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Saturday, April 14, 2012

A small visitor

When reaching for some seed to feed the birds at a friend's house in Salmon Creek, I noticed a small visitor in the bottom of the storage container.

Here's a close-up.

I think it's a Deer Mouse (Peromyscus maniculatus) — but correct me if I'm wrong!

I was curious about their noticeably long whiskers, or vibrissae, and how they might be used.  Unfortunately, I couldn't find much information about mouse vibrissae.  

So instead I searched for information about feeding in Deer Mice (How much bird seed had the mouse eaten?  Or in this case, perhaps it should be called "mammal seed" rather than bird seed?).

It turns out that a study was published about the effects of extra food on small rodent populations such as Deer Mice (Taitt 1981).  When given supplemental food, the mice decreased the sizes of their home ranges.  They were also able to reproduce even in poor weather conditions (e.g., the extra food allowed them to override the effects of cold temperatures that normally would have delayed breeding).  The author of this study suggested that Deer Mouse populations may be limited by seasonal food availability. 

This was just one mouse and a brief adventure in a bird seed container.  I don't think it will change the Deer Mouse population in Salmon Creek, but it probably made for a satisfied mouse!


1 comment:

Claudia said...

Our challenging Peromyscus! To identify to species, the main things you want to look for are: overall size, the relative size of the ears, and relative length of the tail, the amount of hair on the tail, and the how strongly "bicolored" the tail is.

But it looks like only two mice could occur on the coast in our areas: P. maniculatus and P. truei. These species can be easily distinguished by ear size. In P. maniculatus, the ears are usually shorter than the hind foot. In truei, they are about the same size or longer than the hind foot.

This fellow looks like a juvenile since the coat is greyer and the distinction between the back and belly color isn't clearly defined. It's a bit hard to tell from the photo, but it looks like the ears are smaller than the hind foot. So, yes a P. maniculatus.