I teach an introductory course on mammal identification and natural history. This blog serves as a place for all of those stories, photos, facts and fun stuff that simply won't fit in the course. Type in your email below to follow this blog!
Beautiful view while waiting
at a bear den
(Almond, NY 3/13)
Last week we visited two more dens to round out our 2013 season. As I mentioned in my previous posts, my students take on the role of undergraduate researchers at these dens. We have a long term project gathering den data and when there are cubs present, we take the lead in gathering data for the NYS DEC to help age them. These two dens were fantastic successes in every way but could not have been more different. Fair warning: This turned out to be a long post :)
DEN #5: We found ourselves back in Region 9 (read: looong drive for us) last Thursday morning for one of the oddest dens I have ever seen. I was told the den would be on a Christmas tree farm, in a brush pile. Now, a brush pile is a very common den location in our area so that in itself was not surprising. What was unusual was the size of the brush pile! If my memory serves, we measured it at about 60 feet by 20 feet and ten feet high. The trick was for the biologist to hone in on EXACTLY where the bear was within this massive pile of uprooted evergreens. That work was done a few days before and it was determined the female only had a single entrance (and therefore exit) to the den. That would increase the chances that the female would remain in the den after being darted. We were allowed to within about a 100 yards of the den to wait while the advance team made their way in.
Bear den in the center of this massive brush pile
(Almond, NY 3/13)
Take a good look at this massive pile. These are all uprooted Christmas trees and certainly make a great fortress of solitude. Below is a somewhat closer look:
That is Jeb there are on the right and Art up top at the specific den location.
Everything went well and we were waved in promptly. There were three cubs at this den and once they were handed down from the den, we set to work taking our measurements.
NYS DEC Region 9 staffers
As I have stated before, the cubs get sexed and weighed. We then measure both hair length and ear length in order to determine cub age based on research done at the University of Virginia. Finally, each cub receives a PIT tag implanted just under their already thick hide between the shoulder blades. During this process, all cubs stay warm in their fleece bags (except for a brief check for gender) and on a cold day like this, the fleece bag often goes under the coat of the person holding the cub. Cubs are never handled with our bare hands (ironically) and no one cuddles, snuggles or otherwise treats them as pets. My students are here as part of their formal education in a transition from amateur to professional and they look and act the part. I am extremely proud of them and can no longer go to a den visit without running into several of my former students working for the State or are present in some other professional capacity. At this den, there were three FLCC alums.
FLCC students gather den data
In order to get everything done in a short time, the duties are divided among the group. So concurrent to the cub data collection, another group of FLCC students is taking den characteristic data. This was a project conceived of by the DEC staff in order to better understand this important aspect of bear behavior. Work has been done in other locations regarding den site selection and characteristics, but that information does not translate well to other areas of the country. Even information from within New York State is not applicable to us as we have a completely different environment here than say the Adirondack Mountains to our north. I am proud to say we now have data from about three dozen dens over several years and are ready to report on our findings. But that is another story all together...
Meanwhile, a third group is working with the adult female. Often the radio collar is changed or removed (depending on the research question and other factors) and the bear must be constantly monitored while she is chemically immobilized. Here, Wildlife Biologist Art Kirsch acts as note taker.
Data collection is an important job
Checking the CRT on a black bear
In this particular instance, the adult could not be easily removed from the den, so a single person entered the den to monitor her health. Dr. Jeff Wyatt, a veterinarian with the Seneca Park Zoo was on hand to take TPRs (temperature, pulse and respiration). Basically, he is looking for any change in these numbers. A drop in temperature may lead to the bear being covered in a "space blanket" to retain heat (conversely. if we were working in the summer we may have ice packs on hand in case the bear overheats -- no danger of that in THIS day). Pulse can be taken directly in the traditional manner or indirectly by looking at something called "capillary refill time" (CRT). In this case, the vet pushes his finger against the gums of the bear. This causes the tissue to turn white as the capillaries are emptied in the process. Then the finger is removed and the observer counts how long it takes for the color to return. In essence, this is a way to measure the pulse of the animal as the faster the color returns, the harder the heart is pumping the blood. Make sense? As with the temperature or respiration, the thing to look for is a change. If the pulse drops, that may indicate an adverse reaction to the drugs. I can thankfully say that in all my years of attending den visits, I have yet to see a problem.
It didn't take long before we were done and the cubs were ready to be returned. We formed an impromptu bucket brigade to return them to the den. As we walked away I kept thinking of how much fun these cubs were going to have playing in their giant jungle gym.
NYS DEC heading to bear den
Den #6: Our final den visit of the year was the next day in Steuben County. The drive was a bit closer for us and it was a particularly special day for me because I got to bring my daughter along. She is a junior in high school and we truthfully told her school she was visiting a college class :) . We arrived at the den location and met the homeowners. Although most landowners are pleasant, this couple stands out to me as particularly thoughtful and kind. Perhaps that is why this bear chose a den location that was a mere 70 yards from their back door. That's right, 70 yards. They have a dog pen in the back yard and I couldn't help but think that even though the humans didn't even know the bear was there, the dog must have been able to smell her and her cubs.
