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Rat poison from pot farms is poisoning owls, study finds (sfchronicle.com)
149 points by anigbrowl 5 days ago | hide | past | web | favorite | 67 comments

> on illegal farms on private property

There's been a lot of media hand-wringing recently about ecological damage caused by illegal cannabis grows. I'm not exactly sure why, as it's not relevant to any policy debates.

Marijuana can and should be grown organically and sustainably, there's nothing about the plant which complicates that beyond perhaps the need to prevent pollination.

> There's been a lot of media hand-wringing recently about ecological damage caused by illegal cannabis grows. I'm not exactly sure why, as it's not relevant to any policy debates.

If policy is about harm reduction then harms done under current policy are absolutely relevant.

That’s what should be focused on. The primary reason that there are illegal grows causing harm is that there is a mismatch between government cannabis policy and cultural and market reality.


Yes, and marijuana laws are just like slavery, child labor, and littering.

It's ironic because you mention slavery while not understanding the war on drugs is crucial to the health of modern slavery, and drug laws are just as much a human rights issue as slavery laws.

On the contrary, I absolutely oppose marijuana prohibition, and agree that the way on drugs is responsible for a broad variety of social ills, including a hyper inflated incarceration rate.

I think it's a mistake, however, to oppose regulation of legalized marijuana grows by default. Like any other industry, it's going to have potential for negative impacts, and regulation can help check those impacts.

I don't mean to chastise, but there are definitely better ways of expressing that sentiment than seemingly equating slavery with marijuana legalization.

Except many of the illegal growers diverting water to their crops illicitly. Not as big an issue now but during our drought...

I don’t think weed is that high on the list of “agricultural uses of water”. Try almonds or meat

>Marijuana can and should be grown

This is illegal in the US, which includes California.


Like, are you sincere? California, among many other states, has legalized cannabis. https://en.wikipedia.org/wiki/Adult_Use_of_Marijuana_Act

The main environmental impact comes from the plants high water consumption which for a grown up plant is a bit over 20 litres per day. Thats when growing in soil. Hydro weed needs much less water but doesn't taste so good.

Hydroponic doesn’t taste as rich and earthy as organic soil-grown, but it is not considered substandard. You can get a very high-quality product hydroponically, or low-quality in soil. The people who are concerned are connoisseurs, like the same crowded that would buy local organic heirloom tomatoes and get craft beer on tap.

Where does your 20L/day figure for a single grown plant come from? That sounds absurdly high, given the size of a grown plant. I admit I have no domain knowledge, so I'm prepared to be wrong (and surprised). But I'd like a citation or some kind of source for that order of magnitude.

People that grow for quality over quantity can produce some prodigious pot plants. 20L/day is right about in line with what is described here: https://hightimes.com/grow/giant-plants-of-southern-oregon/

Not to nitpick too much, but the article describes 15-19 liters (4-5 US gallons/day average):

> each plant gets about four 5-gallon buckets of water every four or five days

Nitpicking aside, the plant that article describes and pictures is very, very large (i.e., an artifact of the 6 plants per farmer limit imposed by that particular state law).

I don't believe those plants are typical for farmers who do not have to follow six-plants-per-person laws. It seems misleading to suggest that the typical plant requires 20L/day based only on the data point of these huge plants.

Using plants as a measurement of quantity of product produced is misleading, full stop. As long as we continue to legislate limits on plant quantity and not bud quantity (not that I think we should, only that it would be superior) we will continue to promote unhealthy industry practices. For growers who are worried about plant quantity (this was still very much the case even among most "professional" growers this season in Cali, for example, because the first thing cops do is count your plants) 20L/day during the height of the summer months isn't out of the ordinary at all, I know many growers in norcal do 10 gallons a day or more, depending on the soil.

But the original point, that marijuana is hugely wasteful of water, is pretty ridiculous when you compare it to other crops. Everything uses a lot of water. And saying that indoor is better because it uses less water ignores the extreme amount of waste created by using (and climate controlling for) indoor lights.

It seems like this is less of an impact than many crops. Traditionally, grow operations have flourished in places like British Columbia, Washington, Oregon, and the "Emerald Triangle" of coastal/wooded Northern California. I have no particular knowledge about how the plants grow, but I assume this means they grow well in those climates (not that they're merely more tolerated in those locales).

Therefore, an outdoor grow operation could probably done with minimal irrigation and no real impact on drinking water supplies.

Canabis Sativa is from hotter climates but Canabis Indica is from colder places. The best strands are hybrids that try to select the best properties from each natural variety.

How much water do almonds need?

How much water in the US is used to grow almonds? How much water would be needed to grow weed for every man, woman, and child in the US?

Two wrongs don't make a right.

One can argue that both almonds and cannabis take a harmful share of water in drought-prone areas and that both will be controlled.

To the extent that either is a problem, the solution is market-pricing water. High water use farms will move out of drought prone regions for basic economic reasons.

If this is rhetorical, and you know the answers, do share. Because I have no idea. It sounds like you do?

