Like all garden pests, the management of mammalian and bird pests comes under the banner of integrated pest management. That is to say, we use a variety of techniques and methods to reduce the damage caused by these creatures in our gardens. Our goal is not total eradication and elimination, our goal is to keep the pests at a reasonable level and live with them in an uneasy balance and precarious harmony.
We generate and waste a lot of excess food, and create movement and disturbance wherever we go. As a result, creatures that enjoy our presence thrive alongside us. Without planning for it, we provide them with food and shelter. And what more can you ask for?! This is true for weeds and bugs, as well as larger animals like rodents, coyotes, skunks, pigeons and sea gulls. In old old native times, food and the density of people was pretty well matched. Some years the acorn crop was lean, others years the salmon were abundant. There was an ebb and flow to the cycles. The amount of food was constrained by the climate and weather, dependent on the water and rains, and fluctuated year to year dependent on health and disease.
As the country got flooded with settlers, they took to shooting and eating darn near everything that moved. Especially if there was a famine or a drought and the crops failed them. Plus people were hankering for meat in the markets. For a whiles there, every animal ended up in a pan, a pot, or in the side of a ditch. Then, luckily, at some point, folks realized that this was not going to be good in the long run, and enacted game laws, anti poaching laws, plus created wild life conservation areas and reserves. To keep up with the demand for animal protein, we boosted the production of domesticated animals like chickens and hogs, and cultivated acres and acres to grow fodder crops for the animals to get fat on. Fields of grain, alfalfa and corn, soy and so on.
In cities where many people now live, most people don’t hunt or trap, and are often pretty averse to the very act of killing or slaughtering an animal, even if they have a slab of one on the plate almost every day. So its a bit of a sensitive topic. When mammalian pests invade the home, some people will resort right away to poisons, or to traps. These methods are readily available at the hardware store. More often than not, other people will call the pest control company for some advice and a round up of the small beasts perturbing the peace.
Do note that for some animals, there is no protection. There is no Society for the Conservation of the Brown Rat nor the Roof Rat Chapter of California. You can kill as many as you want of these guys, and it is unlikely anyone will knock on your door or protest your actions. On the other hand, it is illegal to kill seagulls because they are protected under the Migratory Bird Treaty of 1918. As are most birds. That did not stop Greg’s hungry sailor buddy from making seagull soup in the Sausalito harbor back in the day, but just to imagine the taste of that meat and broth is enough to make you want to take a really long solitary walk in a hot desert. For other animals like the crow, there is a hunting season on em; here it runs from around December through April. And sometimes you can request special permission to hunt certain animals as a nuisance. In a city, it is illegal to go shooting guns because of the potential for injury. So you would have to use a bow and arrow, or try to run and grab one with your bare hands. Check the city ordnances and find out what is on the books before you do anything silly and suspect that will land you in hot water.
Back to IPM. We roughly classify the methods of control into four categories. Physical (direct action kill or trap), cultural (preventive ways to keep animals out and away), biological (find an animal that will eat your pest animal, maybe you), and chemical (poisons and things of that nature).
For the most part, cultural is the number one method. If you put all the food away, and do not give the animals a place to live, they will go elsewhere. But in a garden, how do you put all the plants away so that the deer cannot eat them? What happens if the plants you are enjoying are the food?! And if their home is the very dirt in the garden, short of removing all the dirt and filling it all with concrete, what can you do? This is the dilemma. Screens, stainless or plastic netting and wire, electric fencing – they can do the trick. Raised beds, unpalatable plants also. Predator urine and blood, foul smell from castor oil bean extracts, fake owls, sonic noises, icky ick things that repel the animals, all potentially useful. A Jack Russel terrier or a beagle, that might do it. Not always though, like when a whole family of eight raccoons decides they really like that bowl of wet cat food on your back porch.
Traps and the back side of a shovel. These are number two – physical controls. But first you have to catch em. And that means identifying the culprit, finding out where and when they are active, and then somehow hunting them down. That is what it takes. For the most part, nobody cares that much about the rodents. Except there were protests for a while against gardeners killing gophers, and they set up a ten block stretch in Golden Gate Park where it was forbidden to catch them. Not sure if the gophers needed much help, but that is how it goes sometimes. When it comes to a little bit larger and some would say cuter mammals like squirrels, skunks, and raccoons, that is where it gets tricky. The old time gardeners would get calls about them, trap them, then just go ahead and release them into the wild somewhere nearby like the Presidio or San Bruno Mountain – which is not that far away from wherever they came from. A short happy night stroll later they would be right back where they started. Or they would be disoriented and fall fast victim to an asphalt roadway and steel belted radial tires. If you have a trappers license or are a certified pest control operator, you are supposed to catch them and put them down right away (kill them), you are not supposed to move them around. But sometimes, they just let the animals go again after they’ve been paid for their services, out of laziness or compassion or what have you. Then the animal is on the loose, again. Do note that wild animals can and do carry a number of worm parasites, invertebrate hitch hikers, as well as diseases that can affect humans in a negative way. Yes there is still the bubonic plague bacteria around here, hanta virus in the rat droppings, rabies, lyme disease once in a while from the ticks, etc. Friends in more rural places say there are not that many raccoons out in the country. Likely because there is not as much food in the wild as there is next to the garbage cans and dumpsters here in the city. Plus the comfy warm crawl spaces and rain-free under-the-deck four star accommodations. Lack of mountain lion or eagle predation earns another star. Then what do you do? What can you do? Most of the time people do nothing, which is not productive really and not helpful either. Sometimes you hear about some crazy hungry gardener that speared a raccoon, made a hat with its skin, and ate its meat over a barbecue with friends. But that is rare and almost unheard of in our modern world today. And in general not recommended for the reasons already stated above.
Biological methods often work for other pests of the garden, whether that be mites or aphids. You can go ahead and buy some beneficial insects online from an insectary, creatures like mite predators or nematodes or even praying mantises. They work. And chickens or ducks eat the slugs or snails too. But who is going to eat a 12” rat or attack a skunk? Great horned owls are predators of skunks but it is unlikely you can encourage it to come and eat that exact skunk that is camped out under your ipe ironwood boardwalk. And there are not enough peregrine falcons or hawks to eat all the pigeons under the freeway overpass. So for the most part, pass on biological control of the larger mammals and birds. Unless you are dreaming of coyote. But dens and dens of coyotes roaming in a dense urban metropolis poses its own set of challenges….For sure they will not only attack the pests. They will pick on the easy well fed cat that is playing in the yard, or the little three year old kid rolling a ball on the lawn while the parents are looking at their cell phone.
Last but not least are the poisons. For the most part these are ingested (eaten as bait), but in the old times poisonous gases like the tail pipe exhaust of a vehicle, or the sulfuric smoke from a flare would count in this category as well. Fumigants they call them. They are okay, and if you look at any public institution or commercial center you will notice the black plastic boxes full of rat poison. Still, come out at night in a densely inhabited place with food and water and you will see the shiny beady eyes of the rats. Lots of them. They will be here as long as people are here, likely longer. I won’t go into the chemical mode of action of particular poisons here. Just keep in mind that rodents can readily evolve resistance to our chemicals over generations of selection, and that whatever poisons we put out into the world work their way up and to the side of food chains. That is all for now. Good luck keeping mammalian and bird pest at bay in your garden.
Mission Azul 