Building Snake and Lizard Habitat and Winter Dens

I've noted elsewhere on the forum that garter snakes and alligator lizards have given me a slug free garden. Slugs abound in the forest that surrounds my garden. I believe that the snakes have made my largest, sunniest mound their home.

Garter snakes use large communal dens during the winter. They prefer well drained south facing slopes where rocks provide deep shelter well below the frost line. My property runs along the ridge, on the north side of the Nanaimo River. My slopes face south. This is already prime reptile habitat. I plan to improve it further. I have two areas that are really well drained on silty gravel, just above the ridge. These areas would be improved by the addition of some larger rocks. Using the excavator, I'd like to go down 10 ft. The holes could be filled by my abundant supply of rocks. Snakes and lizards both require warm basking areas where they go to heat up before going hunting. Alligator lizards are very sensitive to this requirement. They do well in clear cuts and often abandon areas where trees grow up to shade their basking rocks. I will grow grapes, herbs and other heat lovers near the dens and keep tall trees and bushes cut back.

I hope to make my place an attractive wintering site for all of our reptiles. None pose any danger to humans or livestock. These areas near the crest of the ridge are well outside of where I am putting roads or large buildings. The most secluded area will be designed to accommodate the very shy alligator lizards. Their need for hot basking areas is greater and since they flee whenever they see people or other large creatures, this will give them a better chance to feel safe. Lizards that are constantly disturbed don't feed as often, since they loose heat while hiding deep in their dens. Reproduction rates improve as the habitat improves. All of the species I'm looking to attract are abundant and not threatened. Still, I won't be handling them or bringing any reptiles. They are already here.

I may need to put some space between the snakes and lizards. Garter snakes will eat young lizards. The lizards favor the hot slopes. Garter snakes like the boggy areas and the stream.

The existing hugel beds will be improved with some dark rocks on the south side that adjoins the gravel road. The snakes already bask there. In the morning, when the rocks are still cool, the snakes bask on top of the leaf mulch. With its low thermal mass, it heats up early in the day. Snakes returning to bask in the afternoon are more likely to be found amongst the rocks. I've seen lizards on dark rocks that were too hot for me to sit on. After basking, the lizards are really quick. A deep layer of rock on the hugel's south slope, that holds heat through the night, will allow snakes to warm up earlier in the day and to stay warm into the evening. A snake who remains warm through the night, digests food faster and thus is able to feed more often. This improves growth rates and reproductive success.

Garter snakes are found as far north as Fort Smith in Canada's North West Territory. No other North American snake comes close to this latitude. Their ability to reproduce over a short season is key to their survival. Young are born live. The largest communal dens and the largest congregation of reptiles in the world are found in the southern lakes district of Manitoba Canada. Up to 70,000 red sided garter snakes congregate at the Narcisse Snake Pits, which are large limestone caverns that allow the snakes to go deep into the ground to avoid the harsh winter.

I'd like to have a few hundred snakes. At both ends of the denning season, garter snakes spend a few weeks near the den sites. This allows them to feed and breed (spring) close to the safety of a deep den. They retreat to the den during cold weather and at night, but they surface in the heat of the day. The warm micro climate of my south facing slopes would allow them to stretch their active season a little. Some of my tender fruits will require netting to keep birds of of them. Eagles, hawks, ravens and owls are snake predators. The netting will keep those areas safe. Predatory birds are known to follow snakes movements, so that they can locate others near dens. Some prime basking rocks will be given an overhead net.

Before going very far into this, I'm going to run my plan past some snake experts. My hugelkultur mounds have become great snake habitat. The big one in full sun is only about 150 ft from a cool wet area with some standing water. I suspect that the snakes that bask on the hugel bed are hunting over a wide area and returning when they need to warm up. The beds seem devoid of prey for so many snakes. Not one slug. None.
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All of Canada's reptiles are beneficial species that are legally protected. I will therefore not transport or otherwise interfere with these animals. Once established, denning areas will not be excavated again. Any alterations will happen in the summer after the snakes have dispersed. Excavator work on occupied hugel beds will be done in the warm season as well. When I added to the big one a couple weeks back, The snakes all headed for the forest as the machine approached. Usually machine work is preceded by chainsaw work and other activity that causes wildlife to retreat to a safe area. Two hours after 600 sq ft of new bed was given a top dressing of soil, a snake came to investigate. It may have been looking for bugs in the newly disturbed soil, or it may have been interested in the new real estate.

