Beaver Castor Mound Set: Easy And Effective

beaver building castor mound

A few seasons back a buddy of mine convinced to break out of my beaver trapping rut and start setting some castor mounds sets. I had heard the story before but I didn’t think my beaver harvests were lacking so I ignored him again.

But after going with him to check his out I was convinced to add the castor mound set to my beaver trapping set list.

Beaver Castor Mound

Beaver are very territorial and they use a castor mound to mark the area they live. They send a message to all passing beavers that this spot is spoken for and no new beaver are welcome.

A beaver creates a castor mound by gathering leaves, mud and other flotsam from the water and piling it up at the waters edge. After creating the mound they will leave secretions on the mound to mark it.

A castor mound can vary in size and the larger they are the longer a particular beaver has used it.

Difference Between Castor Mounds and Scent Mounds

A scent mound is not the same as a castor mound. It’s important to know the difference as a castor mound set will not work on a scent mound. Beaver use them in different ways.

The scent mound is built by the beaver in late winter to early spring in an attempt to attract a mate. It isn’t used the rest of the year.

Scent mounds are significantly smaller than a castor mound and you will usually find multiple scent mounds near each other, while castor mounds stand alone.

Beaver Castor Mound Trap Set

The castor mound set is so effective due to the way a beaver uses the mound.

When building or adding on to their castor mound, a beaver will dive into the water and get material from the bottom. Once they have a hold of some material they keep it in their front paws and swim back up to the castor mound.

As the beaver reaches the front of the castor mound they use their back legs to lunge forward into the shallows. They then use their tail for balance and leverage by pressing against the ground and walking the rest of the way up.

This is important because the beaver will not use their front legs to walk as they are using them to hold building material.

This means a castor mound set is placed to catch the back feet of the beaver as they approach their mound.

The first step for making an effective castor mound set is creating a trap bed. The bed should be made in a depression in the area where the beaver will place it’s hind legs as they are approaching the mound.

The depression trap bed is important. If you do not make a hole for the bed you will have a lot of misses.

When selecting a location for your trap bed you need to assess how steep the water bank is. If the approach to the castor mound is in shallow water you will put the bed further from the mound. If the approach is in deeper water the bed will be placed right near the castor mound approach.

This distance tends to be right around one foot but look closely to make sure you bed your trap the right distance from the mound.

Last, make sure to offset the trap bed to one side of the approach.

Trap To Use

In general you will want to use the biggest trap you can legally use in your state. There are a lot of differing opinions on the best size to use but I like to use a # 5. If you can go bigger go for it but this should be more than sufficient.

Once your trap is in place add some castor lure to the area. This will tell the beaver that a stranger has been around and he will come and cover that castor lure up.


That next season I set my first two castor mound sets and they were both quick and easy catches. While this is not my go to set for beaver, it is used every season to great success. Learn how to bed your trap well and you will likely have the same success.

Written by Fred

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