Scientists from the Avian Sleep Research Group (Niels Rattenborg), the Behavioral Neurobiology Department (Manfred Gahr) and the Evolutionary Physiology Group (Michaela Hau) explain current research projects in the MDR three-part series "The Secret of Birds" (Part 2 in the ARD Media Library, mostly in German language).
Humans can easily identify sweet-tasting foods – and with pleasure. However, many carnivorous animals lack this ability. Whether birds, descendants of meat-eating dinosaurs, can taste sweet was previously unclear. An international team of researchers from Japan, Germany, Hong Kong, the United States and Australia, led by Maude Baldwin, has now shown that songbirds, with more than 4,000 species, recognize sweets regardless of their primary diet. In the journal SCIENCE, the study highlights a specific event in the songbird ancestors that allowed their umami (savory) taste receptor to recognize sugar. This ability has been conserved in the songbird lineage, influencing the diet of nearly half of all birds living today.
Photo: Andy Gee, Macaulay Library #304552631
It is well known that women live longer on average than men. In the rest of the animal kingdom, we also observe gender-specific differences in life span. According to a theory, the reason for this could be sexual selection: The sex that competes for a mate is subject to higher mortality - in most cases the male. Researchers have now studied the life spans of barred buttonquails for the first time. This is one of the few bird species with "reversed" sex roles. While males take care of the brood, females engage in territory defense and mate attraction. Interestingly, in this case, the males outlive the females. Thus, the researchers provide direct evidence corroborating the influence of sexual selection on lifespan.
Traffic noise leads to inaccuracies and delays in the development of song learning in young birds. They also suffer from a suppressed immune system, which is an indicator of chronic stress. A new study by research group leader Henrik Brumm and colleagues shows that young zebra finches, just like children, are particularly vulnerable to the effects of noise because of its potential to interfere with learning at a critical developmental stage.
In snowy plovers, females have overcome traditional family stereotypes. They often abandon the family to begin a clutch with a new partner whereas the males continue to care for their young until they are independent. An international team led by scientists from the Max Planck Institute for Ornithology in Seewiesen, Germany, has now investigated the decision-making process that determines the duration of parental care by females. They found that offspring desertion often occurs either under poor environmental conditions, when chicks die despite being cared for by both parents, or when chicks have a good chance of survival even without the female.
Bavaria invests in the competitive development of the Martinsried Max Planck Campus into an outstanding international research hub. Our institute in Seewiesen will - subject to the approval of the Senate - merge with the Max Planck Institute for Neurobiology to form a joint new Max Planck Institute for Biological Intelligence and expand with additional departments in the coming years. Seewiesen is to be retained as an outstation for research in natural environments.
The Free State of Bavaria intends to fund the project with up to 500 million euros over the next ten years, after approval of the state parliament. Minister President Markus Söder and Max Planck President Martin Stratmann signed a corresponding Memorandum of Understanding on April 29, 2021 in the Max Planck House in Munich.
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:
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.
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
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