From A. G. Butler   8 May 1877

My dear Sir

Can you tell me if the House-Sparrow is the most stupid of all birds? I do not believe that this bird has either memory or reflection.¹

A pair of sparrows just three weeks ago fixed upon a sun-blind at the back of my house as a place in which to build their nest, (the blind does not quite close up at one end which permits them to enter)

Every morning this blind is pulled down, and regularly every morning the commencement of the nest comes down with it, but (although I have even buried the nest) as soon as the blind is pulled up, the two sparrows who have been watching from the house-top immediately fly down and recommence operations; they are now engaged in collecting rubbish for about the 22^nd. time.

Upon my word I don’t believe that birds reflect a bit more than bees and ants do (if so much).

If this sort of thing goes on I think I must write a note upon it for the Annals & Magazine of Nat. Hist!²

I thought this little fact might be useful to you some time or other.

Believe me to be | yours very sincerely | Arthur G. Butler

Charles Darwin Esq. F.R.S. | &c. &c. &c.