I read this with interest. We have tons of snakes and lizards here but I am planning to build a little condominium for them (pile of broken masonry rubble) near my container garden. I've noticed that the population of bug-eating skinks has exploded this year because it's been less dry and because I've added a lot of features to my garden area where they can hide and rehydrate. Except for a stink bug infestation on two plants, I've had zero bug trouble. Do skinks eat those big green tomato hornworms? Because something's eaten them all this year!

A sheet of plywood or sheet metal placed on top during the rainy season, can make the rubble pile more attractive. Early in the day, when rocks are still cold, lizards will warm up on top of plywood or under the metal. Reptiles often take risks of predation while they are sunning. A nice slab of black slate facing south, provides a nice hiding spot for morning warm up.

I found this in an old thread about garter snakes from 2009.

Brenda Groth said --- "Snakes love love love piles..piles of just about anything..they will nest in compost piles or piles of leaves, they will hide in piles of twigs and hunt the mice that live under them..and they will toast themselves in piles of hot rocks..they love hot rocks..any log is always great for snakes..but they even love a mixed pile of logs and sticks and leaves better.

The potatoes that were produced in the hot sunny hugelkultur, we're nearly all perfect. No bugs, slugs or worms.

This 14 ft tall mound, is in a more shady spot where it's too cool for snakes for most of the year. I've never seen an alligator lizard in cool shade like this. Most of the potatoes grown here, we're damaged by wire worms and snails. Four snails were munching on the one in my hand when I harvested.

Some of my trouble with this mound may be caused by other factors, but the soil and moisture here is totally suitable for potatoes. They grew well. I dug up 35 plants in the warmer location where the reptiles live. Not one snail, slug or wire worm was observed. I think it's safe to assume that both beds provide suitable habitat for the pests. The soil is the same and the same weeds grow. The big difference is shade, which makes it cooler and less attractive to my cold blooded friends.

I'm going to drop about 10 alder trees that shade the bed. I will also add some dark basking rocks to the south side. The snakes will probably find it on their own. With so many pests to eat, I'm betting that this mound will become another nesting area.

This thread is about my lizards. I thought they were alligator lizards, but after viewing more of them up close, I think they are western skinks.

https://permies.com/t/38853/hugelkultur/Lizards-hugelkultur-home

Edit--- two years later.

They were not Western skinks. They were juvenile alligator lizards. The juveniles are skinnier and look like skinks. We don't have skinks on Vancouver Island.

Hi Dale

I came over to this thread after reading about your slug-hungry snakes in another thread.  My garden is near you, on the sunshine coast, and I'm hoping that some slithery neighbours might be persuaded to move in.  I just am having trouble envisioning how to set up the rock pile etc.  Could you put up a diagram or pictures showing the lay of things where it's working to increase snake population?

I make piles of rocks, calling them check-dams, in the bottom of ravines. When I check on them,  I'm likely to find a sunning lizard.

One place I see lizards frequently is a boulder that is sitting exposed on the side of a hill, and it has cracked apart. The crack is about 1" wide at the surface, and is highly attractive to lizards.

We have a healthy lizard and snake population (despite two hunting cats) in our yard.

We've lined most garden beds with limestone dug out the ground (either when digging beds or when neighbors dug the foundation for a new house. These rocks are in very irregular shapes so they form tiny crevices and little caves everywhere they're used. The lizards seem very fond of the rocks. We've also had several toads dig burrows underneath some of the larger ones.

I don't know if the brush piles and thick wood mulches would be as good for your snake populations. I'm fairly sure that's why we have such good snake populations. Nearly ever snake I've seen has been slithering through the mulch. One of them I actually dug up with the garden fork from several feet deep in a chipped wood pile while I was filling a wheelbarrow. It was nearly three feet long with neon green stripes down it's length. For a moment I thought someone had left a green nylon rope in the chips. He was released unharmed by our compost bin.

Well here's the start of my rock pile. More to be added when I can source them.  

My garden is tiny -just 8 2x2 foot raised beds in a deer fence so far and now an adjacent little heap of rocks on the upside of a boulder.  It's a south facing slope with known garter snakes in the region so I'm hoping that some slithrry slug eaters will come visit.

Sorry for the late reply Genevieve. Snakes like to stay under cover much of the time. Although this rock pile may be attractive to them,  I suspect that having to crawl across open ground in view of hawks and other predators, could reduce the chances of them making it home. If there were some old stumps or other debris scattered in the direction of the nearest tall grass, this would give them a safe route to travel. Some snakes always want to be near water. Garter snakes are much more likely to visit if they are given water.

In a 2015 post earlier on this thread, I said that I thought I had Western skinks. They were juvenile alligator lizards. The variation in my lizard's seems to be just between male and female and different age groups. They are all alligator lizards.