Planned Parenthood for SQUIRRELS???


Yep, its true.

I first read about this on National Geographic’s site in the article, Squirrel Birth Control: To Stop Invasion, Science Gets Seedy. The subtitle is, Drug-laced sunflower seeds may lower numbers of the booming rodents.


I like squirrels and am one of the people feeding the little varmints, but not everybody is so squirrel friendly. The squirrels do a lot of damage and make a bad name for themselves getting into mischief with those sharp choppers.


Last year with the weather so mild in winter, the squirrels must have been getting busy in the trees. Did you know they have two litters a year with usually two to four kits? I saw two of them starting a family in my backyard late Spring. They are pairing now too, from December through January.

There was a bumper crop of little squirrel this past Spring and Summer. But really, nature was busy producing a bumper crop of nuts, so food was very plentiful as well. Plentiful supply leads to more squirrels.


What started South Carolina’s Clemson University to look into squirrel birth control, was that the little rodents were decimating fruit crops by eating and tarnishing fruit.

It got so bad that squirrels were eating half a tree’s fruit in a couple of hours. Some apples only had a bite or two, making the fruit worthless for commercial sale. Compounding the damage, they were girdling trees, and that can make any grower want to have war on the squirrels.


Once it hits cash crops, biologists spring into action. They had a decade-long struggle with the gnawing rodents, so something had to be done, and fast.

Various methods were tried. They looked at non-lethal squirrel-control methods, like capturing and then injecting them with birth control chemicals. This was labor intensive and very time-consuming.


Not to mention a little humorous. Can you just picture scientists racing around the tree filled lawns armed with tiny condoms and little contraceptive injections? So they resorted to a seedy solution, settling on a food delivery method. Knowing squirrels just love sunflower seeds gave them an idea.


The drug laced seed is created by researchers at South Carolina’s Clemson University, using a drug called DiazaCon. This drug, originally developed for humans but discontinued due to side effects, mimics cholesterol in the system and inhibits cholesterol production. This lessens reproduction. It did not start with squirrels though.


The drug made its way to limit reproduction on nuisance birds, like pigeons, blackbirds, starlings and sparrows, among others. It was marketed for pigeons, trademarked,  Ornithol. Then it was further tested on mammals, such as rats and prairie dogs.


Now the drug is being looked at for squirrel control by lacing sunflower seeds. Mixed in with the DiazaCon coating is a nontoxic dye that, once ingested, stains the squirrels’ undersides pink to identify treated squirrels from those untreated. They must be darn cute with their bellies dyed pink.


To read more on South Carolina’s squirrel problems on the AP site, check out their site. Also, Clemson Cooperative Extension has a web link too.

You really have to wonder what the squirrels would think if they were cognizant of what humans were up to. Really, when you think of all the animals, insects and plants we mess with and much for the sake of our well-being, it really does not shine well on us as a species.

The birds I mentioned taking this drug… some of them developed muscle tremors. Is it worth destroying the lives of other species? Honestly, looking at all the cute squirrel photos in this post, it is hard to imagine them being so destructive, yet they are. So what is the answer?


I wanted more info on squirrel population explosion and went to Science for some intellectual insight on the subject. I found an article that talked about the surplus of seed and nuts in relationship to the subsequent increase in squirrels reproduction.

I am somewhat knowledgeable reading these papers and have to admit the one I was reading was overkill. They used phrases like, “resource pulses”, calling squirrels “seed predators”, seed production was “seed masting”, more squirrels, “trophic levels of ecological communities”.

Hey, all I wanted to know was the statistics of additional squirrels last year and of course that was not noted. Sometimes, it is better to just say it like it is. Just call the gray squirrel black, when it is indeed black!


About Garden Walk Garden Talk

I love to photograph, paint, draw, design, garden, travel the world, and pass on a few tips and ideas that I learned through experience as a Master Gardener and architect. I am highly trained in my field and enjoy my work each and every day. I garden in Niagara Falls, NY in zone 6-B. Find me at:
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59 Responses to Planned Parenthood for SQUIRRELS???

