Small predator

The Pygmy and Masked Shrews are North America's smallest predators most often less than 3 inches in length and small enough to squeeze through holes down to about 1/4 inch.  That's basically this size of a pencil if you are wondering.  As you do for bears you must do for Shrews. No not a mini electric fence, but reduce entrances down so just a single bee can pass through.

Here in Minnesota we have two Shrews that can and will target beehives; the American Pygmy Shrew (Sorex hoyi), (see image 1), and the Masked Shrew (Sorex cinereus).  It hard to tell on from another by appearance. The Masked Shrew is slightly longer surpassing 3 inches including tail. However, that rule of thumb doesn't always hold true.  Accordingly, the teeth are the only real method of determining one from another. It's the unicuspid teeth in the upper tooth row that identifies one from another.  The American Pygmy has 3 and the Masked as four, (see image 2).  To us, it doesn't matter which Shrew has gain access, so I threw the identification is as extra credit that you can use at your next Trivia game.

Both the aforementioned Shrews are carnivores hunting down and eating such things as mice, insects, spiders, etc... Their metabolism is so fast that these smallest of predators are constantly eating and eating and eating some more. This constant need to eat is the overall danger to the wintering bee hive.

The damage inside. Come spring when most of us up here in the northern state evaluate winter losses is when we find evidence of an intruder such as a mouse or possibly a shrew. It's fairly easy to determine if a mouse caused the damage or if it was a shrew.  Mice will setup shop inside the hive by building a nest, destroying comb, pissing and pooping on the top bars.  The main difference between the two fecal matter is the size and the shape, (see images 3 and 4). The Shrew's dropping has an appearance of a cork screw, where the mice has tapered ends. When the Shrew invades the hive it will eat and eat and eat. If a mouse is found in the hive, the Shrew will eat it too.