It exists in immense numbers, and is a grand destroyer of all insects.

On this account it is seldom or never shot at, especially as it is a great comforter to all cattle, whose hides it entirely cleans from ticks and other vermin, remaining for many hours perched upon the back of one animal, while its bill is actively employed in searching out and destroying every insect.
During the prevalence of the cholera at Mauritius these birds disappeared.

Such a circumstance had never before occurred, and the real cause of their departure is still a mystery.
May it not have been, that some species of insect upon which they fed had likewise migrated, and that certain noxious animalcules, which had been kept down by this class, had thus multiplied within the atmosphere until their numbers caused disease?
All suppositions on such a subject must, however, remain in obscurity, as no proof can be adduced of their correctness.

The time may arrive when science may successfully grapple with all human ailments, but hitherto that king of pestilence, the "cholera," has reduced the highest medical skill to miserable uncertainty.
Upon reconsidering the dangers of fevers, dysentery, etc., in the swampy and confined districts described, the naturalist may become somewhat less ardent in following his favorite pursuit.

Of one fact I can assure him that no matter how great the natural strength of his constitution, the repeated exposure to the intense heat of the sun, the unhealthy districts that he will visit, the nights redolent of malaria, and the horrible water that he must occasionally drink, will gradually undermine the power of the strongest man.