On my commute to and from work there is a field where I regularly counted a dozen or so deer last fall. But after the December rifle season I saw nothing – except maybe one or two once in a while.
So I knew spring was here because today at 7:30am – well after sunrise – I counted 16 deer feeding in that same field!
That means deer, especially females, are hungry. In a previous post, Danielle explained weight gain and loss in deer. Well, now it’s time to gain weight, and because pregnant females need to eat to feed their growing fetus (and most likely two of them!).
But my seasonal observations of deer activity got me thinking. Are my anecdotal observations of deer simply me accepting observations that I expect – and ignoring the observations (where I don’t see deer) that do not fit my perception of reality?
With this study I had an opportunity to test my theory with some real deer movement data. My question was “Do we see a decline in deer movements over the winter and then an increase when spring arrives?”
To answer my question, I took all 8,640 of our deer locations for 2015 and calculated a mean distance moved per day and averaged that over each week. I first did this for the northern study sites (Potter County).
Yup! You can clearly see that movements steadily decreased through January and February until mid-March. This week deer were traveling almost twice as far as 3 weeks ago.
I next wondered if maybe deer starting moving earlier on our southern study sites located just south of State College.
Nope. Not really. On both study areas deer movements bottomed out at about 800 yards per day three weeks ago. And now both groups of deer are traveling about 1,600-2,000 yards per day!
So forget Punxsutawney Phil – the deer will let you know when winter is over!
And I am once again amazed at how well deer can disappear. Just where did those 16 deer I saw in the field this morning hide for the past 4 months?
-Duane Diefenbach
Correction March 30, 2015
An earlier version of this article incorrectly calculated mean distance traveled per day (presented mean distance traveled every 7 hours). The corrected version also provides the mean distance per day in yards instead of meters.
Also, an earlier version of the article referred to deer increasing their metabolism this time of year. This is incorrect and deer simply are able to gain more energy than they expend so that they are able to gain weight and support developing fetuses.
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