It has no definite color.

The fourth trait of this solitary bird is that it has no definite color. It desires to do nothing definite other that the will of God. The Holy Spirit gives the soul what is lacking in it by strengthening it to love as he loves. The soul's will is not destroyed it is united firmly with God's will and with his love "so that there is only one will and love, which is God's "(Spiritual Canticle 38:3). The Blessed Virgin Mary was raised from the beginning to this high state of contemplation. "She never had the form of any creature impressed in her soul, nor was she moved by any, for she was always moved by the Holy Spirit." (Ascent 3:2,10)