OUR MIGRANTS. 185 
we cannot understand it, but we can at least admire the beauty 
and harmony which pervade the whole of nature in its every 
form and aspect. 
I purpose in these few notes to refer to some of our well-known 
British migratory birds—the period of their appearance and de- 
parture, and, so far as may be known, their habitat in foreign lands. 
Of all our summer migrants the Swallow tribe, known to orni- 
thologists as the Zirundines, would appear to occupy the prominent 
place: scarcely a schoolboy but looks out for the first Swallow, and 
notes the date of its arrival, watches with interest the new 
comers betake themselves to their accustomed haunts, the 
building of the wonderful nest of mud under the favourite eaves, 
the feeding of the young ones, the congregation of the species in 
autumn, and their apparently sudden departure for distant 
lands. The Swallow and Martin usually arrive in the beginning 
of April. Their sojourn during the English winter is made 
chiefly in Africa, but probably not further south than the 
Tropics. Here they remain till the changing seasons impel 
them northwards, their line of flight being across the Medi- 
terranean into France and Spain, and thence across the English 
Channel to our own Island. During August and September 
they assemble together in vast numbers, and these are constantly 
being swelled by the young broods as they leave their nests and 
_ take to flight. The osier beds about the Thames are a favourite 
roosting place. In October the great exodus of Martins takes 
_ place; silently they come to us, and suddenly they go, their 
numbers vastly increased since their arrival among us. A few only 
remain behind, and these soon vanish, so that a Martin in 
November is a great rarity. Last year I saw two as late 
as the 16th of November, which is one day later than I had pre- 
viously observed them. A few days after the general departure— 
and the great bulk of our summer visitants are flitting about tho 
western region of Africa, insect hunting on the Niger’s stream, 
or domesticating themselves among the people of Timbuctoo. 
‘The favourite theory of Gilbert White, that vast numbers of the 
‘Swallow tribe remained in holes and hiding places, even under 
“water, in a torpid state, ig one which findg little favour with 
