Jakob Kiepenheuer

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Fig. 1. Pooled vanishing bearings of five test releases from 65.2 km SSW; the different symbols at the periphery of the circles indicate the bearings of the five individual releases. The home direction 17 ~ is marked by a dashed line. The arrows indicate the mean vector the length of which is drawn proportional to the radius of the circle=l. (a) Controls:(More)
To test the present hypotheses concerning the functioning of the bird's magnetic compass, pigeons reared near the magnetic and geographic equator (Fortaleza, NE Brasil) were released 300 km NW of their home in the horizontal field at the magnetic equator. Pigeons released in the morning and in the afternoon were roughly homeward oriented whereas pigeons(More)
1. Pigeons reared in deflector cages show on release a very pronounced bias of their mean vanishing bearings in the predicted direction, confirming the results of Baldaccini et al. (1975a). The angle of deviation though is only about half the angle of actual wind deflection in the cages. The concentration of bearings about the mean direction is(More)
Supplementary to a previous investigation (Wallraff and Neumann 1989), further experiments were conducted with homing pigeons that were either familiar of unfamiliar with the release area, and that had or lacked olfactory access to environmental odours. All four possible pairwise combinations of these factors were tested. The previous results were(More)
Earlier experiments led to the conclusion that homing pigeons are able to deduce positional information from atmospheric odours they perceive at the site of release. Here we show that this ability is significantly reduced, if the inhaled air does not originate from the free airspace in an open landscape but from a close-to-the-ground level of a forest or a(More)
The aim of the experiment was to test the hypothesis that pigeons depend on route- and/or site-specific airborne parameters to establish their position relative to the loft. Pigeons were transported to the release site with free access to the environmental air. They were then enclosed in large airtight containers filled with air from the release site and(More)
between attacks is shown in Fig. 1 c. Before an attack, the duration of intervals is between 60 and 100 ms, with some longer intervals distributed among them. During the approach of the opponent, interval length diminishes rapidly (discharge rate accelerates). Within -28 intervals, the highest discharge rate is reached. The shortest interval, displayed(More)
2 dB were differentiated at sound intensities o f 70 and 80 dB (SPL) (Weber fractions between 0.11 and 0.32) without the influence of test tone frequency. A deterioration can be noticed in the marginal area of the auditory capacity (6 kHz). A linear dependence between capacity of intensity discrimination and sound intensity of the test tone could be shown:(More)
ther information acquired at or en route to the site. Air was collected in two large (750-1) plastic containers at four sites located 11-15 km symmetrically around the loft. The air containers were transported back to the loft. Five pigeons were placed inside each, through a lockdoor, for a period of 2 h. The olfactory mucosae of all pigeons still inside(More)
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