I have never seen a male of the Cape May warbler with the upper part of the head pure black. Have you compared the Regulus with the description of Regulus Cuvieri? Could you not send me your bird to look at? Being on the eve of publishing the Quadrupeds of our Country, I have thought that you might have it in your power to procure several of the smaller species for me, and thereby assist me considerably. Please write to me again soon, as I must resume my travels in 8 or 10 days. Have you seen a copy of the small edition of The Birds of America which I am now publishing? Believe me, dear sir,
With good wishes, your obt. sert.,
John J. Audubon
Thus began a correspondence between the youth of fifteen and the veteran of fifty-five, which led to an intimate friendship that lasted during Audubon's active career, and was an undoubted stimulus to young Baird, whose talents, enthusiasm and industry were quickly appreciated by the older naturalist. Baird answered Audubon's letter on June 20, and proffered his services in collecting mammals, saying that while they were more difficult to find than birds, he hoped "by increased exertion to make up the difference"; he also added: "I have seen some numbers of your work now publishing, and admire them very much. I have no doubt that it will do more to spread a love of Natural history, than any work ever published. For my part I read the description of birds and the episodes in your Ornithological Biography with the same motive of pleasure as I used to read a favorite novel." In Audubon's immediate reply of the 22nd, he said:
It is impossible at present for me to give you any precise idea of the work on our quadrupeds which I have in contemplation to publish, any further than to say to you, that it is my intention, as well as that of my friend, the Revd John Bachman, of Charleston, S. C., assisted by several others of our best naturalists, to issue a work on the Mammalia of North America worthy of the naturalist's attention, both at home and abroad.—Through our joint efforts, and assisted as we hope and trust to be, by numerous friends and acquaintances in different portions of our Wide Union, we expect to collect, not only new species, but much of valuable matter connected with their geographical range, and particular habits. For instance, in your assistance in this department as well as in ornithology, you may be able to send us valuable intelligence respecting the Shrews, Mice, Rats, Squirrels, etc., found in your immediate vicinity &c.—and by saving and forwarding specimens to us, be able also, in all probability, to place into our hands, objects never before known to the World of Science. Whatever information we thus receive is sacredly published under the name of the friend from whom we receive the information, etc. I have sent you the Zoological report of Docr. De Kay. His Corvus cocolotle [cacolotl] is really our Raven. Supposed by some inexperienced European naturalists to be distinct from the Raven of Europe, which, however, is a gross error.[179]...
The thrush which you have described, and which you kindly offer to send me, may be new, but perhaps you are not acquainted with the Turdus Nanus of my work, to which it appears, if not the same, probably a new variety! Nous verrons....
Please to collect all the Shrews, Mice, (field or wood), rats, bats, Squirrels, etc., and put them in a jar in common Rum, not whiskey, brandy or alcohol. All of the latter spirits are sure to injure the subjects.
Audubon, who was now "killing two birds with one stone"—collecting subscribers for one work and mammals for another, had found a strong and willing helper in the young naturalist of Carlisle. On December 10 of the same year Baird wrote that he had discovered another Flycatcher, as well as a small Woodpecker, which was apparently new, and had shot a "Bay Lynx or Wild Cat a mile & a quarter from Carlisle; the cat ... was 2½ feet long & weighed 12½ pounds.... It was a source of great regret," said Baird, "that I was not able to meet you in Philadelphia when I was there during the latter part of September. I saw Mr. Chevalier[180] several times, and found him a very agreeable gentleman." Audubon replied to this letter on Christmas Day, as follows:
Audubon to Spencer Fullerton Baird
New York, December 25, 1840.
My dear sir,