  1. terryshirkie says:

    dear are such a gentle soul..i just don’t understand how you can get so close to god’s creatures and take such superb pictures of them.!…..and they are not afraid!
    i really like the photo of the black squirrel…although we have many greys and browns on this east side of town, we rarely have a black… when i pick up my kids for sunday school on the west side of town, i will see many black little animals…i have to go by a park and so i guess that is where they live…they have had a lot of good sunny and warm weather so far this autumn and the little guys are still running around looking for food!
    i am glad that the american scientists aren’t killing them but are trying to solve the problem of over reproducing!…it is against the law here in welland to shoot the squirrels donna.
    i have to go now but i will be back to tell you a real neat squirrel story that i remember….maybe a few, eh?……have a great day my new american blog friend…love terry

    • Thank you Terry, you are so kind. I have telephoto zoom lenses, a 300mm and a 400mm. But I do get close on occasion. I was at the Falls yesterday and was feeding a couple of squirrels that approached my truck in the parking lot. I was just at the feed store and purchased a lot of seed, so since they were begging… I threw out some critter food. I placed it at the front bumper of my parked Jeep so no other car would run them over. I bent down and actually petted the tail of one squirrel while it was feeding. He just kept on feeding. I know they bite so I was careful. I was bitten by an injured squirrel I tried to save a few years ago. I had on welding gloves and he bit right through them, so I know first hand those teeth are sharp.He did not live as he had a broken back. I was hoping the paralysis was temporary from shock, but sadly, it was not.

      Terry, add your link to the post. No one can get back to you.

  2. Interesting. Like any over population in nature it is due to a lack of predators. We have gotten rid of lots their predators either by habitat destruction or outright killing them because people don’t like to have coyotes, foxes, opossums and raccoons where they live. Tainting seeds concerns me because birds will be eating them too. Will this make the birds sterile also? I at least hope that they engineered these seeds so that it is selective. My daughter is graduating from Clemson University next week with a horticulture degree. Great photos of your squirrels! I have a small population in my garden. I see their nests high up in my trees and they get the scraps the birds knock off the feeders (I have squirrel guards on my feeders) and all the seeds and berries they can find in the woodland garden. They often eat my strawberries but I share.

    • My thoughts exactly. Even when we introduce predators back into the environment we screw that up too. I just was reading a paper on reintroduced wolves. There was a radio-collared alpha female that was just shot out in Yellowstone. Why I think this is a crime is that the pack now will be in anxious confusion. They believe the young pack will splinter and become aggressive to one another. Hunting season is opened for shooting wolves during a limited time of the year. Now why do they do that. Raise them, collar them and open season on them? I know the scientists are saddened by this and they have no control where the wolves roam, but again, why allow them to be killed. Farmers kill them as well. Plus, many do not want the wolves in Yellowstone, so that leaves the questions open on what to do?

      • Thanks for the links Donna! They were interesting reads, especially the comments. I think wolves are such gorgeous creatures. You are right this is a very complex issue. I just often think that our interfering with Mother Nature seems to knock the balance out of whack. Wolves would certainly help keep the deer population in check. Knowledge is power and I just wish people would learn about animals in their area so they understand them. Reading about the wolf hunters was sad. They seem like they have really big egos and like their bragging rights. Makes the kill even that much harder to swallow. You would think it would be illegal to kill an animal that is tagged. There are birds that are better protected than these wolves.

        • I was very saddened by the wolf story and agree those hunters are very overt in their desire to kill and show off the mount. I could show images on my blog that would make you cry of big game in Africa. I had an opportunity to go on one of these hunts to be the photographer, but I could not do it. I could not stand to see the life leave a magestic animal like that. And it is not like you eat the meat of an elephant, giraffe or lion. And what most don’t know is animals like wild bore are shot for fun. Then they use some as bait for the bigger game. Plus, some of these parks are fenced and an animal is let out of a cage (like leopards) and shot instantly. The kill is guaranteed. So what sport is in that?