Additionally: why are those numbers relevant? Just for context?

Almonds are brought up because they take up 10% of California's water (https://newrepublic.com/article/125450/heres-real-problem-al...).

A single almond takes 1.1 gallons of water (http://www.motherjones.com/environment/2014/02/wheres-califo...) to produce.

Any argument for limiting marijuana growing based on "it takes lots of water!" has to address why we already permit stuff like almonds to be grown in drought-prone areas.

Ok I can hardly compare “x litres per plant per day” vs “n gallons per almond”. How long does a plant live and how many “portions” does it have? I can guess almonds would be, say, a handful for a “portion”? So that’s.. how much in litres?

See this is why I’m not super stoked about that original comment. Instead of making a clear point, I just get thrown some random hints and a “you go figure it out”. It’s like I’m supposed to make ones argument for them, and it might turn out to be completely irrelevant (maybe almonds are orders of magnitude more [e:less!] thirsty!) and then I can’t even reply because the actual argument was never made!

Just give me the numbers. Do your own homework :) (well, not you, but op)

(Edit: as someone else mentioned, this is assuming op was being rhetorical. If it’s a genuine q: I completely second it)

I know almonds take up a TON of water in an area without a ton of water.

I do not really want to do the math, but if you are worried about the water usage of weed, I do implore you to first look up the water usage of almonds.

Thanks, but no thanks. I’m not keen to do the homework for your argument.

[e: I’m not saying this to be petty, my point is this is not a strong argument. It’s a common occurrence, and a pet peeve of mine. I can imagine it feels right—in fact I also believe you are probably right! But were I of the opposite inclination, this wouldn’t convince me.]

I had thought that the high water use of California's Central Valley almond trees was something that was relatively widely known. I know I've encountered in in a variety of readings over the last couple of years, and I haven't been specifically trying to research it.

This is something that has already been written about a fair amount; is it really fair to expect him to "do his homework" for the counter to your claim when it's based on what is, to some, common knowledge? Moreover, the poster that you had already replied to above included two links to articles about the cost (in water) of growing various things. If you feel the need to "check the numbers", I think the burden might be on you to go find them.

I think it's important to note that while you can divide the volume of blue and grey water used to make a ton of almonds by the mass of one shelled almond, and get 1.1 gallons, you're ignoring kind of a lot of outputs of almond growing.

Almonds have to be grown in warm areas. Cannabis doesn't.

Almonds don’t kill owls.

No, they’re just destroying the North American honey bee population.

Study: Exposure to rodenticides in Northern Spotted and Barred Owls on remote forest lands in northwestern California: evidence of food web contamination

Citation: Gabriel, M. W., L. V. Diller, J. P. Dumbacher, G. M. Wengert, J. M. Higley, R. H. Poppenga, and S. Mendia. 2018. Avian Conservation and Ecology 13(1):2.

Link: https://doi.org/10.5751/ACE-01134-130102

DOI: 10.5751/ACE-01134-130102

Abstract: The documentation of anticoagulant rodenticides (AR) in nontarget species has centered around wildlife that inhabit urban or agricultural settings. However, recent studies in California have shown that AR use in remote forest settings has escalated and has exposed and killed forest carnivores. Anticoagulant rodenticides have been documented as physiological stressors for avian species. Northern Spotted Owl (Strix occidentalis caurina) critical and occupied habitat overlaps the areas where these studies occurred, yet no data were previously available to demonstrate whether this species was similarly affected. We investigated whether avian predators are also exposed to these specific pesticides and whether Barred Owls (Strix varia) may be a surrogate to indicate exposure rates in Northern Spotted Owls. We documented that 70% of Northern Spotted Owls and 40% of Barred Owls were exposed to one or more anticoagulant rodenticides. None of the rodent prey species sampled within the study area were positive for ARs. There were no spatial clusters for either low or high rates of exposure, though we detected low temporal trend early on throughout the study area. We hypothesize a recent change in land-use toward marijuana cultivation may have led to the increased use of AR in this area. This study demonstrates environmental contamination within occupied Northern Spotted Owl habitat and that Barred Owls can be used as adequate surrogates for detecting these pollutants in a rare species such as the Northern Spotted Owl. Furthermore, additional studies should focus on whether these pesticides are also affecting prey availability for these forest avian species.

As opposed to rat poison anywhere else? I don't see this as a failure of pot farming, but rather farming in general.

I think what the article is saying is that marijuana tends to be grown frequently in the feeding grounds of owls, more so than other non-marijuana crops. In addition, the unregulated nature of growing marijuana means the regulators can't track what's going on, or punish infringement. Overuse of poisons by mainstream farms is a problem, but a different one.

That said, I couldn't see any real data here. I don't know whether this is a bigger problem than people using rat poison in general, or putting slug pellets around their lettuces.

Based on your defensive response, I take it Californians eat/smoke produce grown with rat poison. Have you guys really thought about what you're doing? That doesn't seem very smart, at all. I've never seen rat poison in use on a farm around these parts. Always farm cats.

