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Contents tagged with chipmunks

  • Rodent “Pests” and How to Deal With Them

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    Tags: rats, mice, squirrels, chipmunks, pests, pest removal

    Created: 10/15/2014      Updated: 8/8/2016

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    First, let’s get one thing straight. Pests are only pests because they’re doing something that interferes with something you want to do. Western ranchers view wolves and bison as pests; pelicans and cormorants are pests to some fishermen while snakes and otter are pests to others; a bobcat is beautiful to most people but can be a pest to a chicken farmer.

    Squirrel in trash can

    That said, rodents can significantly interfere with some of our goals related to our gardens, homes, and health. The range of solutions to the problem is more or less the same regardless of whether we’re dealing with a mouse, vole, chipmunk, tree squirrel, or even a lot of non-rodents.

    Poison

    I don’t like to use poison in most cases. First of all, any poison that can kill one kind of mammal, can kill any other kind of mammal; this includes you, your neighbors, and many pets. Such poisons usually also kill birds, reptiles, and fish. 

    Block of rodent poison

    To reduce the likelihood that “non-target” species will ingest the poison, it is mixed with wax, grain, and flavoring to form a little block that is then put into a plastic box that the rodent has to crawl into to access the poison. However, if the poison killed quickly, the rodent population would eventually figure out that they shouldn’t eat it. Instead, many of these poisons work by making the gastrointestinal tract leaky. Essentially, over time, whatever ate the poison will bleed to death internally.

    Poisoning is a slow death. Worse, the animal may die in a place where a dog or cat, hawk or owl, or some other animal may eat it, then die of secondary poisoning. Assuming the poisoned pest is not eaten, it may die inside your wall or crawl space, often making quite a stink. The stink is relatively short term though and when it goes away you may think all your troubles are over. However, you now have a mummified body in your wall which will attract a wide range of insects, notably the Dermestid.

    Dermestids are a kind of beetle which, as larvae, feed on dead, dry flesh. They will also feed on leather, fur, wool, and many other fibers and textiles. They can very quickly build up large populations even on something as small as a mouse carcass. Eventually they spread through the house and will happily eat that nice jacket you stored away during the summer, or your carpets, even the feathers in your pillow. Having eliminated a single rodent pest by poison, you now have hundreds or thousands of insect pests to deal with.

    Sometimes though, poison is the only solution. It can be used very effectively when deployed and monitored by trained and dedicated people. But, in a household situation, poison is rarely a good solution and often causes more problems than it solves. Instead, try one of these alternatives:

    Trapping

    For a problem that is acute – that is you have a pest currently causing damage – a trap can solve the problem quickly. Snap traps, box traps (like the Tomohawk or Havahart for large animals, or the Sherman for small ones), repeating traps, and sticky traps are all options, but some a better than others.

    Rodent snap trap

    I like snap traps. When baited correctly in a household situation, they rarely capture non-target species. They usually kill cleanly and humanely without any training on the part of the operator. They don’t need to be monitored because either they caught something and killed it or they didn’t catch anything. If you’re afraid of catching your fingers while setting traditional snap-traps, shop around for plastic ones that can be set by simply stepping on a treadle.

    Box traps and repeating traps are very useful but have two problems for the homeowner. They need to be monitored daily to ensure trapped individuals don’t suffer for lack of food and water. Monitoring has the added problem of disturbing the site and reducing trap success. The worst problem though, is that once you catch something, it has to be killed. Most homeowners simply don’t have the skills to humanely and cleanly kill rodents.

    The challenges of monitoring and euthanasia are compounded with sticky traps. From the moment the animal enters the trap, it begins suffering. These traps capture a wide range of non-target species, including reptiles, amphibians, and birds. Vegetable oil can be used to free an animal from the goo but a residue will remain that can impede movement and grooming, and the stress of handling is often enough to kill the animals a short time later. There are small sticky traps with a very thin coating of goo that are designed to aid in insect monitoring. I use these regularly but I don’t see any good reason to use the sticky traps designed to catch rodents.

    In household situations, I advocate strongly for snap traps. Regardless of situation or trap though, trap placement will strongly influence trapping success.

    Steve Sullivan, Senior Curator of Urban Ecology

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  • How to Eat, but Not be Eaten — Foraging Strategies of Four Urban Squirrel Species

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    Tags: squirrel, squirrels, urban ecology, chipmunks, chipmunk, chicago, chicago wildlife

    Created: 9/19/2014      Updated: 8/9/2016

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    The most common tree squirrels in our region are the grey (Sciurus carolinensis) and the fox (S. niger). Both of these species are scatter hoarders. That is, they bury nuts in random places across the landscape. In contrast, the red squirrel (Tamiasciurus hudsonicus) is a larder hoarder. This means they put all of the food they have gathered in only a few places, like a hollow log or under a rock.

    Grey Squirrel digging in the ground

    Grey squirrel caching

    These two strategies have costs and benefits. A larder hoarder can defend its cache from other squirrels, nut and seed eating birds, and many other species that might rob it of food. Even you may have been scolded by a red squirrel when you inadvertently came too close to its larder. On the other hand, there’s not much a red squirrel can do to deter a determined black bear from raiding the squirrel’s cache. Scatter hoarders don’t have to worry about bears but they do lose a lot of their nuts to competing squirrels and birds, and simply because they can’t find the food once it is buried.

    Fox Squirrel eating in a hole in a tree

    Fox squirrel eating

    These two different foraging methods also result in red squirrels having relatively large territories. You don’t often see lots of red squirrels in the same place at the same time. On the other hand, there are many places where you might see more than a dozen grey squirrels foraging together. 

    Red squirrel on a rock

    Red squirrel

    One thing that does bring lots of squirrels together is bird seed. If seed is buried it either rots or germinates. Either way, it is not very useful to squirrels so, rather than run around caching, as they do with nuts, squirrels will simply sit and eat the seed. The threat of predators and more aggressive squirrels keeps them moving around a little but they are otherwise perfectly happy to sit at the dinner table and eat.

    Chipmunks, though, have a different strategy. They have check pouches. This allows chipmunks to literally stuff their faces full of food, then run back to their burrow, dump the food, and return for more once they think the coast is clear. In this way, they can collect plenty of food to eat, while only exposing themselves to the danger of predation for relatively short amounts of time. The seeds they gather are stored in cool, dry rooms (the same way we store grain) so it stays fresh and nutritious through the winter. This foraging strategy is so successful that chipmunks have become our most common ground squirrel in urban areas.

    Have you ever wondered why you don't see baby squirrels as often as you see adult squirrels? Learn why in this post.

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