How very much like Thoreau this sounds! May of 1838 would have been in the first year of their friendship; In the Harvard UP edition - JMN 5 - "Bird-while" is the heading; but it appears without the hyphen in the text below "Birdwhile" p.499.

I wish I had access to the OED. Is it a neologism? On May 4, 1838 he writes: "The French seem to have somewhat negrofine in their taste" p.488

No trace of "negrofine" in a google search - but no access to OED! - Again a neologism or would I find it in OED?

A google search of birdwhile brought me here - a happy find!

– RegretLeft 2020-05-24 15:44 UTC

TY for comments, RegretLeft!

[1] quotes Emerson's diary about mushrooms and books:

19 September 1838.
‘I found in the wood this afternoon the drollest mushroom, tall, stately, pretending, uprearing its vast dome as if to say, “Well I am some thing! Burst, ye beholders! thou luck-beholder! with wonder.” Its dome was a deep yellow ground with fantastic, starlike ornaments richly overwrought; so shabby genteel, so negrofine, the St Peter’s of the beetles and pismires. Such ostentation in petto I never did see. I touched the white column with my stick, it nodded like old Troy, and so eagerly recovered the perpendicular as seemed to plead piteously with me not to burst the fabric of its pride. Shall I confess it? I could almost hear my little Waldo at home begging me, as when I have menaced his little block-house, and the little puff-ball seemed to say, “Don’t, Papa, pull it down!” So, after due admiration of this blister, this cupola of midges, I left the little scaramouch alone in its glory. Good-bye, Vanity, good bye, Nothing! Certainly there is comedy in the Divine Mind when these little vegetable self-conceits front the day as well as Newton or Goethe, with such impressive emptiness.

The greater is the man, the less are books to him. Day by day he lessens the distance between him and his authors, and soon finds very few to whom he can pay so high a compliment as to read them.’

– z 2020-05-25 10:52 UTC</div>