saltcat

from The Century Dictionary.

• noun A lump of salt made at a salt-works (see cat, n., 15); also, a mixture of gravel, loam, rubbish of old walls, cuminseed, salt, and stale urine, given as a digestive to pigeons.

from the GNU version of the Collaborative International Dictionary of English.

• noun A mixture of salt, coarse meal, lime, etc., attractive to pigeons.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A mixture of salt, coarse meal, lime, etc., attractive to pigeons.