The number of water-birds in the _pantanales_ bordering the upper Paraguay is almost unbelievably large. There were such countless thousands of cormorants and anhingas that they confused the eye. Colonel Roosevelt never permitted useless slaughter, and when one day, one of the _camaradas_ forgot himself and shot a bird, he was compelled to go for it in a rowboat; then the bird was skinned and preserved. After that no one ventured to shoot at the winged hosts. Egrets were present in such vast numbers that the trees were white with them; and when they flew the twinkling wings filled the air like snowflakes. They were not molested in this locality for the reason that their habitat is impenetrable. I later learned in another region that thousands of these birds are killed for their plumes, in a most atrocious manner. About the time the egret’s feathers are at their best, which is also the time when the nests are filled with young birds, the annual floods have begun to recede, leaving small lakes and marshes teeming with imprisoned fish, such as we had seen _en route_ to Rancho Palmiras. This is the season of harvest for the water-birds, and they repair daily to some favorite resort to gorge on the luckless fish. The plume-hunters, taking advantage of this combination of circumstances, collect quantities of fish, poison them, and then scatter them over the birds’ feeding-grounds. Occasionally poisoned shrimp are used if the inundations extend beyond the usual time. This method is, of course, cheaper than shooting; the birds are not frightened away as they are by the loud reports of guns, and the success of such relentless persecution must be obvious. A whole colony could be exterminated in its feeding-grounds even if the rookery is impregnable. São Luis de Caceres was reached January 5, and at noon the next day the _Nyoac_ weighed anchor again and started up-stream. A short stop was made at a small landing called Porto Campo, where a few days’ hunt produced tapirs, deer, and white-lipped peccaries. January 13 found the expedition aboard a launch, struggling against the swift current of the Sepotuba. A heavy house-boat full of provisions and luggage was towed alongside, and we made not over a mile an hour. The end of the river journey came on January 16. We had reached Tapirapoan, the farthest outpost on the frontier, and immediately preparations were begun for our long dash across the _chapadão_ of Matto Grosso. CHAPTER XV A FORTY DAYS’ RIDE THROUGH WILDEST MATTO GROSSO