Vertebrate Pest Conference Proceedings collection
Date of this Version
September 1984
Document Type
Article
Abstract
Performance of three models of sodium cyanide (NaCN) ejectors was evaluated at Port O'Connor, Texas, early in 1982. M-44s, M-50s, and coyote getters were test-pulled and reset at 7-day or 21-day intervals for 42 days. Each pull was recorded as good if, in our judgment, it would have taken a coyote. Based on 402 to 430 test pulls of each ejector model, the percentages of good pulls were 40% for M-50s, 73% for M-44s, and 99% for coyote getters. M-44s with shortened plungers performed better than standard M-44s. Most pulls of M-50s resulted in ejection failure due to corrosion between the plunger and ejector body. The greatest problems with M-44s were mechanical defects, particularly of triggers, and caking of NaCN in the capsules. Condition of NaCN was evaluated in 1,354 M-44 capsules that had been weathered for one to six weeks. Eighty-five percent contained normal, dry powder after one week and only 49% were normal after six weeks' exposure. Addition of a beeswax seal decreased capsule deterioration. Based on these results, we recommended that the Service discontinue the M-50 and concentrate on improving the M-44. The Service's Pocatello Supply Depot has shortened the M-44 plunger and added a beeswax seal to M-44 capsules made for use by the Animal Damage Control program.