Another method of capture was to hunt at a nesting colony, particularly during the period of a few days after the adult pigeons abandoned their nestlings, but before the nestlings could fly. Some hunters used sticks to poke the nestlings out of the nest, while others shot the bottom of a nest with a blunt arrow to dislodge the pigeon. Others cut down a nesting tree in such a way that when it fell, it would also hit a second nesting tree and dislodge the pigeons within. In one case, of large trees were speedily cut down to get birds, and such methods were common. A severe method was to set fire to the base of a tree nested with pigeons; the adults would flee and the juveniles would fall to the ground. Sulfur was sometimes burned beneath the nesting tree to suffocate the birds, which fell out of the tree in a weakened state. By the mid-19th century, railroads had opened new opportunities for pigeon hunters. While previously it had proved too difficult to ship masses of pigeons to eastern cities, the access provided by the railroad permitted pigeon hunting to become commercialized. An extensive telegraph system was introduced in the 1860s, which improved communication across the United States, making it easier to spread information about the whereabouts of pigeon flocks. After being opened up to the railroads, the town of Plattsburgh, New York is estimated to have shipped 1.8 million pigeons to larger cities in 1851 alone at a price of 31 to 56 cents a dozen. By the late 19th century, the trade of passenger pigeons had become commercialized. Large commission houses employed trappers (known as "pigeoners") to follow the flocks of pigeons year-round. A single hunter is reported to have sent three million birds to eastern cities during his career. In 1874, at least 600 people were employed as pigeon trappers, a number which grew to 1,200 by 1881. Pigeons were caught in such numbers that by 1876, shipments of dead pigeons were unable to recoup the costs of the barrels and ice needed to ship them. The price of a barrel full of pigeons dropped to below fifty cents, due to overstocked markets. Passenger pigeons were instead kept alive so their meat would be fresh when the birds were killed, and sold once their market value had increased again. Thousands of birds were kept in