472 REPORT—1896. 
described as partial migrants. During the prevalence of fine weather or 
of weather not ungenial for the time of the year, these emigrants slip 
away gradually and almost unobserved, except by those favourably 
stationed on and off our coasts, by whom land: birds are only seen when 
migrating. The pulse, so to speak, of these movements is, however, from 
time to time manifestly quickened under the influence of ungenial 
weather conditions of a not too pronounced nature, the chief stimulant 
being a fall in the temperature. 
Even JULY, in certain seasons, has its ungenial spells, and so it was 
in the years 1882 and 1883, which were remarkable for their periods of 
unseasonable weather. These outbursts make themselves felt on our 
feathered population, and result in movements of a partial nature, per- 
haps, but which have left their mark on the migration record. The 
weather influences inciting these incipient movements are a com- 
plete break-up of genial and normal conditions and the prevalence of 
unsettled conditions, not unfrequently accompanied by thunder and heavy 
rains, and a decided fall in temperature. The result upon our summer 
visitants, or it may be upon their young, is that many of them move from 
their accustomed haunts, and appear on the coast at the light stations 
—sometimes at the lanterns—where their occurrence is duly chronicled. 
The species chiefly affected are the *Thrush, *Redbreast, Wheatear, 
*Whitethroat, Willow Warbler, Swallow, Martin, *Swift, and *Cuckoo.! 
During Aucusr the ordinary emigratory movements of the autumn 
set in, and are usually performed under ordinary conditions—namely, fine 
weather. The weather influences other than normal are the same un- 
genial spells, especially if accompanied by cold, alluded to for July. 
These, however, are not frequent in most seasons, and yet no season is 
entirely free from them. 
With the great increase to emigration that characterises SEPTEMBER, 
there are recorded, usually on several occasions during the month, very 
decided movements which may be fairly termed emigratory ‘rushes.’ 
These occur simultaneously with the weather spells which, among other 
characters, are remarkable for a decided fall in temperature, sometimes 
amounting to many degrees. In one instance, on September 15, 1886, 
the difference in temperature amounted to as much as 20° in twenty-four 
hours, and naturally produced a marked effect in the emigration returns. 
The conditions causing such decided falls in the thermometer, in the 
great majority of instances, are northerly winds, and as these may be due 
to anticyclonic weather conditions their force is usually slight. Some- 
times, however, these cold spells prevail with a light southerly wind. 
This was the case on September 5, 1885, when a cold, showery period 
caused much emigration. That low temperatures are the prime factors is 
clearly demonstrated by the September records ; inasmuch ‘as during 
this month there are unsettled periods which are not characterised by 
cold, and it is found that their influence on migration is comparatively 
insignificant. When the unsettled periods become very pronounced or 
develop gales, which is sometimes the case during this month, the weather 
barrier thus formed arrests the emigratory movements, which are ren- 
dered impossible under such adverse conditions. 
The great autumnal emigratory movements, however, occur late in 
' Those marked thus * are recorded as having been killed at the lanterns during 
this month. 
