Several other kinds of small birds now go in flocks, and among others the
large Senegal swallow. The presence of this bird, being clearly in a
state of migration from the north, while the common swallow of the
country, and the brown kite are away beyond the equator, leads to the
conjecture that there may be a double migration, namely, of birds from
torrid climates to the more temperate, as this now is, as well as from
severe winters to sunny regions; but this could not be verified by such
birds of passage as ourselves.

On reaching Mazaro, the mouth of a narrow creek which in floods
communicates with the Quillimane river, we found that the Portuguese were
at war with a half-caste named Mariano _alias_ Matakenya, from whom they
had generally fled, and who, having built a stockade near the mouth of
the Shire, owned all the country between that river and Mazaro. Mariano
was best known by his native name Matakenya, which in their tongue means
"trembling," or quivering as trees do in a storm. He was a keen slave-
hunter, and kept a large number of men, well armed with muskets. It is
an entire mistake to suppose that the slave trade is one of buying and
selling alone; or that engagements can be made with labourers in Africa
as they are in India; Mariano, like other Portuguese, had no labour to
spare. He had been in the habit of sending out armed parties on slave-
hunting forays among the helpless tribes to the north-east, and carrying
down the kidnapped victims in chains to Quillimane, where they were sold
by his brother-in-law Cruz Coimbra, and shipped as "Free emigrants" to
the French island of Bourbon. So long as his robberies and murders were
restricted to the natives at a distance, the authorities did not
interfere; but his men, trained to deeds of violence and bloodshed in
their slave forays, naturally began to practise on the people nearer at
hand, though belonging to the Portuguese, and even in the village of
Senna, under the guns of the fort. A gentleman of the highest standing