  3. Count me among the squirrel lovers, though I leave them to forage for their own meals. Any animal damage that reduces cash crops is cause for concern … and it’s good that science is looking at non-lethal means to help limit the damage. It’s tough, though, because we put a huge, appealing food source out there (meant to be OUR food) but the squirrels (and birds and rabbits and deer) don’t get the message. It’s the same here, with a large area of tasty roses to add variety to varmint diets. I just think of it as sharing, and i get on with life … agriculture can’t really do this, tho.

    • I used to not feed the squirrels, and the feeders are pretty resistant to them climbing up on them, but the squirrels just wait for the sparrows to throw the seed out to ground feed. Then I started feeding them critter food and that has worked out much better. They like it more and the birds are happier as well. I know, like you said, we entice them with our food crops, but these are the same farmers shooting coyotes. I did not realize that the mammals were eating the rose hips. I have seen birds on mine, but never squirrels. The thorns must keep them off. I do feel for you raising roses though. It must be frustrating to have damage. I don’t mind sharing either. I have been getting rabbits and so far, I out plant what they take.

  4. Very interesting post and the links were a good read as well. I agree with one of the previous comments that this is what happens when you get rid of predators. When you eliminate coyotes, foxes, snakes, hawks, and the other critters that snack on squirrels, you naturally get an increase in the squirrel population. It’s just unfortunate that in our human logic it makes more sense to sprinkle birth control laced sunflower seeds throughout town (with who knows what side effects and impact on other species) than look at habitat loss, housing encroachment and the other issues that remove the higher level predators from the environment. Thanks again for the food for thought.

    • I have snakes in my yard!!! Garter snakes, but they are pretty good at keeping the slug population in check. No mice either. Hawks are common here too, and I saw a hawk/squirrel battle a couple of years ago in my pear tree. A Red Tailed hawk attacked my favorite squirrel, Gilbert. Gilbert was really bloodied, but did live. He would not have had I not run outside. He had claw marks on his back and a beak gash in his neck. I was just in time.

      There is no logic in the seed dispersal method. They already noted some species of birds getting muscle tremors from the drug. It all depends on the timing of their reproductive cycle and some birds could not have the treatment, so when you put out treated seed, it is inevitable that the wrong species will consume it.

      I write on environmental issues quite a bit. The answer to almost all the problems noted is us. Too many of us.

  5. lucindalines says:

    Put some feral cats in the orchards. My neighbors have squirrels, I don’t. They may be cute, but remember they are still rats with fluffy tails.

    • We have a number of feral cats here in the city. I have seen confrontations between the cats and squirrels and the squirrels have always won. I know cats are superb predators, but never saw one take a squirrel. They have a lot of places to stalk from in my yard too, but are always unsuccessful. My dog on the other hand, has caught squirrels. The one I tried to save that I mentioned in a previous comment, was caught by my Akita.

  6. We are always so eager to reach for a chemical, and many times there are unintended results. I know I have mentioned before that my cats catch squirrels and keep the population under control. Why not employ cats in orchards? We also kept squirrels off our feeders by sprinkling corn on the ground for them to eat.

    • I think the problem with cats in an orchard is like what I see at the tree farm. All the trees are lined up for acres, just like the fruit trees, and there is no place from which the cats can stalk. It is too wide open. Weeds have to be controlled and this is where a cat would hide from sight. The rows are hit by the weed hog and tilled under, or in the case of fruit crops, herbicides are employed. Plus in a tree orchard, the squirrels jump from tree to tree and the cats are not quite as nimble as a squirrel. The feral cats here are not as lucky at catching squirrels. In my yard there is a lot of cover for the cats, but not enough room for cats to gain the speed necessary to chase them.

