Working in cooperation witli USDA-APHIS' Bioteclnnology 

 Regulatory Services, NWRC scientists conducted studies to 

 determine digestion and pinysical transport of commercial 

 agriculture seed corn, barley, safflower, and rice by red-winged 

 blackbirds and other species. 



blackbirds, or pigeons. However, birds retained 

 viable seeds in tlieir esophagus, crop, and gizzard. 

 For instance, mallards and ring-necked pheasants 

 retained 228 and 192 barley seeds, respectively, in 

 their esophagus/crop after foraging for 6 hours. Of 

 the seeds recovered from the esophagus/crop of 

 these two species, respectively, 93 percent and 50 

 percent subsequently germinated. 



Birds transported seeds away from the feeding site, 

 but there were only five instances of seeds attaching 

 to the feet or legs of birds. The risk of corn, 

 barley, safflower, or rice germinating offsite when 

 transported by a bird either internally or externally 

 will depend on environmental conditions, soil types, 

 temperature, timing, seed quality, and location. 

 Isolating planting locations away from commercial 

 agricultural crops and migrating birds would reduce 

 the probability of seeds' being transported and 

 germinating in similar sites. 



More research is needed to (1) determine the 

 extent of seed removal by birds from experimental 

 pharmaceutical and industrial crops sites, 

 (2) determine germination rates of seeds 

 recovered from birds after a year-long exposure 

 to environmental conditions, (3) identify the 

 species of birds most likely to visit experimental 

 pharmaceutical and industrial crops sites, and 

 (4) develop a risk model for pharmaceutical and 

 industrial seeds transported and germinated offsite. 



TITLE: Defining Impacts and Developing 



Strategies To Reduce Mammalian Damage 

 in Forested and Riparian Ecosystems 



GOAL: Develop an understanding of the economic 

 and ecological impacts of damage inflicted 

 on forested and riparian systems by 

 herbivorous and omnivorous mammals and 

 develop tools and techniques for reducing 

 that damage. 



Damage to timber resources by wildlife occurs in a 

 variety of environments, ranging from bottomland 

 hardwood forests to upland conifer farms. Wildlife 

 impacts on forest resources can be extensive. For 

 example, attempts to replace trees after a harvest 

 or a fire can be compromised because of foraging 

 wildlife. Reforestation efforts are greatly hindered 

 by bears, beavers, deer, elk, mice, mountain 

 beavers, pocket gophers, porcupines, and voles 

 cutting and gnawing on seedlings. Some of the 

 same species that damage seedlings also damage 

 and destroy established trees after canopy closure. 



Developing nonlethal methods to manage wildlife 

 damage is a priority in the ongoing research 

 conducted at NWRC's Olympia, WA, field station. 

 Scientists are conducting research to develop 

 alternatives to lethal control, including physical 

 deterrents, repellants, frightening devices, habitat 

 and behavior modification, and improved capture 

 methods. 



NWRC Scientists Develop Integrated Approach for 

 Managing Mountain Beavers — Trapping is currently 

 the most common and effective method employed 

 for controlling mountain beaver damage. However, 

 research conducted by scientists at the NWRC 

 Olympia field station demonstrated that the effects 

 are short lived. Mountain beavers often reinvade 

 newly harvested units in just a few weeks and are, 

 therefore, present when new seedlings are most 

 vulnerable to damage. Scientists at the field station 

 have also conducted research to develop a baiting 

 strategy for reducing seedling damage by mountain 

 beavers in reforested areas. 



14 Developing Methods 



