Blog post by PhD student Johannes Krietsch in the Journal of Animal Ecology about a study published in 2020 with pectoral sandpipers in Alaska. The males fly thousands of kilometers through their breeding territory. The researchers wanted to understand whether wind movements opportunistically help to determine the breeding site selection of this polygynous shorebird. Johannes recently won the British Ecological Society Movement Ecology Special Interest Group's MoveMap competition in the "nerdy" category for his visualization of flight movements! Read the full story in his article behind the link.
In order to assess the risk of bats dying at wind turbines, their acoustic activity is recorded with ultrasonic detectors within the operating range of the rotor blades. In a recent analysis, a team of scientists led by the Leibniz Institute for Zoo and Wildlife Research with participation of the MPI for Ornithology concludes that supplementary ultrasonic detectors need to be installed at other locations on larger wind turbines and that additional techniques such as radar and thermal imaging cameras need to be developed for monitoring. The results of their analysis are published in the journal Mammal Reviews: 10.1111/mam.12248
A team of researchers from Aarhus University and our institute was able to record echo and motion data on free-living greater mouse-eared bats in Bulgaria during hunting flight, using recording equipment weighing only three grams. Dr. Laura Stidsholt, a postdoctoral researcher at Aarhus University and lead author of the study, was surprised to find that the bats were guided by extremely weak echoes from prey that would be like whispers to us. "Through the low call intensity, the animals create a kind of "acoustic tunnel vision" for hunting," says Holger Goerlitz, research group leader in Seewiesen. Through the faint sounds, the bats manage to concentrate only on the prey and to actively reduce the interference caused by other echoes.
Migratory birds are small high-performance athletes that have to rely completely on their fat stores during the long distances between breeding and wintering grounds. In a study, scientists from the USA, Poland and our institute wanted to find out which composition of the fatty acids stored in the body is ideal for the long flights. To do this, they placed hand-raised European starlings on different fat diets with monounsaturated (MUFA) or polyunsaturated (PUFA) fatty acids before the birds completed long-distance flights in the MPIO wind tunnel. It was found that the PUFA birds initially consumed less energy, but over the longer term had to cope with more severe oxidative damage than the MUFA animals. The PUFA diet provides a distinct advantage for covering long distances due to the short-term energy savings. To avoid increased oxidative damage, which negatively affects lifespan, migratory birds must adapt their diets by increasing their intake of these special fatty acids only during migration season. Such strategies can also be applied to other vertebrates.
Research group leader Michaela Hau gave this year's Howard Bern Lecture at the annual meeting of the Society of Integrative and Comparative Biology (SICB). This is a special award for scientists who have done significant research in the field of comparative endocrinology. Michaela Hau is honored for her research on free-living great tits, in which she measures stress hormones (corticosteroids) in response to environmental inputs, and the resultant effects on traits such as reproductive success, metabolic rate, behavior, and flight performance. Her research ultimately aims to evaluate how fast physiological systems can evolve.
An analysis of the songs of most of the world’s passerine birds reveals that the frequency at which birds sing mostly depends on body size, but is also influenced by sexual selection. The new study from researchers of the Max Planck Institute for Ornithology and colleagues suggests that habitat characteristics do not affect song frequency, thereby refuting a long-standing theory.
Macaws are capable of using multiple stones to recreate the functionality of a stick tool for accessing a favorite food item. Some of the individuals seemed to check the progress of how far they have pushed the reward after inserting each stone component suggesting that they might understand the causal connection between the stones and the way they connect with each other to push the reward. Lead author Laurie O’Neill says “I was impressed with the successful parrots as they had to make many consecutive actions to build the multi-stone construction required”. The study was realized at the Comparative Cognition Research Station of the Max Planck Institute for Ornithology in Loro Parque Animal Embassy, Tenerife. The scientists involved assume that this behaviour was innovated through trial-and-error learning. Parrots are very explorative and are keen to combine and interact with objects in their environments. This further adds to the evidence that many complex physical behaviours, such as tool-use, could have their origins in more simple behaviours such as exploration. Copyright Photo: Anastasia Krasheninnikova
At the age of four months, ravens already show comparable cognitive performance to that of adult great apes. Under the direction of Prof. Dr. Simone Pika, former Humboldt research group leader in Seewiesen, now University of Osnabrück, the first systematic-quantitative large-scale study of the physical and social abilities of common ravens took place, which also included cognitive development. For example, when Dr. Miriam Sima, who raised the ravens in Seewiesen as part of her doctoral research, hid treats under a cup and moved it back and forth between other cups as in a 'shell game,' even young ravens usually tapped the correct cup with their beaks. The study results showed that the ravens were on par with chimpanzees and orang utans at solving problems, particularly those which involved quantities, causal understanding, social learning and communication.
Songbirds are among the few animal orders that share with humans the ability to learn vocalizations from a conspecific. The neuronal circuits associated with song and speech learning are complex in structure and function. Now a team of scientists from Seewiesen, Munich, Switzerland and Tokyo has come closer to investigating the neural mechanisms of vocal development: They have developed a method with which they can make these brain circuits visible using a fluorescent dye. A detailed analysis of the structures in the bird's brain is possible within just three days of application, which meets the quick pace of developmental learning. The method can also be used to measure in vivo neuronal activity, as the release of calcium becomes visible when a neuron is firing. The researchers hope that the newly gained differentiability will provide novel and more precise insights into the function and development of these circuits and to further our understanding of associated diseases.
