Are There Bears in New Brunswick?

The answer to this question is “maybe”. There are wild black bears in New Brunswick, but there are no data on the relative population densities of these species.

Maybe you’re thinking “there has to be a way to figure out how many bears there are” and you’re right. We can estimate how many black bears there are by looking at the number of sightings reported to the government by citizens. This is called an index-based survey. The problem with this method is that it relies exclusively on people’s willingness and patience to report what they see, and we know that not every sighting gets reported.

So let’s look at an alternative. We can catch bears, tag them and then track their movements to see how many bears are around. This is called a census-based survey. The problem with this method is that it relies on people providing the government with a scientifically sound estimate of the number of bears in the area at a single time point (eg year specific counts), and we know that not every bear gets counted accurately!

It turns out that both approaches have their pitfalls, depending on what you’re trying to learn about: so we do some wiggling and then try to figure out what information we can gather about black bear distribution in New Brunswick from these two sources of data.

Let’s take a look at the data in the most recent government report to see if we can figure out how many black bears there are in NB by looking at a map of reported black bear sightings :

Why is the data in black? In order to understand the data, you really have to look at the map. The numbers along the east side of the map represent nine year long surveys that have been performed in New Brunswick since 1973 (with a couple of gaps). The numbers across the southern half of NB are seven year long surveys conducted between 1998 and 2006.

The first thing to know about these maps (and most other maps) is that they represent a sample, not an actual population. There are too many variables involved for a simple one wherever-you-look map like this that doesn’t account for all of them (like moving bears!).

If we look at the three dark green dots that fall in a band across New Brunswick (there are two small ones and a big one), it looks like they might be approximately equal in size. But if you look closely, you’ll see that the data for each bin is just not enough to make an informed guess about the distribution of these large black bears.

So there’s some serious data munging that needs to be done in order to make sense of this data (and bear with me for a minute, because I’m going to introduce another map that is even more confusing).

Okay, we can’t see the real sizes of the dark green dots, but at least now we know that there are nine long-term surveys and seven short-term surveys in New Brunswick (which means I get to argue about which method is better this time around).

If you look at the black dot on the far west side of New Brunswick, you’ll notice that it’s much bigger than any of the other five dots.

Are there bears in New Brunswick?
Okay, so now we can start to answer the bigger question: how many bears are there in New Brunswick? The short answer is that there are lots of small black bears and some very large black bears.

The long answer is a little more complicated. Next time around, I’m going to let you in on why it’s hard to count NB’s black bears and give you a sneak peek at where they might live!

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Author: newbrunswick

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