8 ADVERTISEMENT. 



our three hundred and twenty species described in one 

 volume of the size prescribed for the present series of 

 Manuals, the characters would be too brief to be of much 

 use. I have, therefore, devoted a volume to the Terres- 

 trial and another to the Aquatic species, prefixing to the 

 first a short Introduction to the Study of Ornithology, 

 including all the particulars requisite to enable one not 

 previously acquainted with the subject to compare the 

 objects with their descriptive characters. Although, in 

 a strictly scientific point of view, the division of birds into 

 those of the land and water is not commendable, it is con- 

 venient, and in some degree natural and familiar. 



The Classification of Birds is a subject of much dis- 

 pute. In fact, no two authors follow precisely the same 

 plan, or use the same nomenclature. In this state of un- 

 certainty, I have had recourse to nature, and endeavoured 

 to elicit a method which may be at least intelligible. In 

 some instances I have altered the names, conceiving them 

 to be erroneous, or inconsistent ; but in every case, the 

 popular, and some of the scientific, appellations are given. 

 The generic characters, as well as those of the orders, 

 include some particulars, especially with reference to the 

 digestive organs, not given in other works, but easily in- 

 telligible, and of great importance as indicative of the 

 mode of life of the species. Those who are desirous of 

 obtaining more extended information on this subject, I 

 refer to the only work known to me in which they will 

 find it, my History of British Birds, of which three vo- 

 lumes, including all the species referred to in this Manual, 

 have recently been published. 



EDINBURGH, 2oth October 1840. 



