Über die Heimfindeleistungen von Brieftauben nach Haltung in verschiedenartig abgeschirmten Volieren

Summary

A series of experiments initiated by the lateG. Kramer was continued and evaluated as a whole.

1,111 young homing pigeons were placed in aviaries before they could fly. At least three months later they were released individually at distances of 90–100 miles from the loft. 374 birds were recovered; the rest were lost (Table 1).

The pigeons raised in relatively free standing „open avaries (O)“ showed a clear homeward orientation (Abb. 11, 12).

The homing performances of the pigeons of the following types of aviaries were significantly worse than the performances of the birds of these open aviaries (Table 3), and there is no evidence for a connection between their places of recovery and the home loft:

• 1. “Full palisade (P)”. The aviary was surrounded by a wooden wall a little higher than the aviary itself (map of records see Abb. 15).

• 2. “Low crater aviary (KN)”. The aviary was placed in a depression of the ground, thus preventing the pigeons from seeing the horizon (Abb. 14).

• 3. “Palisade with northern gap (NL)”. The wooden palisade was opened to the north allowing a view of most parts of the northern semicircle (Abb. 16).

• 4. “Palisade with southern gap (SL)”. There was an analogous gap in the south (Abb. 18).

• 5. “Glass palisade (Gl)”. The upper part of the surrounding wall was made of glass. The visual conditions were the same as in the “open” aviaries (Abb. 20).

The performances of the pigeons of the following types of aviaries did not differ significantly from the performances of the birds of the „open“ aviaries, and there is a proven or a probable connection between their places of recovery and the home loft:

• 1. “Roofed palisade (Dh)”. The aviary was placed under a wooden roof. Only the lowest parts of the sky could be seen through a narrow slit. The pigeons could never see the sun since the slit was closed from early evening to late morning (Abb. 21). (If the birds were kept in a constant day length of 16 hours their performances corresponded to those of the “bad” aviary group: Abb. 22).

• 2. “High crater aviary (KH)”. The aviary in a depression of the ground was provided with a “second story” enabling the pigeons to have a similar view to the south as from the “palisade with southern gap” (Abb. 17).

• 3. “Palisade with five gaps (5 L)”. The pigeons could see in all directions, although not simultaneously from one point, but only successively from different perching places (Abb. 19).

The “palisade effect” can be demonstrated by several different performance criteria which show good agreement with eachother (Abb. 27). It suggests that the barriers between the aviary and the external world interrupt or change a substrate of information spreading in the horizontal plane which is important for homing ability. Its nature is unknown.