Director Bart Kempenaers, head of the Department Behavioural Ecology and Evolutionary Genetics was appointed as honorary member of the world's largest ornithological society. The society thus honors and celebrates his valuable contributions to ornithology and his commitment to science.
More and more artificial lighting at night has consequences, especially for nocturnal wildlife that is not adapted to such high light levels. This influences many aspects of behavior such as foraging, commuting or mating. Scientists of the Research Group Acoustic and Functional Ecology now show in a new study that artificial light at night can also have fatal effects on moths. Many moth species can hear in the ultrasonic range and make various, often successful, evasive maneuvers in flight when they sense an approaching, hunting bat. Although this predator-prey interaction is triggered by sound, the study shows that a light-polluted night sky can suppress the evasive flight behavior of moths. Even if occasionally last desperate maneuvers are carried out, the artificial light could severely reduce the moths’ capability to avoid bats, and ultimately their survival.
Image © Christophe - stock.adobe.com
Sleep in mammals is composed of two major states, non-rapid eye movement (NREM) sleep and REM sleep, a paradoxical state with wake-like brain activity. In many mammals, after cooling during NREM sleep, the brain warms up during REM sleep, potentially preparing it to perform adaptively upon awaking. Researchers from the “Avian sleep” group in collaboration with researchers from the Neuroscience Research Center of Lyon studied brain temperature in pigeons and bearded dragon lizards, which have two sleep states similar in some respects to mammals. While they found brain cooling during NREM sleep and small, but consistent brain warming related to REM sleep in pigeons, brain temperature did not change when bearded dragons switched to the sleep state with wake-like brain activity. Therefore, the researchers challenge the hypothesis that the universal function of sleep states characterized by wake-like brain activity is to warm the brain in preparation for wakefulness.
Copyright Image: Damond Kyllo
In birds and other species alike, pairs can face considerable difficulties with reproduction. Scientists of the Department of Behavioural Ecology and Evolutionary Genetics have now shown in an extensive analysis of 23,000 zebra finch eggs that infertility is mainly due to males, while high embryo mortality is more a problem of the females. Inbreeding, age of the parents and conditions experienced when growing up had surprisingly little influence on reproductive failures.
Copyright drawing: Yifan Pei
Researchers led by Manfred Gahr in Seewiesen have investigated the relationship of bird families. For the first time, they have been able to clarify the relationship of all families of non-passerine birds and almost all families of passerine birds. The new family tree is based on gene sections that do not code for proteins, but contain sequences that are specific to the families and their genera.
Copyright image: André Labetaa
Scientists of the department Behavioural Neurobiology have investigated the neural basis of the vocal interaction of zebra finch pairs that form lifelong partnerships. The researchers found that in males, the neurons of a specific brain area (the so-called HVC) were activated as soon as they heard the calls of their female partner, even if the later was not present. What is particularly exciting, however, is the finding that in the presence of females, i.e. in a normal social context, the HVC neurons are only activated by the calls of the females, if the males were able to anticipate them in advance. In this case, in a way that has not yet been clarified, a neuronal excitation and then a reaction of the mentioned male HVC neurons occurs before the call of the female. The male was thus able to respond more quickly to the female calls, which probably plays an important role for pair bonding and thus breeding success.
Hummingbirds are the smallest birds with the fastest heart rate and the largest flight muscles, just to name a few record-breaking characteristics. Some species communicate through complex sounds that are learned early in life, comparable to the process of language acquisition of humans. How exactly these complex sounds are produced has now been discovered by scientists from Seewiesen in collaboration with the Zoologische Staatsammlung München using three-dimensional computer tomography scans, with which they were able to create a high-resolution digital map of the morphology of the vocal organ (syrinx) of the black hummingbird. Due to its location on the outside of the thoracic cavity and the course of the muscles, the syrinx is not affected during the extensive flight movements. The small organ also contains ossicles that are potentially related to the production of high-pitched sounds. Altogether, the hummingbird syrinx enables precise control and production of the sounds.
Male pectoral sandpipers typically visit several potential breeding sites during the short arctic summer. The decision about where to go next seems to be made opportunistically: they often leave in the direction the wind takes them. Researchers of the Max Planck Institute for Ornithology in Seewiesen tracked the flight path of 80 males with the help of small satellite transmitters and found that breeding areas in the Russian Arctic are more likely to be visited under tailwind conditions. In an environment where the summer is short and mating opportunities are unpredictable, individuals may save time and energy by using wind support.
Noise pollution is one of the leading environmental health risks in humans. In zebra finches, noise affects their health and the growth of their offspring: Researchers at the Max Planck Institute for Ornithology in Seewiesen found that traffic noise suppresses normal glucocorticoid profiles in the blood, probably to prevent negative effects of chronically elevated levels on the organism. In addition, the young chicks of noise-exposed parents were smaller than chicks from quiet nests.
The focus of the new Max Planck Institute of Animal Behaviour in Radolfzell and Konstanz will be the investigation of Collective Behaviour. Besides of the existing departments of Martin Wikelski and Iain Couzin, another research department will be established. Margaret Crofoot from the University of California in Davis will investigate the formation of complex societies using the group behaviour of monkeys as an example. She is particularly interested in how the collective behaviour of a group emerges from the contacts and relationships between individuals.
(Image: Axel Griesch)