Feral pigeon populations: their gene pool and links with local domestic breeds.

Columba livia is a wild bird whose domestication has led to a large number of pigeon breeds. The occasional loss or straying of domestic birds determined the origin of feral pigeons, which are now widespread all around the world. In this study, we assumed that the main contribution to feral populations is provided by domestic breeds reared in the same areas.

The effect of clock-shift on the initial orientation of wild rock doves ( Columba l. livia).

Previous experiments on wild rock doves ( Columba l. livia Gmelin) released within their familiar area revealed an evident effect of fast-shifting, although shifted doves, but not controls, tended to orient homeward. Such an outcome suggested a possible influence of the release time per se on the directional choices of the tested doves.

A comparative morphometric analysis of the optic nerve in two cetacean species, the striped dolphin (Stenella coeruleoalba) and fin whale (Balaenoptera physalus).

A comparative study was made on one Mysticete (the fin whale, Balaenoptera physalus) and one Odontocete species (the striped dolphin, Stenella coeruleoalba) by measuring several morphological characteristics seen in cross sections of the optic nerve. We found that the two cetacean nerves share a number of specializations that distinguish them from the optic nerve of terrestrial mammals. Fiber density is approximately two-fold lower than in land mammals.

Occurrence of a pyrazine binding protein in the nasal mucosa of some vertebrates.

The presence of an olfactory protein, specific for 2-isobutyl-3-methoxypyrazine, identified in cow olfactory mucosa, has been investigated in several species of all classes of vertebrates. The methods involved measurement of specific binding with the radioactive ligand and some competitors, as well as SDS electrophoresis on the crude homogenate. The results show that such protein is present only in some families of mammals, with no clear relationship to systematic position or to natural diet.

Identification of a specific olfactory receptor for 2-isobutyl-3-methoxypyrazine.

2-Isobutyl-3-methoxypyrazine, a potent bell-pepper odorant, binds to cow olfactory mucosa homogenate. The receptor is saturable in the micromolar range and is competitively inhibited by other bell-pepper odourants, but not by other pyrazines of different odours. Other tissues do not bind 2-isobutyl-3-methoxypyrazine at a significant extent.