Migratory songbirds use the geomagnetic field, stars, Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary calibrate all of these compass systems a common reference. We show that Savannah sparrows cues from region sky near horizon recalibrate magnetic at both sunrise sunset. suggest skylight polarization are used derive an absolute (i.e., geographic) directional system provides primary calibration reference for compasses songbirds.

SUMMARY Magnetic compass orientation in birds has been shown to be light dependent. Results from behavioural studies indicate that magnetoreception capabilities are disrupted under of peak wavelengths longer than 565 nm, and shifts have observed at higher intensities(43-44×1015 quanta s-1 m-2). To investigate further the function avian magnetic with respect wavelength intensity light, we carried out cage experiments juvenile European robins, caught during their first autumn migration,exposed...

Magnetic compass orientation by amphibians, and some insects, is mediated a light-dependent magnetoreception mechanism. Cryptochrome photopigments, best known for their role in circadian rhythms, are proposed to mediate such responses. In this paper, we explore properties of magnetic sensing at three levels: (i) behavioural (wavelength-dependent effects light on orientation), (ii) physiological (photoreceptors/photopigment systems with suggesting magnetoreception), (iii) molecular...

The light-dependent magnetic compass of birds provides orientation information about the spatial alignment geomagnetic field. It is proposed to be located in avian retina, and mediated by a light-induced, biochemical radical-pair mechanism involving cryptochromes as putative receptor molecules. At same time, are known for their role negative feedback loop circadian clock. We measured gene expression Cry1, Cry2 Cry4 muscle brain zebra finches over day assess whether they showed any...

Birds have remained the dominant model for studying mechanisms of animal navigation decades, with much what has been discovered coming from laboratory studies or systems. The miniaturisation tracking technology in recent years now promises opportunities during migration itself (migratory navigation) on an unprecedented scale. Even if are principally being designed other purposes, we argue that attention to salient environmental variables design analysis a study may enable host navigational...

Birds have a light-dependent magnetic compass that provides information about the spatial alignment of geomagnetic field. It is proposed to be located in avian retina and mediated by light-induced, radical-pair mechanism involving cryptochromes as sensory receptor molecules. To investigate how behavioural responses birds under different light spectra match with primary magnetoreceptor, we examined spectral properties zebra finches. We trained relocate food reward orientation task using cues....

The interaction and hierarchy of celestial magnetic compass cues used by migratory songbirds for orientation has long been the topic an intense debate. We have previously shown that Savannah sparrows, Passerculus sandwichensis, use polarized light near horizon at sunrise sunset to recalibrate their compass. Birds exposed a +/-90 deg. shifted artificial polarization pattern or recalibrated compass, but only when given full access cues, including horizon. In current study, we carried out cue...

Fat reserves influence the orientation of migrating songbirds at ecological barriers, such as expansive water crossings. Upon encountering a body water, fat migrants usually cross barrier exhibiting ‘forward’ migration in seasonally appropriate direction. In contrast, lean birds often exhibit temporary ‘reverse’ away from possibly to lead them suitable habitats for refueling. Most examples reverse are restricted autumn and, North America, largely limited transcontinental prior crossing Gulf...

Significance Birds have a light-dependent magnetic compass that is suggested to be mediated by light-induced, biochemical reactions in specialized magnetoreceptor molecules the avian retina. Natural skylight reaching these receptors always directional and some degree polarized, which has largely been neglected biophysical models behavioral experiments on sense. Training zebra finches spatial orientation assay, we show overhead polarized light modulates radical pair-based orientation. The...

Magnetoreception has been demonstrated in all five vertebrate classes. In rodents, nest building experiments have shown the use of magnetic cues by two families molerats, Siberian hamsters and C57BL/6 mice. However, assays widely used to study rodent spatial cognition (e.g. water maze, radial arm maze) failed provide evidence for cues. Here we show that mice can learn direction a submerged platform 4-armed (plus) maze. Naïve were given brief training trials. each trial, mouse was confined...

Stopovers play a crucial role for the success of migrating animals and are key to optimal migration theory. Variation in refuelling rates, stopover duration departure decisions among individuals has been related several external factors. The physiological mechanisms shaping ecology are, however, less well understood. Here, we explore how immune function blood parasite infections relate aspects behaviour autumn short- long-distance songbirds. We sampled six species used an automated...

The Earth's magnetic field and celestial cues provide animals with compass information during migration. Inherited courses are selected based on the angle of inclination, making it difficult to orient in near vertical fields found at high geomagnetic latitudes. Orientation cage experiments were performed different sites Arctic Canada adult young white–crowned sparrows (Zonotrichia leucophrys gambelii) order investigate birds' ability use for orientation naturally very steep close North Pole....

Abstract Animal movement acts at multiple scales: it can shape the destiny of individuals and populations, govern community ecosystem structure, influence evolutionary processes patterns biodiversity. Recent technological advances, such as revolutionary developments in tracking technology remote sensing, provide fresh insights possibility to collect detailed data on where how animals travel through space, they react and/or interact with their environment conspecifics well predators prey....