the remaining birds were sorted using a faster and simpler nearest neighbour algorithm computing and comparing distances from non-classified elements to the members of the clusters already classified in bird 1.
The average shapes of acceleration around flaps, drops and noise are shown in Supplementary Fig. Flaps produce pseudo-periodical deviations in total acceleration with negative and positive deviations of approximately similar magnitude. These almost sinusoidal deviations are produced by regular up—down wing movements. Contrary to flaps, drops are characterized by a strong negative deviation followed by a slow positive compensation.
They are produced by momentary folding of one or both of the wings see Supplementary Movie 4. Noise is characterized by smaller deviations around the zero time point and on average has a symmetrical shape relative to the zero time point. The distribution densities of the maximal deviation of acceleration at zero time shown in Supplementary Fig.
However, separation of drops from flaps and noise required information about the signal shape. Wind information absolute value and direction at the birds' location was obtained from the Movebank database www. Quantities expressed as a per cent were first normalized using a Fisher transformation. For the analysis of the relationship between sway acceleration and EEG asymmetry Fig. The authors declare that the data supporting the findings of this study are available within the article and its Supplementary Information Files , or from the corresponding authors upon request.
How to cite this article: Rattenborg, N. Evidence that birds sleep in mid-flight. Confronting the winds: orientation and flight behaviour of roosting swifts, Apus apus. B , — Article Google Scholar. Harmonic oscillatory orientation relative to the wind in nocturnal roosting flights of the swift Apus apus.
PubMed Google Scholar. Dokter, A. Twilight ascents by common swifts, Apus apus , at dawn and dusk: acquisition of orientation cues? Liechti, F. First evidence of a day non-stop flight in a bird. Gill, R. Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier? Klaassen, R. Great flights by great snipes: long and fast non-stop migration over benign habitats. Bairlein, F. DeLuca, W. Deppe, J. Natl Acad. USA , E—E Ouwehand, J. Alternate non-stop migration strategies of pied flycatchers to cross the Sahara desert.
Ashmole, N. The biology of the wideawake or sooty tern Sterna fuscata on Ascension Island. Ibis b , — During the nestling period of a single egg, which mates take turns caring for and can last up to 10 months, Wandering albatrosses for example here , return to sea to look for food, while the other mate stays on the island with their chick here.
Due to their unique flight mode further reading about this can be found here: here , here flight recordings have shown that albatrosses are indeed capable of flying up to 10, miles in a single journey and circumnavigate the earth in 46 days here.
Missing context. This article was produced by the Reuters Fact Check team.
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