      • Emily Heath says:

        What’s the issue with weeds in an orchard, would they affect the crop? Monocrops like these are bad for bees and other wildlife. I don’t see the harm in letting a few flowers spring up between the trees.

        There have always been squirrels about, so I wonder how farmers in the past managed. Were they more willing to accept the losses, as there was no other option available to them?

        • There is a very good reason for the control of weeds. It is for control of girdling the trees by mice, voles, gophers, rabbits and squirrels. Also, weed removal allows the fertilizers to reach the trees and not the weeds. I know I like the wildflowers very much, but in a production field, they are competition, and cover for those gnawing animals. In winter, the mice are bad and dried weeds allow blowing snow to build up around the base of the small caliper trees and mice benefit with a warm spot to gnaw away. Weeds out of control (tall and numerous) also benefit deer and everyone knows what deer do to trees.

          I think if you look back in history to very early farmers in this country, farms had more predators roaming about. Also there was more forests where it was better for wildlife to live. Squirrels without natural predators, adapted to our way of life and we pay the consequence. I still like them and have no problem sharing my yard with them. They live in the 90 foot high Norway Maples on our street.

          • Oh, I forgot to add,… the digger bees use the fruit trees early in the season, so bees do benefit from these crops if they are NOT sprayed. I see digger bees at the tree farm where the fruit trees are non producing and not sprayed. But I do agree about the monoculture of any cash crop.Unavoidable I think too, since the food production is for us!

  7. My first reaction was: give those scientists a Nobel prize! I don’t hate squirrels, but I do find them annoying. Then the thought of the birds eating the seeds gave me pause. I agree with Karin that more predators would be the ideal solution, but people freak out about many predators, too. I do think it is reasonable to try to control the squirrel population, since people have fueled the growth in the number of squirrels.

    • The problem with predators is really a complex issue. Most need a wide expanse of territory, and where can that be in such a heavily populated country. You get black bears in people back yards and swimming pools. Even places like Yellowstone is not large enough for them not to come into conflict with humans. Not to mention how stupid people can be when in their habitats. I never feel too sorry for those suffering at the paws of a bear when they stupidly do not follow the instructions they are given before entering bear country. People go within a 100 yards of a bear feeding to grab a photo, and wonder why they end up attacked. And the campers leaving food out. Yipes! When young, I have had three encounters with wildlife that could have ended up badly for me, so I am more conscious of being careful and wilderness aware.

      At least squirrels don’t usually attack!!! But I did get bit by one once (not one of the three encounters).

  8. kellycat2552 says:

    They are cute though

  9. alesiablogs says:

    My grandmother had a pet squirrel in the late 60’s while I was growing up. The little fella just came right up to her and she fed him. I don’t blame the fella. My grandma was the best cook ever!
    Love the photos!

  10. Great photos! We only have gray squirrels around here.

    • We have mostly black squirrels here in my part of the city. The ones I saw starting the family was a gray and a black. Black squirrels are gray squirrels having more melanin concentrated in their hairs, and are melanistic variety of the Eastern Gray Squirrel. So really all the squirrels are gray. The red ones are at the Falls. I am not sure why they are so orange looking, but that is their natural color.

  11. This needs to be one of the craziest ideas I’ve ever heard ! What ever happened to squirrel stew? I’m sure plenty of rednecks still enjoy a tasty squirrel.

  12. I have seen what can happen when predators are reduced and squirrel populations get out of control…lots of damage. At this house now we have fewer squirrels due to more predators and fewer nuts in the area. This birth control idea is just NUTS (sorry for the pun)….really we need to stop playing with nature.

    • I am not sure about what constitutes out of control unless it is like the article I read where a tree is stripped of half its fruit in two hours. Here on my street is an army of squirrels. I can have more than a dozen in my small backyard all day long. They have never entered any attics, chewed wires that I am aware, or girdled trees. Rabbits did that here to a Japanese Maple. I have a Black Walnut behind my property too, so they have quite a lot of food sources. They do get into trash bags of neighbors that don’t can the trash. That makes a mess. No predator here gets them, but cars squish quite a few though. It leaves food for the crows and cats. I think we play with nature far too much.

