Nestling odour modulates behavioural response in male, but not in female zebra finches.

Studies investigating parent offspring recognition in birds led to the conclusion that offspring recognition is absent at the early nestling stage. Especially male songbirds were often assumed to be unable to discriminate between own and foreign offspring. However, olfactory offspring recognition in birds has not been taken into account as yet, probably because particularly songbirds have for a long time been assumed anosmic.

Different Reactions of Zebra Finches and Bengalese Finches to a Three-Component Mixture of Anesthetics.

Kawai et al. (2011) recently introduced a mixture of three anesthetic agents (here called MMB) that has an effect similar to ketamine/xylazine in mice, which might allow more effective reaction to changes in the animal condition, as an antagonist is available, and which can be used without license for handling narcotic drugs. Using Kawai's study as a baseline, we tested whether this anesthesia and its antagonist can also be used in avian studies.

Social odour activates the hippocampal formation in zebra finches (Taeniopygia guttata).

Experiments from our research group have demonstrated that the olfactory sense of birds, which has been considered as unimportant for a long time, plays a prominent role as communication channel in social behaviour. Odour cues are used e.g.

Chick Development and Asynchroneous Hatching in the Zebra Finch (Taeniopygia guttata castanotis).

The mode of hatching in birds has important impacts on both parents and chicks, including the costs and risks of breeding for parents, and sibling competition in a clutch. Birds with multiple eggs in a single clutch often begin incubating when most eggs are laid, thereby reducing time of incubation, nursing burden, and sibling competition. In some songbirds and some other species, however, incubation starts immediately after the first egg is laid, and the chicks thus hatch asynchronously.

Multiple Visual Field Representations in the Visual Wulst of a Laterally Eyed Bird, the Zebra Finch (Taeniopygia guttata).

The visual wulst is the telencephalic target of the avian thalamofugal visual system. It contains several retinotopically organised representations of the contralateral visual field. We used optical imaging of intrinsic signals, electrophysiological recordings, and retrograde tracing with two fluorescent tracers to evaluate properties of these representations in the zebra finch, a songbird with laterally placed eyes.

Features of the retinotopic representation in the visual wulst of a laterally eyed bird, the zebra finch (Taeniopygia guttata).

The visual wulst of the zebra finch comprises at least two retinotopic maps of the contralateral eye. As yet, it is not known how much of the visual field is represented in the wulst neuronal maps, how the organization of the maps is related to the retinal architecture, and how information from the ipsilateral eye is involved in the activation of the wulst. Here, we have used autofluorescent flavoprotein imaging and classical anatomical methods to investigate such characteristics of the most posterior map of the multiple retinotopic representations.

Effects of social conditions during adolescence on courtship and aggressive behavior are not abolished by adult social experience.

Social experience during adolescence has long-lasting consequences for adult social behavior in many species. In zebra finches, individuals reared in pairs during adolescence start to court females faster, sing more courtship motifs to females and are more aggressive compared with group-reared males. We investigated whether such differences are stable during adulthood or can be abolished by novel social experience after adolescence by giving all birds extensive experience with group life during adulthood.

Behavioral and neural trade-offs between song complexity and stress reaction in a wild and a domesticated finch strain.

The Bengalese finch is the domesticated strain of the wild white-rumped munia. Bengalese finches have been domesticated and reproductively isolated for over 250 years from the wild strain. During this period, the courtship songs of the domesticated birds became phonologically and syntactically complex.

Flavoprotein autofluorescence imaging of visual system activity in zebra finches and mice.

Large-scale brain activity patterns can be visualized by optical imaging of intrinsic signals (OIS) based on activity-dependent changes in the blood oxygenation level. Another method, flavoprotein autofluorescence imaging (AFI), exploits the mitochondrial flavoprotein autofluorescence, which is enhanced during neuronal activity. In birds, topographic mapping of visual space has been shown in the visual wulst, the avian homologue of the mammalian visual cortex by using OIS.

Encoding of naturalistic optic flow by motion sensitive neurons of nucleus rotundus in the zebra finch (Taeniopygia guttata).

The retinal image changes that occur during locomotion, the optic flow, carry information about self-motion and the three-dimensional structure of the environment. Especially fast moving animals with only little binocular vision depend on these depth cues for maneuvering. They actively control their gaze to facilitate perception of depth based on cues in the optic flow.

Very early development of nucleus taeniae of the amygdala.

The avian nucleus taeniae of the amygdala (TnA) corresponds to part of the mammalian medial amygdala. Like its mammalian counterpart, it has been shown to be involved in the control of social function. According to behavioral observations, such control is already necessary early in the ontogenetic development of a bird.

Activation changes in zebra finch (Taeniopygia guttata) brain areas evoked by alterations of the earth magnetic field.

Many animals are able to perceive the earth magnetic field and to use it for orientation and navigation within the environment. The mechanisms underlying the perception and processing of magnetic field information within the brain have been thoroughly studied, especially in birds, but are still obscure. Three hypotheses are currently discussed, dealing with ferromagnetic particles in the beak of birds, with the same sort of particles within the lagena organs, or describing magnetically influenced radical-pair processes within retinal photopigments.

Spatial memory and the avian hippocampus: research in zebra finches.

