Hijaab of the Ansaari women
Question

                I am looking for the hadith that gives reference to the Ansar women appearing as crows after the verse 33:59 was revealed. It was my understanding that this was considered as proof that black as a color for hijaab was Sunnah, and therefore mustahab. Could you tell me where I could find this hadith, and       include its volume and number please?
Praise be to Allah.The hadeeth to which you refer was narrated by Abu Dawood, 
  may Allaah have mercy on him, in al-Sunan, from Umm Salamah who said: 
  “When the aayah ‘… to draw their cloaks (veils) all over their 
  bodies…’ [al-Ahzaab 33:59 – interpretation of the meaning] 
  was revealed, the women of the Ansaar came out looking as if there were crows 
  on their heads, because of their clothing.” (Sunan Abi Dawood, Kitaab 
  al-Libaas, Baab fi qawlihi ta’aala: yubneena ‘alayhinna jalaabeebihinna).
The author of ‘Awn al-Ma’bood fi Sharh Sunan Abi 
  Dawood said, commenting on this phrase: “Their veils were likened to 
  crows because of their black colour.”
However, it is not a condition of hijaab that the clothes should 
  be black, but it may be better because it is more concealing. For the conditions 
  of Muslim woman’s hijaab, please refer to question #214.