  13. terryshirkie says:

    dear donna…i had planned a different comment but i can do that tomorrow..
    as my husband and i were reading your friends comments and came to yours about gilbert, my heart was hurting…that is way too i am not blaming akita because that is just nature, but it really makes me irate when people abuse god’s creatures for no reason at all!
    it is illegal in welland for people to shoot the squirrels but more often than not, parents buy their kids bb guns and they shoot the squirrels and the birds….i think that bb guns should be illegal!
    it is too bad that those little monsters are destroying the apples donna!…hahahaha…i think that the american scientists are on the right track…at least they aren’t slaughtering them like they were in texas with the foxes.
    i used to have a favourite uncle, but there came a day when i was a teenager that he became not my favourite uncle ….he had a couple of cherry trees and one day when we went to see him, there was a very large pile of dead robins…i said. “uncle ray what happened to these poor little birds?”…”well, he said, “they were eating my cherries and so i shot them.”…i don’t think i ever really forgave him for this!….and no more was he my favourite uncle!

    donna did you ever read..”
    Wild Animals I Have Known by Ernest Thompson Seton

    your little story of gilbert reminded me of this book which i read as a child….i checked out google and found that you could read this book online for free….it is stories about hero animals like gilbert who most of them met with a tragic is a really sad book…the first story is about a wolf….it affected me too much when i was a child and so i don’t think that i could read it again but maybe you would be interested donna..

    donna, i don’t know how to put my link in, so i will try this, ok?

    i am with blogspot and so maybe that is why it isn’t showing….

    take care my friend and i will come back tomorrow, hopefully with those squirrel stories!…i love your blog so much! terry

    • Thank Terry for adding the link. I will check out the book. I enjoy reading about hero animals, but am saddened when they do not survive their heroics.I too would have been devastated to see all the dead robins. At the farm, they shoot crows and that makes me ill.

  14. Oh my, that is hard to believe. I hope the seed doesn’t somehow contaminate the groundwater or the soil in some way and affect humans, too. (Plus the damage to the animals as you mention.) I can’t help but admire the squirrels. I know they often cause problems, but they are truly a hardy lot. They are very fat and healthy this year. I’m wondering if we will have a colder/snowier winter than recently predicted.

    • You made a good point on the groundwater. I do believe it is a monitored program though. If it becomes commercial and for homeowner use, I think it will be of more concern on all fronts. The weather here is warm lately. We had some snow, but not much for this time of year.

  15. A.M.B. says:

    Ha! I will admit that I’m no fan of squirrels, especially the ones who aren’t baffled by the “squirrels baffles” on our bird feeders. Giving them birth control worries me for environmental reasons, but their population growth is worrisome, too.

  16. supernova says:

    mmm…Not sure about this idea at all. Sounds very risky and indiscriminate not to mention the moral aspects of a program like this. In instances like these, we’ve interfered and tried to control nature for many years now and at best we tend to always upset the balance in a detrimental way somehow. I do realise that a population explosion of one species may be bad for several others but ‘live and let live’ I think, as we don’t know what future consequencies may occur which might affect a species, nature will have its own voice! Great post, Donna. SN

    • Thank you for your wise comment. I find that often the ramifications are not considered. The studies are often funded with specific purpose and that is to the detriment of other species. This drug was developed for people, but seeing that was not going to fair well, it was tried on birds. Certainly, don’t waste all that research time, intellect and money!!!! Not working well on all species of birds, time to see if squirrels can be treated. To be fair, I do not know if they made modifications to the drug when it went into testing in different species. That would be interesting to find out.

