BL UECAP—BOA T-BILL 45 



its place further to the south and westward ; and the third, of a 

 lighter hue and with no chestnut, being the north-western form. 

 The genus Sialia is one of those that are midway between the re- 

 jDuted Families Sykiidx (Warbler) and Turdidai (Thrush), and with 

 Monticola and some others shew how hard it is to maintain any 

 valid distinction between them. The Bluebirds of North America 

 breed in holes of trees, and seem all to lay pale blue spotless eggs. 

 In Western India, Ceylon, and Burma, the name Bluebird is equally 

 well bestowed on the Irena -puella of modern ornithologists, which 

 is commonly referred to the chaotic groups Timeliidx or Crateropo- 

 dida} (Gates, Fauna of British India, Birds, i. pp. 239, 240), and has 

 several representatives in the Indian Eegion (Jerdon, B. India, ii. 

 p. 106) ; but the precise place of the genus must be regarded as 

 uncertain. According to Mr. Layard (B. S. Afr. p. 365), in the 

 seas of the Cape of Good Hope, the name is applied to a wholly 

 different kind of bird, Diomedea fuliginosa (Albatros). 



BLUECAP, a common name of the Blue Titmouse Pairus 

 cseruleus. 



BLUETHROAT, the English name by which the beautiful Mota- 

 cilla suecica of Linnaeus is now generally known. By some systematists 

 it has been referred to the genus ButiciUa (Redstart) or to Erithacus 

 (Redbreast), and by others regarded as the type of a distinct genus 

 Ctjanecula — the last view being perhaps justifiable. There are two, 

 if not three, forms of Bluethroat in which the male is cjuite distin- 

 guishable :—(l) the true C. suecica, with a bright bay spot in the 

 middle of its clear blue throat, breeding in Scandinavia, Northern 

 Russia, and Siberia, and wintering in^byssinia^ and India, though 

 rarely appearing in the intermediate countries, to the wonder of all 

 who have studied the mystery of the migration of birds ; next there 

 is (2) C. leucocyanea, with a white instead of a red gular spot, a 

 more western form, ranging from Barl^ary to Germany and Holland ; 

 and lastly (3) C. wolji, thought by some authorities (and not Avithout 

 reason) to be but an accidental variety of the preceding (2), with 

 its throat wholly blue, — a form of comparatively rare occuiTence. 

 The first of these is a not unfrequent, though very irregular visitant 

 to England, while the second has appeared there but seldom, and 

 the third never, so far as is known. The affinity of the Bluethroat 

 to the Redstart is undeniable ; but it is not much further removed 

 from the Nightingale, and forms a member of that group which 

 connects the so-called Families Sylviidds (Warbler) and Turdidx 

 (Thrush). 



BOAT-BILL, the Cancroma cochlearia of most ornithologists, a 

 native of Tropical America, and the only species of its genus. It 

 seems to be merely a Night-HERON (Nycticorax) with an exaggerated 

 bill, so much v/idened as to suggest its English name, and its habits, 



F. 



