iv ADVERTISEMENT. 
Where this has been imperfectly given, such additional facts 
relative to their manner of breeding, etc., as the space ad- 
mitted, have been added; and where the bird was not known 
to Witson, a brief scientific description has been appended. 
I should be guilty of great injustice, were I to omit to add 
how much I have been assisted by the labors and writings of 
the illustrious Aupuson. With his free and generous consent, 
I have been permitted to draw from the materials which his 
industry and perseverance had prepared to my hands, and 
without which I could have done but little. Whatever merits, 
therefore, may appear in my. labors, will, I trust, be attributed 
to the source to which they are rightly due. It will also be 
seen that in the arrangement by genera and families, the 
present Synopsis owes a great deal to that of Mr. Aupuzon. 
It, however, differs in two material points. The latter has no 
division by orders. The omission is an important one, and it 
was deemed advisable to supply it. I have also judged it 
inexpedient to imitate the needless subdivisions into genera, 
which is the prevailing fault in modern ornithology. Without 
entering into a discussion of this controverted question, I have 
only to urge, in defence of my adhesion except in such instances 
as it appeared wrong to do so, to old genera — my conviction 
that the present mode of subdivision, instead of tending to . 
simplify science, as its advocates assert, but adds to the difficul- 
ties of the beginner, and serves to discourage his efforts to 
master the subject. 
Th fine, I would venture to submit this brief catalogue of the 
birds of North America, with the assurance, which justice 
compels me to make, that its merits, if it has any, are due to 
others; its faults—and I am aware of its deficiencies — are 
partly mine, and partly those of my narrow limits. 
T. WM. B. 