I'll be sure to check my labels more carefully at the grocery from now on. No more California produce for me.

What a poor sample size to base your judgment on. Also, it's pretty hard to avoid California grown produce.

> the state produces almost half of all the fruits, nuts and vegetables grown in the country, as well as a whopping share of the livestock and dairy. [1]

[1] http://beta.latimes.com/food/dailydish/la-dd-calcook-califor...

Do you eat uncooked meat? Wash your vegetables.

Pretty sure The Spotted Owl eats cats too.

"The study, published Thursday in the journal Avian Conservation and Ecology..." I tried to find the publication but their site only shows December and says that next issue is still in production. On another note, we use plastic tubing to keep rodents from chewing or "girdling" young trees and shrubs up here in Canada, it's the deer that really cause trouble.

It's time for robotic scarecrows!

Eventually, all farms will do away with pesticides and either keep out pests or kill them without chemicals. Swat them or catch them, just like the robotic exterminators that will live in the walls and floors of buildings. Maybe they'll even digest them for energy.

What about little pest-tracking laser turrets?

Good job it's legal then, that means it can be regulated.

If growers are willing to break the law to grow an illegal crop, what makes you think they won't break the law to bet better yields?

Plus, in the current political climate, it feels like regulations are being struck more frequently than they are being created. And the regulations that are left have nobody to enforce them.

I don't think the legal status of the crop makes much difference.

> If growers are willing to break the law to grow an illegal crop, what makes you think they won't break the law to bet better yields?

That's like expecting an illegal gambling den to follow OSHA laws on floor mats better than a casino in Vegas with service union employees.

Growing is highly illegal, and using illegal rat poison techniques is a tiny offence in relation to it. Whereas legally growing and illegally using rat poison is a large offence in relation to no offense at all.

Making it legal means that the illegal growers of today can be pushed out of the market by law-abiding growers.

The only reason that a rinky-dink illegal pot growing operation is lucrative today is that it's illegal and most people aren't willing to take the associated personal risks.

What I seem to be missing in this article is an explanation why marijuana farms apparently use so much rat poison in the first place.

My understanding is that the rats chew on the plants to get moisture, since the plants are so well irrigated compared to the relatively dry surroundings. Rats nibble on just about anything.

That's interesting, cause my impression was that warfarin causes vitamin K deficiency and makes animals very thirsty. Maybe the rat poison is actual making the rat problem worse...

okay so i looked into this: from what I can tell, warfarin poisoning doesn't cause dehydration directly, but it does cause severe diarrhea, vomiting and excess bleeding. From what I can tell, all of those things constitute fluid loss and would lead to dehydration.

maybe the pot growers should provide the rats with some water...

My dog loves hunting rats. Why don't they just get some dogs?

Rodenticide is probably cheaper. Dogs have to be fed, watered and cared for.

Or cats. That seems to be the age-old solution to the problem. Barn cats are wildly efficient vermin murder machines.

Some of the rats in NYC are quite big, I'm not sure cats would go for them.

Oh our old barn cat would come out of the barn door carrying a dead rat so large she couldn't hold it off the ground.

Yeah, my cat's literally dug up moles before. I know NYC has mutant rats, but I'm sure it's not difficult to find a cat adventurous enough.

I have seen a junivile cat do the same she was hardly out of kittenhood and took a rat bigger than her.

Yeah, at the right age, a juvenile cat is a pound and a half of death, and it isn't shy about showing you. I think later on in their lives cats are a bit more secretive, especially about prey they want to eat.

If you don't feed a cat much, it'll go after just about anything rodent-like that it thinks it can sink its teeth into.

[Edit: also bird-like, which is why a number of eco-friendly people aren't too fond of free range domestic cats in many different parts of the world]

Our old barncat just hunted the ratlings. Tenderer meat, you know.

You will need a lot of dogs. Rats can breed like crazy if they have enough food.

or some owls?

Should we tell him?

This type of story had been reported many times over the years. The only difference is the animal in the food chain in question. Something up the food chain is feeding on something humans want to eradicate. Horrible, yes, but unless they ban such things this will continue. The last time I heard of version of this was Falcon being killed by eating poisoned pigeons in urban areas.

Although some products are being phased out, they are still available despite widespread pressure from federal regulators, wildlife officials and environmentalists to remove them from store shelves.

So isn't this more of a regulatory issue than an issue with pot farms in particular? Don't farmers of other crops do the same, or is marijuana particularly susceptible to rats?

Why is rat poison being used as part of growing marijuana? It doesn’t strike me as an essential pesticide to defend marijuana with?

I’ve never heard of rodents being associated with marijuana destruction. Is marijuana one of those odd crops that attracts a different category of pests? Like flower bulbs and deer?

I don't get this story... Illegal grows have been going on for decades in these areas. If anything, there should be fewer now because of legalization right?

Weed should be totally organic man.

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