      • supernova says:

        Your right Donna, studies are blinded too much on the effects to one given species, not to the bigger picture. It would indeed be interesting to see what research was conducted to transform this drug from being once suitable for humans (which was removed due to adverse side affects) then to birds and now suddenly being suitable for squirrels? Wildlife must not suffer any side affects then, eh? I agree, I think we may be speaking of recouping some money here! Cheers Donna and take care, SN.

  17. HolleyGarden says:

    This really bothers me. What right do we have to introduce drugs that may possibly change an entire species? Do we know the long term effects of this drug on squirrels, or generations of squirrels? I don’t think so. We seem to overlook the fact that so many chemicals have side effects that don’t show up for quite some time.

    • I too see this as a mistake. When I researched it further and found the drug being passed from species to species, I was very suspicious what would happen long term. What happens to baby squirrels that are born to parents on birth control? I would imagine this could happen.

  18. gardenbug says:

    I was told by my French aunt that in France they had made this illegal years and years ago. She implied that it was because children could be exposed to it somehow….She also mentioned a similar program for pigeons, also discontinued.

  19. Dear Donna, Who couldn’t love squirrels after seeing your wonderful photographs? We just have gray squirrels — haven’t seen a red one for years — and they are not as destructive as red ones. Totally disagree with using chemicals — we feed them, too. P. x

  20. Outstanding photos, Donna. So super SHARP! I could count the hairs on each squirrel (were I inclined to do so).

  21. Fossillady says:

    Oh, they are so cute, did you take the photos? Great captures! The presence of cats keep squirrels at a distance in my yard. I have rigged a bird feeder so they can’t get much from it so I’m back to liking them again! It’s so sad that these drugs create muscle tremors. I hope they can come up with an more humane solution.

    • Yes, all the photos on my site are mine, unless I note otherwise. Cats here do not ward off the squirrels. The people in my neighborhood feed the feral cats, so they are not quite as hungry to ambush squirrels. They never catch them.

      The scientists have not tested the seed on squirrels until pretty recently, so I am guessing they do not have a wide enough study that spans a long enough time to document the side effects, like they did with birds. But what I read, it all depends on how a creature cycles and when the drug is administered for the muscle tremor side effect to impact the animal. They do not expect that with the squirrels.

  22. b-a-g says:

    When I read the first section, I thought this post was going to be about natural birth control substances in sunflower seeds – I guess that was too good to be true. Brilliant photos.

  23. nicole says:

    What the heck! This is the craziest thing I have heard in a long time! Ha! Thanks for the chuckle. I need some of that for my yard. We have a crazy squirrel population here. The darn things come right up to my back door!

  24. paulinemulligan says:

    What an interesting article and certainly food for thought! Over here in the UK grey squirrels are a pest too, they were imported from the USA many years ago and are now killing off the resident red quirrels that we have. Killing them off because they carry a virus which they are imune to but once the reds are affected they die. They also take over the reds territory by being able to eat their natural food before it is ripe, so non left for the reds. Up in the NE of the country peanuts laced with contraceptives are being fed to the greys, in feeders which only operate with the weight of a grey squirrel. Reds are only half the weight therefore the feeder won’t open and also birds can’t get at the seed. There are still a few areas where red squirrels are hanging on and in these areas everything is being done to get reid of the greys, all this because some idiot imported some greys a hundred odd years ago, man has a lot to answer for!! We have greys in the garden here and yes, we do enjoy seeing them jumping from tree to tree but would much rather it was our native reds entertaining us
    Stumbled across your blog, will be back again, such interesting articles!

    • I have read about the red squirrels. That is ashamed the greys are doing such damage to the population. I was wondering how they are killing the reds though? Oh, you need to leave a link. I do not know your blog.

  25. thequeenofseaford says:

    Hi Donna, your comment on scientists running around with tiny condoms is pretty funny. Harming the bird population isn’t the answer to population control of squirrels. Some of the same thoughts were put forward a while back for the over population of deer. They are certainly larger and easier to inject with birth control. (beats those tiny condoms). Lovely pictures of the different squirrels.

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