XXxiV YORKSHIRE—VERTEBRATE FAUNA. 
A comparison of the three avifaunas—based upon a careful 
analysis in accordance with the faunistic definitions given on 
page xi—yields the following results :— 

North- 








umber- | York- AA 
land and|_ shire Norfolk 
Durham 
RESIDENTS - - - -| 83 88 76 
SUMMER VISITANTS- -| 30 32 3! 
113 | 120 | 107 |= ANNUAL BREEDERS. 
WINTER VISITANTS- -| 43 47 50 
PERIODICAL VISITANTS-| 12 17 26 
CASUAL VISITANTS - -| O61 58 47 
ACCIDENTAL VISITANTS| 37 65 60 
266 307 290 |= TOTAL AVIFAUNA. 


This decided superiority of the avifauna of Yorkshire over those 
of the two maritime districts with which alone it is fair to institute 
comparisons, is to be accounted for by a combination of advan- 
tages. In Yorkshire the favourable geographical position of 
Norfolk is associated with its physical advantages and those of 
Northumberland and Durham, and when it is further considered 
that Yorkshire possesses in addition a much greater diversity of 
surface, soil, and climate than either, there remains little reason 
for surprise at the numerical excellence of its fauna. The 
superiority is not merely one of numerical extent. Casual 
and accidental visitants cannot be regarded as true members 
of any fauna, and the ornithological richness or poverty of a 
district can only be gauged by a comparison of the number of 
its residents and regular visitants, and more especially of that 
of the species which breed annually. In this respect too—as the 
table shows—the superiority of Yorkshire is well-marked, demon- 
strating still more forcibly the advantages possessed by the county 
which contains the greatest diversity of surface, a diversity 
ranging in this case from the low carr lands of the E.S.E. to 
the mountains of the W.N.W., with a coast-line affording both 
lofty and rugged cliffs and sandy flats, thus presenting every kind 
