White-tailed Deer Hide and Seek

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- Hi, Sanford Smith here with Penn State Extension.

Today I'm joined again by Duane Diefenbach who is a wildlife biologist and the director of the Pennsylvania Cooperative Fish and Wildlife Research Unit with USGS.

And Duane is going to talk to us a little bit more about his research with deer and forests.

And today we're specifically going to focus on the movement of deer, especially during hunting season because many people have ideas where deer go during hunting season, but Duane actually knows the facts.

Duane, you've got a lot of deer that are collared so you know where they go during hunting season and you know where they go at other times of the year.

Can you tell us a little bit about that?

- Yes. So we have radio collared deer with GPS collars, so they're very accurate locations.

And these collars can get locations as little as 10 or 20 minutes apart, and they will collect locations throughout the day, 24 hours a day, 365 days a year.

And we have used these to monitor deer a little more intensively during the hunting season to see how they respond to hunting activity.

The conventional wisdom in Pennsylvania and many places is that on public lands there's lots of hunting access, lots of people hunting and so there are, as a result, fewer deer overall.

But what we found is on these public lands there are areas where deer can basically hide.

They discover areas that are unlikely to be disturbed.

And as a result in this current study, we've seen some of the lowest harvest rates we've ever observed in Pennsylvania, as low as maybe 25% of the adult bucks are harvested.

Whereas in most places in Pennsylvania it's 50 or 60%.

- Now these are mostly in forested areas where your research occurs.

- These are on large tracks of state forest land.

- State forest land.

So Duane, I've seen some of that work and you've shared it with me and we can show you some of the footage that's generated from these collars in terms of how the deer are moving on the land.

And one of the things I see is sometimes they go up on the side of a cliff or on a mountaintop or something where they're hidden in the brush sort of right off the edge of the cliff even where people don't go at all.

Can you tell us more about that?

- [Duane] Yeah, so I think some deer get lucky.

They discover a place where they're unlikely to be disturbed during the hunting season.

And what we observe is that, you know, by five o'clock in the morning they sense the activity that's beginning with hunters entering the woods and that's where they head to and generally lay down for three or four hours until middle of the day or middle of the afternoon while they get up and start moving again.

And those deer are just able to avoid being harvested by hunters.

And I think it seems sort of counterintuitive that public land that's has access to everyone results in actually lower harvest rates than on private lands.

But I think that it's such large areas, we have steep areas, areas with thick underbrush, that it provides lots of opportunities for deer to find places where they won't get disturbed.

- [Sanford] Yeah, Duane common sense tells a lot of people that the deer have gone nocturnal, that they're no longer around in the day.

Does that make any sense with your research?

- [Duane] To some extent, you know, that time of year is the shortest day length, but deer are still most active in the morning and evening.

But I think what we've observed is that that activity really drops off from let's say 5:00 AM to 10:00 AM in the morning.

But then by the afternoon and late afternoon those deer start moving again.

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- [Sanford] Oh, you have also discovered a few things or observed a few things that happened in the springtime at the time the fawns are being born.

Can you talk about that?

- Sure. Especially females, you know, they're going to seek out places to give birth.

Generally in May, April and May those family groups tend to break up and females will go off by themselves and find a place to give birth.

We've observed on some of our state forest lands that deer will actually leave the state forest to find agricultural lands to give birth to their young and they'll do this year after year.

Deer and most animals, if they find a place to successfully raise young, they'll return to that same area the next year.

And we've had quite a few different deer exhibit that type of behavior.

- Right. So the doe goes back to where she had success the year before or for the last few years.

- Yep.

- Yeah. Fascinating.

What about occasionally some deer traveling long distances?

Do deer, I don't want to say migrate, but do they go on journeys sometimes?

- [Duane] For the most part, no.

Most deer, once they've established their adult home range that's where they'll stay.

There are, well deer do disperse right?

So young, when they're about a year old will disperse from where they were born, maybe 10 to 20% of females, up to 80% more of males will disperse.

But there are always exceptions and there are females that will, or males that just make unexplained movements that with this new technology that we have with GPS collars we're able to see some of these interesting behaviors that quite honestly, I can't explain why they do it.

- Yeah.

- But it does occur.

But I think as a general rule, once a deer has dispersed from its home range where it was born and establishes adult home range, that's where it stays.

- Yeah. Okay. Interesting.

Have you learned anything about the the size of that range for a doe versus a buck or anything like that?

You know, is it 50 acres or a hundred acres?

Do you have a sense of that?

- Yeah, it actually varies depending on the landscape.

So in our state forests which are large tracks of contiguous forest, a home range of a deer might be, averages about a square mile for both males and females, except during the breeding season.

And that's when males home ranges expand because they are seeking out females for mating opportunities and their home ranges will increase two to four times.

So, you know, in our large tracks of contiguous forest in Pennsylvania, during the breeding season an adult male could have a home range of four square miles.

- Yeah, that's fascinating.

So a square mile is about 640 acres and if that buck is going over several square miles, that's a huge area that they're covering.

Well these have been fascinating things to learn about the movement of white-tailed deer, especially during honey season, but at other times of the year too.

And I thank you Duane, for joining me today.

- Yeah, thank you.

- Okay.