I like the drawing and the verse written by you. It is amazing how you pointed out the little feathers just by some pencil strokes. By the darker more intensive colours of the branches and the lighter background, the sparrow is really put into the focus. You have also centered it in the drawing and that highlights it still more.
Concerning the Tanka you have strictly kept the Tanka verse rhyme (5-7-5-7-7) concerning the syllables. And it refers to human nature as haiku is more refering to nature outdoors. You have stuck to this as well. I like the message you have concealed in your written work. The appearance does not matter nor the first impression but what is behind all that is the essence of a personality. In combination with the sparrow: It looks rather simple as a bird but can be so beautiful in playing and being around. Also when other birds might sing better, I like the tunes a sparrow sing. And those birds show their gratitude by singing the whole day in front of my window for having them fed all over the winter time