A magnet attached to the forehead disrupts magnetic compass orientation in a migratory songbird

For studies on magnetic compass orientation and navigation performance in small bird species, controlled experiments with orientation cages inside an electromagnetic coil system are the most prominent methodological paradigm. These are, however, not applicable when studying larger bird species and/or orientation behaviour during free flight. For this, researchers have followed a very different approach. By attaching small magnets to birds, they intended to deprive them of access to meaningful magnetic information. Unfortunately, results from studies using this approach appear rather inconsistent. As these are based on experiments with birds under free flight conditions, which usually do not allow exclusion of other potential orientation cues, an assessment of the overall efficacy of this approach is difficult to conduct. Here, we directly test the efficacy of small magnets for temporarily disrupting magnetic compass orientation in small migratory songbirds using orientation cages under controlled experimental conditions. We found that birds which have access to the Earth's magnetic field as their sole orientation cue show a general orientation towards their seasonally appropriate migratory direction. When carrying magnets on their forehead under these conditions, the same birds become disoriented. However, under changed conditions that allow birds access to other (i.e. celestial) orientation cues, any disruptive effect of the magnets they carry appears obscured. Our results provide clear evidence for the efficacy of the magnet approach for temporarily disrupting magnetic compass orientation in birds, but also reveal its limitations for application in experiments under free flight conditions.

A Temporal Boosted YOLO-Based Model for Birds Detection around Wind Farms

Object detection for sky surveillance is a challenging problem due to having small objects in a large volume and a constantly changing background which requires high resolution frames. For example, detecting flying birds in wind farms to prevent their collision with the wind turbines. This paper proposes a YOLOv4-based ensemble model for bird detection in grayscale videos captured around wind turbines in wind farms. In order to tackle this problem, we introduce two datasets—(1) Klim and (2) Skagen—collected at two locations in Denmark. We use Klim training set to train three increasingly capable YOLOv4 based models. Model 1 uses YOLOv4 trained on the Klim dataset, Model 2 introduces tiling to improve small bird detection, and the last model uses tiling and temporal stacking and achieves the best mAP values on both Klim and Skagen datasets. We used this model to set up an ensemble detector, which further improves mAP values on both datasets. The three models achieve testing mAP values of 82%, 88%, and 90% on the Klim dataset. mAP values for Model 1 and Model 3 on the Skagen dataset are 60% and 92%. Improving object detection accuracy could mitigate birds’ mortality rate by choosing the locations for such establishment and the turbines location. It can also be used to improve the collision avoidance systems used in wind energy facilities.

Windcatcher

A short-tailed shearwater flies from the edge of the Southern Ocean to the rim of the Arctic Circle – and back – every year. This remarkable 30,000 kilometre journey is driven by seabird law. Instinct and community will guide her. A wingspan the size of a child’s outstretched arms will support her. But first, she must catch the wind … Based on birds that live on Griffiths Island, near Port Fairy, Victoria, Windcatcher is a tale of migration, conservation and survival that begins with one small bird called Hope. Written by award-winning children’s author Diane Jackson Hill and illustrated by Craig Smith, one of Australia’s most prolific and popular illustrators, Windcatcher explores the mysteries of seabird migration. For primary aged readers.

31° South: phenotypic flexibility in adaptive thermogenesis among conspecific populations of an arid-endemic bird - from organismal to cellular level

ABSTRACTIn north-temperate small passerines, overwinter survival is associated with a reversibly increased maximum cold-induced metabolism (Msum). This strategy may incur increased energy consumption. Therefore, species inhabiting ecosystems characterized by cold winters and low productivity (i.e., low available energy) may be precluded from displaying an increase in maximum metabolic rates. To examine whether Msumis a flexible phenotype in such challenging environments, and ultimately uncover its underpinning mechanisms, we studied an arid-endemic small bird (Karoo scrub-robin) whose range spans a primary productivity and minimum temperature gradient. We measured Msum, body condition, mass of thermogenic muscles and two indices of cellular aerobic capacity from populations living in three environmentally different regions. We found that Msumwas seasonally flexible, associated with aerobic capacity of limb muscles, but not increasing with lower temperatures, as predicted. Notwithstanding, the cold limit (temperature at which birds reached their maximum metabolic capacity) decreased in winter. These results indicate that birds from arid-zones may respond to cold conditions by altering thermosensation, rather than spending energy to produce heat in skeletal muscles.

On the diminutive morpheme -gama in Ikema, a Ryukyuan language

Ikema is defined as ‘definitely endangered’ by UNESCO (2009). The study examines an evaluative morpheme -gama used by old Ikema speakers aged 64 to 86 when speaking between Ikema speakers and when speaking Standard Japanese with outsiders. Descriptive grammar of Ikema (Hayashi 2010; Hayashi 2013 inter alia) has treated -gama as diminutive morpheme, representing smallness such as tui-gama ‘small bird’ or showing the affections to the base noun. The observations on naturally occurring data, however, revealed that the Ikema speakers barely used -gama by means of describing smallness: the most frequent use of -gama was found to be non-supplementary (Shetter 1959) and carries various socio-pragmatic functions. The related meanings/functions of -gama are presented in radial category (Lakoff 1987).