Danika Van Niel with bear cub
Again, everything went smoothly with the immobilization of the sow. She had two cubs, one of each gender. At right is my daughter Danika. She had a great experience and you can see it in her face. The mother and cubs were healthy and it should be noted again how close they were to the house. I think this is important for a few reasons. First, it is interesting that a bear can be this close to people and the people didn't even know. That my friend, is the definition of a good neighbor. Second, think about this from the bear's prospective. Why did it chose this location? Was this a prime "favored" location or was this bear here because it couldn't hold a better territory?
We took our usual measurements with some help from Ron Newell, a DEC Technician. Ron is scheduled to retire this summer, so this was probably our last den visit together. Ron has always been particularly helpful with my students, always remembering to explain the procedures to them and making them feel comfortable. Thanks Ron!
Ron Newell weighing bear cub
The veterinarians from the Seneca Park Zoo brought a new gadget with them to help monitor the adult sow: a pulse oximeter to measure blood flow.
You can see it is attached to the bear's tongue.This is non invasive and very interesting to see.
I went to check on the students at the actual den to see their progress. All was going well. Again a bear selected a thorny brush pile. In this photo, Judi is at the actual entrance of the den proper taking measurements.
The den had a small depression and the now familiar "nest". We were nearing the end of the visit and the sow had already been moved into the den. The biologists were rounding up the cubs and I called Danika over and told her where to stand so she could be part of the "cub brigade". Here she is handing a cub over for the last time.
As the biologists stepped back, I asked if we could sneak in for a quick photo. Sure, they said. I laid down and snapped a few photos of the sow and her cubs. I want you to note a few things in this photo. First, see that they have placed the female's paw over her eye to keep it protected from the light until she can wake up and blink again. Next, note that the cubs are already nursing. Bears have three sets of teats: two in the torso region and a third set near the groin. These cubs are nursing on these lower nipples. Third, notice the yellow ear tag. Finally, take a look at the den itself. We try hard not to remove any cover so what you see is what she chose. A few of the grape vines are broken, but she did that for den material.
Danika was the last to take a look. Here she is taking a short video of the action in the den:
The video is nice. It makes you feel as if you are there. And if you listen carefully, you may even hear a little suckling from the cubs
What do I love most about bear dens? It is hard to say. Most people would think it is the cubs. I certainly enjoy them. But I think I enjoy everything about bear dens. I have two dens to report on and each was different and each was special and I am glad I was at both. These were the third and fourth dens of the season for my students and I. I had half of my class at the other two (see previous post) and the other half was with me at these two dens. Here is our story:
Gathering for a den visit
(Canisteo, NY 3/13)
DEN #3: We traveled to the Steuben County of Canisteo and gathered at a beautiful farm. The landowners were gracious and curious. We even had a news crew from a Buffalo TV station tagging along. This bear was part of a study being conducted by Cornell University. We were just happy to be a part of the experience. Our hike was going to be all uphill. Can you make out the large pine tree on the hillside in the photo to the left? Well, that is the approximate location of the den. We headed up, single file and waited on a fairly flat spot until the advance crew gave us permission to come forward. Typically, we are not called in until the bear is immobilized. When we arrived at the den, the biologist were already removing the cubs.... all FOUR of them. That's right, quadruplets. I will have to borrow a photo for you all to look at, because I didn't get a single photo of a single cub at this den. I was busy! I was in charge of processing the cubs and securing what data we could get from the den. In this instance, they never removed the female from the den. The cubs needed to be kept warm so they were removed but mom was only getting a new collar so she stayed right in place.
Chemically immobilized black bear
(Canisteo, NY 3/13)
As I mentioned, this was a bear originally captured and collared as part of a study at Cornell University. Here, the bear wears a nice covering over her eyes in official Cornell red. :) But let's focus on the den. She had dug into the punky root mass left behind from a fallen tree. The tree itself was still there and the projecting trunk made for a roof over her head. When the tree fell, it opened up the canopy and allowed light to penetrate the forest. This in turn allowed a thick thorny growth of shrubs to add further protection to this den site. As exposed as she looks here, she WAS sheltered from the wind and rain, her cubs had an even more secure spot under the trunk and the thorns provided a very thick wall against potential predators. Some of the thorns were cut away in order to access her, but we are close to the date when she will be leaving the den anyway.... In this photo, Robin from the Seneca Park Zoo is taking vital signs. The chemically immobilized bears are constantly monitored. Finally, have a look at the built up "nest" this bear created. Go back and look at Den #1 for this season and see how similar this is to that creation. Since we were unable to take measurements of the entire den, we did our best and I did manage a measurement of the diameter of her "bowl". Forty-three inches across.