The aim of the present review is to show that spatial learning and memory is not a specialty of just a few avian species, and to describe the role of the avian hippocampus in spatial learning, memory and orientation. Based on our own research in zebra finches, we try to give an (not complete and probably biased) overview of this topic, and we also discuss the question of functional equivalence of hippocampus in birds and in mammals in that we question how far theories developed for mammalian hippocampus can also be applied to the avian hippocampal formation.

Avian ultraviolet/violet cones as magnetoreceptors: The problem of separating visual and magnetic information.

In a recent paper, we described the localization of cryptochrome 1a in the retina of domestic chickens, Gallus gallus, and European robins, Erithacus rubecula: Cryptochrome 1a was found exclusively along the membranes of the disks in the outer segments of the ultraviolet/violet single cones. Cryptochrome has been suggested to act as receptor molecule for the avian magnetic compass, which would mean that the UV/V cones have a double function: they mediate vision in the short-wavelength range and, at the same time, magnetic directional information. This has important implications and raises a number of questions, in particular, how the two types of input are separated.

Brain activation pattern depends on the strategy chosen by zebra finches to solve an orientation task.

Zebra finches (Taeniopygia guttata) were trained to find food in one of four feeders on the floor of an aviary. This feeder was always in the same place during training and was additionally marked by a distinct pattern. In the test trial the distinctly patterned feeder was interchanged with one of the other feeders, so that the birds had to decide to use either the pattern or the original location for finding food.

Spatial orientation in Japanese quails (Coturnix coturnix japonica).

Finding a given location can be based on a variety of strategies, for example on the estimation of spatial relations between landmarks, called spatial orientation. In galliform birds, spatial orientation has been demonstrated convincingly in very young domestic chicks. We wanted to know whether adult Japanese quails (Coturnix coturnix japonica) without food deprivation are also able to use spatial orientation.

Avian ultraviolet/violet cones identified as probable magnetoreceptors.

Background: The Radical-Pair-Model postulates that the reception of magnetic compass directions in birds is based on spin-chemical reactions in specialized photopigments in the eye, with cryptochromes discussed as candidate molecules. But so far, the exact subcellular characterization of these molecules in the retina remained unknown.

Methodology/principal Findings: We here describe the localization of cryptochrome 1a (Cry1a) in the retina of European robins, Erithacus rubecula, and domestic chickens, Gallus gallus, two species that have been shown to use the magnetic field for compass orientation.

Visual Wulst analyses "where" and entopallium analyses "what" in the zebra finch visual system.

Quite a lot of studies have tried to elucidate the differences in function of the two telencephalic targets of the avian visual system. We have tried to find out how the two systems are involved in orientation towards a food tray which is either marked by a special pattern or has to be identified by its relation to spatial cues. In this report, we compared in the zebra finch the effects of Wulst lesions on pattern discrimination with Wulst lesion effects on spatial discrimination, and we examined the effect of entopallium lesions on spatial discrimination.

Optical imaging of retinotopic maps in a small songbird, the zebra finch.

Background: The primary visual cortex of mammals is characterised by a retinotopic representation of the visual field. It has therefore been speculated that the visual wulst, the avian homologue of the visual cortex, also contains such a retinotopic map. We examined this for the first time by optical imaging of intrinsic signals in zebra finches, a small songbird with laterally placed eyes.

Amygdala and socio-sexual behavior in male zebra finches.

Neuroanatomical studies including pathway tracing and cytochemical characterizations have suggested that the avian nucleus taeniae of the amygdala (TnA) might be homologous to a part of the mammalian medial amygdala. Recent behavioral observations in TnA-lesioned birds also reported deficits in the control of motivational aspects of behavior, advancing the concept of homology of the structure in the two classes of animals. To further examine the functional role of TnA, we used a highly social, monogamous song bird species, the zebra finch, for our experiments.

Hippocampal activation of immediate early genes Zenk and c-Fos in zebra finches (Taeniopygia guttata) during learning and recall of a spatial memory task.

Zebra finches (Taeniopygia guttata) are able to learn the position of food by orienting on spatial cues in a 'dry water maze'. In the course of spatial learning, the hippocampus shows high expression of the immediate early genes (IEGs) Zenk and c-Fos, indicating high activation of this area during learning. In contrast, the IEG activity is nearly absent if the birds do not have to rely on spatial cues.

Oscillating magnetic field disrupts magnetic orientation in Zebra finches, Taeniopygia guttata.

Background: Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved.

Eye movements of laterally eyed birds are not independent.

Most birds have laterally placed eyes with two largely separated visual fields. According to studies in pigeons laterally eyed birds move their eyes independently in most situations, eye coordination just occurred during converging saccades towards frontal stimuli. Here we demonstrate for the first time that laterally eyed zebra finches show coordinated eye movements, regarding direction and amplitude.

Gaze strategy in the free flying zebra finch (Taeniopygia guttata).

Fast moving animals depend on cues derived from the optic flow on their retina. Optic flow from translational locomotion includes information about the three-dimensional composition of the environment, while optic flow experienced during a rotational self motion does not. Thus, a saccadic gaze strategy that segregates rotations from translational movements during locomotion will facilitate extraction of spatial information from the visual input.

The optokinetic response in wild type and white zebra finches.

Optic flow is a main source of information about self movement and the three-dimensional composition of the environment during locomotion. It is processed by the accessory optic system in all vertebrates. The optokinetic response is elicited by rotational optic flow, e.