فَإِنْ مَاتَتْ فِيهَا فَأْرَةٌ أَوْ عُصْفُورَةٌ أَوْ صَعْوَةٌ أَوْ سُودَانِيَّةٌ أَوْ سَامُّ أَبْرَصَ، نُزِحَ مِنْهَا مِنْ بَيْنِ عِشْرِينَ دَلْوًا إِلَى ثَلَاثِينَ بِحَسَبِ كِبَرِ الدَّلْوِ وَصِغَرِهَا
Translation: If a mouse, sparrow, sa‘wah, sudaniyyah or sam abrās dies in the well, draw between 20 and 30 buckets, taking the bucket’s size into account.
The terms list examples of smaller animals and birds. This bracket applies where the body has neither swollen nor decomposed; the later rule for swelling or disintegration supersedes it.