474. REPORT—1896. 
registered for any spring migrants during the eight years of the inquiry. 
It is noteworthy to find, from the ‘ Daily Weather Report,’ that this 
portion of the British area was the warmest spot in Western Europe on 
the date in question. 
During genial intervals in March, summer birds arrive, the Wheatear 
appearing some years in considerable numbers. In 1884, during a 
prolonged spell of warm weather, exceeding in warmth anything recorded 
tor very many years, which followed a period of sharp frosts and snow, 
no fewer than six species of spring migrants were recorded as arriving in 
our Islands. Again, in 1886, five species were noted for a similar genial 
period. On the other hand, in the cold wintry March of 1883 one summer- 
bird alone—the Wheatear—was noted. Another March colder than the 
average was experienced in 1885, during which the arrival of three species 
only was chronicled. 
Since the first arrivals of the summer birds appear, asa rule, in March, 
it may here be remarked that the climatic peculiarities of the British area 
would appear to play an important part in the geographical distribution 
of these early immigrants. 
The remarkable fact that the great majority of the summer visitors to 
our Islands are first observed on the shores of the south-west of England 
and Ireland, has already been mentioned. This holds good even in 
ordinary and genial seasons, but in cold ones it is almost entirely the 
case. Thus in March, 1887, with its monotonously low temperature, the 
arrival of six species was recorded on twelve occasions, a// for the south- 
west. During the exceptionally cold and rough March of 1883, only one 
species—the Wheatear—was observed on two occasions, both at stations 
on the west coast of Ireland where the temperature was highest. Again, 
in the cold March of 1885 every record but one of the fourteen chronicled 
was made in this same mild region of the British area. 
It must not, however, be supposed that the thermometric conditions 
prevailing in our Islands are the cause of the northward movements to 
Britain and Ireland in the spring. We must seek their cause in weather 
conditions and influences prevailing and acting in regions to the south of 
our Islands. 
A careful comparison has been made between the migrational and 
meteorological phenomena in connection with these spring emigratory 
movements from the continent. As the result it has invariably been found 
that all such movements, except those performed late in the season, are to 
be correlated with a rise of temperature in south-western Europe and 
perhaps in northern Africa. That this induces the birds to embark on 
their northward journey does not admit of doubt. It is worthy of note 
that in not a few instances such movements are recorded for dates on 
which the temperature in our Islands was lower than immediately before 
the immigration. This clearly indicates that the increase of warmth at 
the seat of emigration is the main factor controlling the spring move- 
ments to the north. This rise in temperature in south-western Europe 
may, and sometimes does, extend to and prevail over the British Isles. 
Apart from this simple phenomenon no other peculiar meteorological 
condition appears to be. associated with these spring movements from 
southern Europe to the British Islands. 
Spring Emigration from Britain.—The movements of birds from our 
Islands to the northern breeding grounds in spring are influenced by the 
weather conditions which prevail in the British area, as all our emigratory 
