Exposure to parasites (ie: fleas, ticks).Some animals difficult to handle (scratches, bites).Must be checked often (especially in extreme weather).Some animals (ie: feral cats) may injure themselves trying to escape.Non-targeted species may be caught in seasons where food sources are scarce.Easy and safe to release captured animals.Safer way to handle feral or rabid animals.They are often used for relocation by conservation departments, as well as for wildlife sampling and tagging. These traps are often used for larger animals than pitfall traps, such as foxes, possums or feral cats and dogs. Cage traps can be entered from one side or both, depending on the trap. The animal applies pressure to a tray on the floor of the trap, which sets off a spring-loaded mechanism, releasing the door over the trap entrance. Bait can be olfactory (urine, meat, animal droppings), visual (feathers, lures) or auditory (field attraction phonic device). It coaxes the animal into the trap using bait. Place board or slate to cover trap (keeps out rain and predators)Ĭage trapping is another form of live trap.Container should fit snugly in hole without gaps.Dig a hole the width and depth of the container.Can not be used to determine accurate population sizes.Many factors influence effectiveness (weather, activity level).Do not prevent conflict between trapped animals.Daily behavioural patterns and community interaction can also be studied using pitfall traps. Pitfall traps are useful in studying distribution patterns of different species, especially when comparing microhabitats. Barriers, such as a drift fence, can be used to coax animals toward traps.Bait can be used to attract a certain group of individuals.When used in wildlife surveys, animals are typically trapped randomly, and stumble into the pit accidentally.Animals can become trapped by various mechanisms. Prolonged cool rain during emergence also helps control numbers.Discussed are three types of trapping: Pitfall, Cage, and Elliot traps.Ī pit or pitfall trap is a container that is placed into the ground so that the edge is level with the soil. Check the traps frequently and count needle midges to get an idea of population numbers. Place the traps with the jar side facing between rows so it gets as much light as possible. Placing five emergence traps per field of trees is good for monitoring a growing area. The degree-day models can help determine when to place traps. The needle midge is one of the few pests for which there are degree-day models to track emergence, which can vary by 4 to 5 weeks from year to year (Appendix E). Needle midges seem to prefer the “shady side” of trees, where there may be some vegetation however, in a fully stocked field, this could be anywhere. Pay particular attention to Douglas-fir fields that had Douglas-fir needle midge problems the previous year and to edge rows close to native Douglas-fir timber. See the section on Douglas-fir needle midge for suggestions on the design and timing of traps. The jar will contain other flying and crawling insects, so use a hand lens to help with identification. Place a moist towel inside the jar to catch the adult midges. As adults emerge from the soil, they fly towards the light (jar) to escape. Needle midge traps consist of a box with a jar inserted into the top edge of one side. (Photo by Jack DeAngelis, Living with Bugs.) Ground nests can pose hazards to shearing crews and visitors, so control is also beneficial for safety. Direct spraying of ground nests is allowed traps may be useful in finding these ground nests. There are currently no registered insecticides that may be used as toxic bait to eliminate the nest. Since the queen does not move outside the nest after this early period, later trapping only affects the worker population. Thus, early lure placement and trapping should help control some colony formation. The queen is the key to controlling population growth, and she only flies in March. Placing roughly 5 traps per 10 acres of field is sufficient for monitoring. Yellowjackets are the only Christmas tree “pest” for which there are specific chemical lures for attraction. They are useful for monitoring worker activity but not for control. These traps are less successful with German yellowjackets. Yellowjacket attractant traps include chemical lures, colors, and trap designs to attract western yellowjackets. (Photo courtesy of Oregon Department of Agriculture.)
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