The winter quarters of the Shoshone were more secure from enemy attack, however, than were those of the Bannock. The only hostile tribe to enter southern Idaho with any frequency was the Blackfoot. They pressed their attacks vigorously, especially against the Bannock, and were a subject of some wonder owing to their practice of sending out war parties in the middle of winter. Blackfoot war parties, consisting only of men, frequently came south from Montana before the passes were closed by the winter snows and made camp on Henry's Fork, near the present site of St. Anthony, Idaho. From this convenient point they sent small raiding parties against the Bannock camps. The main purpose of these raids was to capture horses, which were driven north to the Blackfoot country when the passes opened in the spring. Although the Bannock were kept on the defensive, they were not the helpless prey of the Blackfoot. Defensive tactics were frequently too late, for the enemy drove off horses surreptitiously by night, but counterraids were made and pursuit was given in return. The Blackfoot occasionally pressed their raids farther downstream and entered the Portneuf Valley, but such forays were less frequent. Historical records, however, mention Blackfoot raids in Yellowstone Park and Jackson Hole and as far south as the valleys of the Green and Bear rivers and Great Salt Lake. When spring arrived the winter camp broke up and both Shoshone and Bannock split up into small groups, each of which went their separate ways. Hunting was the first undertaking after breaking up winter camp. The spring hunt was usually conducted in Idaho rather than in more distant places, since most people wished to return later in the spring for salmon fishing at Glenn's Ferry. Small parties of only a few lodges each roamed through the mountains of Caribou County, Idaho, in search of deer and elk, while others went southwards into the Bear River and Bear Lake country. Chub were caught in Bear River, and duck eggs were gathered and ducks killed in the marshes at the north end of Bear Lake. During the spring wanderings, roots were dug also. The route to Bear River went through much the same country as modern U.S. Highway 30 N. Parties ascended the Portneuf River and crossed the divide to the Bear River at the site of Soda Springs. They continued south on the Bear River to Montpelier. Those who did not intend to return for salmon but wished to visit the Eastern Shoshone ascended the Bear River to Cokeville and Sage and crossed the Bear River Divide, passing the fossil-fish beds en route.