23 



NOTE ON LIFE AREAS. 



With regard to the distribution of birds, ornithologists have hitherto accepted as 

 approximately correct the faunal areas as defined by Prof. J. A. Allen, of New York. 

 By him the breeding areas of certain birds were considered to fall within the 

 limits of one or more of these faunse. For instance the Slate-colored Junco {Junco 

 hi/emalis) was held, during the period of reproduction, to be limited in its southward dis- 

 persion by the Canadian fauna ; the Wood Thrush (Turdus mustelinus) by the Allegha- 

 nian, and the Cerulean Warbler (Dendroisca ccerulea) by the Carolinian. 



The mean summer temperature being considered the most important factor in 

 determining these divisions, latitude bad less to do with the question than altitude. For 

 instance, mountain tops in low latitudes were correctly held to be isolated portions of 

 the Arctic fauna. But Middlesex is uniform in its physical features, and yet representa- 

 tives of the three faunae given above have been found breeding in the county under 

 almost identical climatic conditions. Deep, cool swamps occur, which may account in 

 part for the presence of the more northern species, but on the whole there is such an 

 abnormal admixture of birds usually found in summer so far apart as to throw doubts 

 on the feasibility of maintaining such divisions. It is probable that the researches of Prof. 

 Merriam, Ornithologist for the Department of Agriculture at Washington, who has lately 

 given much attention to the problem of distribution, will prove that there are but two 

 life provinces in North America, viz : — The Boreal (Northern), and the Sonoran 

 (Southern) according as the forms of life inhabiting each have reached this continent from 

 the north or south. When the limits of these two great divisions are mapped out it will 

 likely be found that Middlesex occupies a neutral position, being on the whole Sonoran 

 rather than Boreal, but with a strong tinge of the latter. 



LIST OF BIRDS KNOWN TO BREED IN MIDDLESEX COUNTY, ONTARIO. 



BY THE LONDON ORNITHOLOGICAL SECTION OF THE ENTOMOLOGICAL SOCIETY. 



Those birds which are decidedly and directly beneficial on account of their feeding 

 habits are marked (a). Those which are neutral or nearly so are marked (6). Those 

 which are open to doubt as being possibly injurious are marked (c). 



(6) Aix SPONSA — Wood Duck. — Residents around the pond at Dorchester say it bred 

 there up to about five years ago. 



{h) BoTANRUS LENTIGINOSUS — Bittern — A nest of unfledged young found on the flats 

 at Arva in 1889, by W. A. Balkwill. 



(6) Ardea herodias — Great Blue Heron — A few heronries containing sometimes as 

 many as several hundred nests are known in the county, though they are becoming 

 gradually deserted. Occasionally single nests are found in high deciduous woods. 



(6) Ardea virescens — Green Heron — One nest found within two miles of the city in 

 1888 by W. A. Balkwill. Pairs are believed to breed in other parts of the county, having 

 been seen regularly in summer. 



(b) Philohela minor — American Woodcock — Not very common. 

 (b) AcTiTis MACULARius — Spotted Sandpiper — Breeds commonly in fields and waste 

 places near water. 



(a) tEgialitis vocifera — Kildeer Plover — Not very common, perhaps one pair to a 

 square mile. 



{h) CoLiNus virginianus — Bob-white — Abundant in the west and south, but quite 

 rare in the north-east of the county. 