Check out the same den, but from the "back" side:
Black bear den in thorny brush
(Canisteo, NY 3/13)
Black bear den
(Almond, NY 3/13)
DEN #4: We made a brief stop for bathrooms and food before heading to our next den. This time, we were headed to State land, so in essence WE were the landowners :) I put the College Suburban in 4WD as we headed up a seasonal road to the correct location. Snowmobile tracks had beaten down the road and its shoulders. Again we waited while the advance team went in. We got the word rather quickly to head on in. This bear, another female, had excavated under some white pine blow downs. This made for a rather snug and secluded location despite being within 80 yards of buzzing snowmobile traffic. The man in the blue hat to the right is Matt. He is the grad student at Cornell conducting this research. I was glad things were working so smoothly for him. This time we found ourselves processing triplets, two males and a female. And just like they did with the last den, they only pulled the female out far enough to access her collar and monitor her health. We would again take limited data regarding the den.
Once mom and the cubs were back inside, I took some measurements of the actual opening. This is not the first excavated den we have been to and I am interested to check for a correlation between these types of dens and certain soil types. Notice how I have to squeeze in between some tree trunks in order to access the den site (not sure which of my students to give photo credit to):
Here is the photo I took. Notice how a strong horizontal root becomes the lintel of the doorway.
The biologists estimated that the den extended eight feet back. How they managed to get a dart in her is a question I still need to ask. Here I am dictating measurements for the data sheet.
FLCC student Eric Gullo holds bear cub
(Almond, NY 3/13)
What do I love most about the den visits? I cannot say. I believe it is that each one is different. Each time I go, I see something new. No two den visits are alike. Heck, no two dens are alike. The people react differently. The conversations with the public visitors are just as intriguing and educational as the discussions with the professionals. Maybe its the chance to catch up with former students that now work for our state agency. Maybe its the look in my current students' eyes as they glimpse a potential future for themselves. I think the real question is: What WOULDN'T I love?
A highlight of my spring semester is black bear den season. I teach a Black Bear Management class at Finger lakes Community College in Canandaigua, NY and the students and I partner with the NYS Department of Environmental Conservation to take data on cubs and bear dens. I have written about previous years here. In these previous posts, I explained in more detail the goals of our work and how the bears are processed. With that in mind, I will not repeat all of that again. If you are new to bears or bear dens (or can't get enough of bear photos) I suggest you glance through some of those posts.
On March 5th, we visited two dens with females and cubs. Our first den went as smooth as smooth could be. We drove to the location near Campbell, NY and got our marching orders. We were a smallish group that included DEC personnel, FLCC students and veterinarians from the Seneca Park Zoo. The walk couldn't have been a half mile and was fairly level. We stopped a hundred yards from the den and let the advance crew move ahead. These are the DEC personnel that will actually be chemically immobilizing the adult. We kept our voices low and listened for the pop from the dart gun. Merely eight minutes after the drug was administered, the adult bear was completely under. It doesn't always happen that smoothly!
Black bear sow in den
Here is a photo of the bear's den. She has created a nice little nest here but notice how little cover from weather or predators this site provides. But just because I don't care for the site doesn't mean it isn't the right one. There are a few aspects of the den I would like to point out. First, have a look at the tree to the right of the den. Can you make out all of the chew marks on it? Let's take a closer look:
Is she marking? Is this a result of boredom? Who knows... One of my students even suggested this was done during labor :)
On the back side of the tree were these scratches. Imagine her sitting up in the den and grabbing a hold of the tree in order to bite it.
The den itself is mostly grape vines pushed into a nice bowl shape. Some of the material appears to have been their at the start of construction but some was brought in by the bear. Look at the den and imagine how tight this will get as the cubs get older.
I noted this bear sign at one other den: Branches bitten off as den material. These were broken off within feet of the den. I am determined to find an unused den by first noticing similarly broken branches.
This bear has been collared for three seasons now. Her first litter was only a single cub. This year, she had twin girls. Both seemed of good size and weight for their age. Cubs are never immobilized and are put in fleece bags to stay warm while mom gets her work up.
Once the work is done, the mother and cubs are returned to the den.
One last shot of the family reunited. Notice the cubs under mom at the lower right.
Our second den was near Wheeler, NY. The den was located right near the large pine tree in the background. Notice how close the den is to the road. Granted, this isn't a major highway, but it isn't a dirt path either.
This bear had triplets. The routine was the same as the last den. An advance crew goes in while we wait for word on the radio. The landowner was on hand and I made a point to thank him for allowing us to come onto his property. He had a few questions about bears in general and asked about the den in particular. Turns out he shared a common misconception with many people I talk to. He envisioned the den to be an excavated site. Although bears do dig dens, those dens are not common in our area. I told him that bears commonly den under brush. Sure enough, this bear was under a blown down tree.
Here, Sasha holds her hand out to the spot where the bear would lie. Again, notice how wide open this den is. At least this one had some substantial cover from the elements.
Above, one of my students (Ben Williams) lies on his back and looks up to estimate the percent cover. We also measure the size of the den, the direction of the opening, and more. But that should be the subject of another entry.
Here is a photo of the den from a distance. We are looking at the "back" of the den. The opening is not visible.
As with all dens, we processed the cubs apart from the mother. They are taken out of their fleece bag only for a moment to tell gender.
The bears in our area are usually born in early January. These cubs weighed a little under four pounds. Check out the canines just starting to emerge
In this case, the collar was taken off but a new one was not put on. This bear was part of a research project through Cornell University and they are done collecting data.
