The study, published in the April issue of the American Naturalist, was conducted between June 2003 and June 2005 on the isle of Oléron, off the west coast of France, where Christian Bavoux and Guy Burneleau have been studying the local scops owl population since 1981.
The authors have analyzed several hundreds of hoots recorded from 17 territorial males and demonstrated that the pitch of the vocalization reflects the body weight of the male: the heavier the male, the lower the pitch of his hoots. In order to see whether this information is actually used by male owls during territorial interactions, the authors conducted a series of playback experiments (commonly used in studies of animal communication in order to assess the function of vocal signals), monitoring the reaction of subjects to the broadcast of vocalizations. To do this they modified the pitch of several hoots, creating stimuli that mimicked the hoots given by males from a range of body weights. They then played back these recordings to males with established territories, and observed and quantified their response (a combination of approaches and vocal responses). The results show that male owls respond more strongly to the high-pitched calls that simulate lighter individuals, confirming that territorial males attend to pitch information advertising body weight in the calls of their competitors. The authors also found that the territory owners give slightly lower pitched hoots in response to calls mimicking heavier males, probably indicating that they attempted to sound heavier when challenged by more threatening individuals.
"The fact that owls are essentially active during the night puts a strong emphasis on acoustic communication as a means of assessment, both during male competition and during mate choice," says Loïc Hardouin who recently completed a PhD on acoustic communication and territoriality in owls. "The next step is to see whether females use these quality cues when they choose their mating partner." "The vocal communication of owls has interesting similarities to that of terrestrial mammals where the information is typically encoded in acoustic components of the calls rather than in the diversity of the vocal repertoire as it is in songbirds," says Reby, who is an expert in the study of mammal vocal communication.
Patricia Morse | EurekAlert!
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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