Urbanization is increasing worldwide; most humans nowadays live in cities. Despite of the associated general decline in diversity due to habitat fragmentation, availability of resources or pollution, there are examples of species that successfully colonize urban habitats. Now, a group of researchers around Jakob Mueller and Bart Kempenaers performed a genome-wide comparision of urban against rural burrowing owls, a bird species that colonized South American cities just a few decades ago. Among other things, the researchers found in city birds selection signals in genes that act in synapses and neuron projections in the brain with potential control functions for cognitive and emotional behaviour and could thus play an important role in the adaptation to the urban environment.
(Image copyright: José L. Tella)
Starlings sleep five hours less per night during the summer. Compared to winter, the birds take more mid-day naps and live under higher sleep pressure. During full-moon nights, starlings sleep around two hours less than usual. In their study, researchers of the Universities of Groningen and Zurich together with research group leader Niels Rattenborg from Seewiesen show that sleep regulation in starling birds is highly flexible and sensitive to environmental factors.
Sjoerd J. van Hasselt, Maria Rusche, Alexei L. Vyssotski, Simon Verhulst, Niels C. Rattenborg, and Peter Meerlo: Sleep Time in the European Starling Is Strongly Affected by Night Length and Moon Phase. Current Biology, 19 March 2020
Winter associations predict social and extra-pair mating patterns in blue tits. Researchers of the Max Planck Institute for Ornithology and the MPI for Animal Behaviour show in their new study that blue tits that often foraged together during winter were more likely to end up as breeding pairs or as extra-pair partners, whereby bonds between future breeding partners seem to establish earlier in winter than those between future extra-pair partners.
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.
In birds, timing of arrival in a breeding area influences who ends up breeding and who does not. This aspect of behaviour, well-known in migratory birds, has now been studied for the first time in a non-migratory species, the blue tit. Carol Gilsenan, Mihai Valcu and Bart Kempenaers found that arrival time in the breeding area was an individual-specific and fitness-relevant trait for this resident bird species, as early-arriving individuals were more likely to breed in that year. The study suggests that it might be worthwhile to consider migration on different scales, not only as movements over thousands of kilometres to wintering grounds, but also more generally as movements between breeding and non-breeding sites.
Parrots are considered extraordinarily clever animals. Alex, the famous Harvard-based African grey parrot, communicated with a vocabulary of more than 500 human words, could answer questions and classify objects spontaneously. Scientists from the Max-Planck-Institute for Ornithology based at the research station outpost for parrot comparative cognition in the Loro Parque in Tenerife, Spain, have shown that parrots exhibit a high level of social intelligence and cooperativeness. They readily help others, even when there is no immediate opportunity for reciprocation. Moreover, they reciprocate received favours and do not appear jealous, if conspecifics obtain a better reward than themselves. This further supports that they have evolved a level of intelligence comparable to that of great apes, crows and dolphins.
Zebra finches can take turns when exchanging short calls with one another, much like humans do during conversations. Researchers from the Max Planck Institute for Ornithology have now shed light on the underlying neural dynamics in a songbird brain area called HVC, or the so called “song control centre”. The researchers identified neurons involved in initiating a call as well as another class of neurons that inhibits neighboring cells shortly before a bird calls. The importance of these cells for vocal turn-taking was further supported by the observation that specific disruptions to the signaling of either type of neuron resulted in distinct changes in call timing.
Everybody knows about the difficulty of focusing on a conversation during a loud party. How can active sensing animals like bats move in large groups and still be able to detect each other despite jamming? Thejasvi Beleyur and Holger Goerlitz show in their new modelling study in PNAS that a focal bat in the center of a group can still detect its closest neighbours in groups with 100 bats. Neighbor detection is improved for longer call intervals, shorter call durations, denser groups and more variable flight and sonar beam directions. Although the bats only detect their closest and frontal neighbours, this gives them sufficient information to prevent collisions, and to follow each other when emerging in dense swarms.
The timing of spring migration is vital for birds. Returning too late comes at a cost. In 1981, Ebo Gwinner, former director of the MPI for Ornithology demonstrated how an internal clock is responsible for the correct timing of flycatchers’ migration. Replicating this experiment more than twenty years later, Barbara Helm, student of Ebo and now Professor at the University of Groningen and guest researcher in Seewiesen has shown there is an evolutionary response of this clock to climate change, as migratory restlessness in spring is advanced by more than nine days.
Open link to the study with click on the image
Image with kind permission from Ralph Martin, Germany; www.visual-nature.de
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.
When a male or female white-browed sparrow-weaver begins its song, its partner joins in at a certain time. They duet with each other by singing in turn and precisely in tune. A team led by researchers from the Max Planck Institute for Ornithology in Seewiesen found that the nerve cell activity in the brain of the singing bird changes and synchronizes with its partner when the partner begins to sing. The brains of both animals then essentially function as one, which leads to the perfect duet.
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)