Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Birds are divided in the Mosaic law into two classes,
When offered in sacrifice, they were not divided as other victims were (Gen. 15:10). They are mentioned also as an article of food (Dt. 14:11). The art of snaring wild birds is referred to (Ps. 124:7; Pr. 1:17, 7:23; Jer. 5:27). Singing birds are mentioned in Ps. 104:12; Eccl. 12:4. Their timidity is alluded to (Hos. 11:11). The reference in Ps. 84:3 to the swallow and the sparrow may be only a comparison equivalent to, "What her house is to the sparrow, and her nest to the swallow, that thine altars are to my soul."