PALLAS'S SAND-GROUSE 
167 
and “self” fertilisation, that the former was the best, and that 
the latter was very bad ; but he overlooked an important point. 
“ Crossing ” is a temporary, not permanent, stimulus. Florists 
get finer and more vigorous plants, handsomer flowers, greater 
variation in colours, &c., and at first more seed, but they soon 
get to the end of their tether. In a few years the “best” 
flowers set no seed, or very little, or it is very difficult to secure 
it ; and they not infrequently lose their plants altogether if they 
are such as cannot be grafted. It is by this means, or by bulbs, 
as in hybrid narcissi, that they are often alone able to preserve 
the “ improved ” plants. 
PALLAS’S SAND-GROUSE. 
FTER a lapse of eleven years England has again been 
Rra’® visited by a flock of Pallas’s sandgrouse, and their 
RwJWl arrival naturally excited much interest in ornithological 
circles. Our knowledge of the causes of bird migration 
is, in spite of extended observations and investigations, still so 
slight that no satisfactory reason can be assigned for the rare 
irruptions of this peculiarly Central Asian species into Western 
Europe. There is little doubt that the sand-grouse have for 
centuries been in the habit of making spasmodic excursions 
beyond the limits of their desert home ; but until 1848 they 
were quite unknown in Europe. In that year a single specimen 
was taken at Sarepta on the Volga. Five years later several 
examples occurred in the same district, and in May, 1859, a pair 
is said to have been killed in the Government of Vilna, on the 
eastern borders of Russia. In the same year a few specimens 
were seen in Western Europe — one in Jutland, another in 
Holland, two in England, and one in Wales. Two months 
after the pair were taken in Vilna, a solitary example was shot 
at Walpole St. Peter, in Norfolk, this, I believe, being the first 
recorded occurrence of the bird in the British Isles. In the 
following year another specimen was obtained in Sarepta. 
These isolated instances attracted little more than local atten- 
tion : it was not until 1863 that an event took place which has 
been pronounced “ the most remarkable fact that has ever 
occurred in the history of ornithology.” This was the invasion 
of Western Europe by a “host” of Pallas’s sand-grouse, esti- 
mated by Professor Newton to have numbered no less than 700 
birds. 
A large flock of these birds arrived in England somewhere 
about the 21st May, and a few individuals strayed as far as 
Ireland. By far the greater number, however, appear to have 
remained in our Eastern Counties, where they divided them- 
selves into flocks, ranging from seven to sixty birds, and 
frequented, for the most part, sandy fields and tracts of heath- 
