Otter, otter everywhere plus a drop of mink

I have a new class this semester, CON 113: Wildlife Field Techniques. Today we visited a river otter latrine in hopes of collecting some scat (see project described here) and checking a camera for a grad student at SUNY ESF. It snowed last night and this morning, so I was certain that any scat we did find would be fresh.

We arrived at Hi Tor WMA in Naples, NY at 2:45 and hit the trail immediately. It was not to be a pleasant stroll but a march with a mission. Tracking was kept to a minimum so we could maximize our time at the site. Will and Micheal, mentioned in my previous otter post, had checked this site on Sunday and Monday with no fresh scat to be found. They were not entirely sure the site was even still in use. I was anxious to have a look myself and see what evidence the camera had recorded as well.

Main latrine site on January 13th

The pond held what looked like fresh slides and tracks at the main latrine site, the one on the beaver lodge. I say fresh, but everything was coated with snow from the morning. We all agreed that the recent wind would have wiped this slate clean over the weekend. So despite striking out on fresh scat, we felt the site was still in use. And the camera confirmed our suspicion.

Elaina had not checked her Reconyx camera trap since mid-January. I pulled the SD card and we previewed enough of the photos to determine that otters have indeed been using the site regularly. We also found evidence of other visitors. Let's have a look (Nearly all photos are uncropped so you can see the date stamps that help tell the story):

January 14th: Will and his Dad glitter old scat

January 15th: Will is back to check for new scat deposited overnight

Jan 16th: Our first otter photos. Although there are only two individuals in this photo, we have multiple images of three otters together. The Reconyx is set to take photos in a burst of three images. Notice the 1/3 on the top of this pic. That means it is the first of three in this series. The camera than takes another burst of three almost immediately. The result is a lot of images (over 1300 in this set) and what amounts to a poor man's video.

I LOVED that otter standing shot. I have never gotten one personally. There are about a dozen shots of otters standing in this data set. Here is just one more (because standing otters are like potato chips --- you can't have just one)

Jan 17: Red fox. And snow.

Jan 25: Wild turkey. In between, we had many more otter pics.

Jan 26: Mink. Like the otter, mink are in the weasel family and like water. Note the obvious size difference though.

If you are not convinced that the otters are much bigger than the mink, here is a composite image of an otter and mink that should do the trick:

Jan 29: Note the time that this coyote showed up to roll in the stinky otter scat.

Jan 30: It didn't take long for the otter to emerge and investigate the new smell themselves

Although most of the otter photos were at night, some were in the day. Since the night pics are shot with infrared, the only way to see color is in the natural light of daytime. This was my favorite daytime photo

Jan 31: "Neither rain nor sleet nor dark of night shall keep these otters from their appointed rounds"

Feb 2: On Groundhog Day, these two coyotes made an appearance. We can assume they did not see their shadows in the IR flash...

Feb 5: The last otter photo taken before we checked the card at about 4pm on Feb 6th.

Clearly the otters are still using the site. So where are they deposting their scat? They don't HAVE to use the latrines, but why would they just stop? Or did they gradually stop and it only seems sudden? We were able to scrape away some snow to collect old scat for a simple diet analysis the class wanted to do as an outside project. Despite the lack of fresh scat, the trip was a success in my eyes. Field work is never a sure thing...

All that glitters is not gold... sometimes it's otter poop

River otter
Muller Field Station, 9/12
Photo credit: FLCC student field study

I am the Co-PI on a grant from NSF to increase undergraduate research at the community college level. Our approach is to develop some sort of intervention at the freshmen level to introduce students to research (case studies, for example) and actual participation in research projects in second-year classes. I have two classes with a research component: Black Bear Management (read about their exploits here) and Wetland Mammals. Among other things, the grant has allowed us to partner with other institutions and individuals. That is how we became involved with a river otter research project being conducted at SUNY-ESF. Elaina Burns, ESF Master's degree candidate and FLCC alum, is attempting to survey the population of river otters in the Finger Lakes Region of NY. Her work centers mostly around otter latrine sites where she is collecting scat samples for DNA analysis and setting camera traps for visitation rate and group size data. My interest in the project goes beyond the short-term involvement of my current students to the long-term mimicking of her protocols on a much smaller scale to monitor the otter population in our part of the Finger Lakes.

One of the great things about research is that it often promotes MORE research. As the river otter scat samples are being processed in the Biotechnology Lab at FLCC, student Micheal McIntyre wondered if we were doing all we could to preserve the DNA in the samples after collection. After a literature search of other studies, Micheal proposed that we collect some scat this winter (our off-season) and see if there was a difference in success rates of DNA extraction among three different collection protocols. Thus, a mini-research project was born! "Mini", but with some very practical applications to our work and the work of others. It is expensive and/or time-consuming to collect otter scat. We cannot afford to squander these samples (waste the "waste" if you prefer) so knowing how to store the samples to preserve any otter DNA present is very helpful.

River otter tracks
(Hi Tor WMA, 1/13)

One of the Conservation Technicians at FLCC (Sasha Mackenzie) had discovered an active otter latrine site in December. But the winter had arrived since then and we had about two feet of snow on the ground and the pond would surely be frozen over. What if the otters had moved on? On January 2nd, she and I strapped on snowshoes and went to visit in order to determine if it was still active and how feasible it would be to collect scat from that location. We arrived to find not only an active otter latrine, but a real live otter to boot! We set up a camera trap and headed back to the vehicle, discussing the logistics of collecting the fresh scat samples Micheal would need for his study.

On January 12th, I revisited the site. Will (a current student at FLCC) and Alyssa (FLCC alum) made the trek as well. It was an enjoyable day. The weather was nice (despite the rain) and the distractions were many. We had lots of different dog tracks to inspect. We followed a fisher for a while. There were insects about. We approached the pond in stealth mode, hoping to see an otter. We were not disappointed. Three otters were making the most of a small hole in the ice. Up and down and over and around the otters writhed and tumbled in the hole.

River otter latrine
(Hi Tor WMA, 1/13)

The show was short and we set to work. We visited what I would call the secondary latrine site first. I introduced Will to the wonderful world of otter scat. Note the hole that the otters had been using to access the shore. There were a few scats present at that level, but the real show was atop the mound. The otters were climbing the small stump and leaving scat as high as possible. You can even make out a very steep slide (just to the left of the center of the mound) where they would make their way back down.

River otter scat
(Hi Tor WMA, 1/13)

We found a fresh looking scat with some associated jelly and Will took out the collecting gear (Jelly is produced in the otter's intestine and is thought to help lubricate the system to help with the sharp bones and scales).









The jelly is preferred over scat in DNA studies for the simple reason that the jelly is 100% otter whereas the scat is mostly DNA from what the otter consumed with some otter cells mixed in.

Collecting otter jelly
(Hi Tor WMA, 1/13)

Sample tubes

First order of business is to glove up. We do not wish to contaminate the DNA, but we also do not wish to degrade the sample in any way and humans carry chemicals that are designed to do just that. Will opened the first collection tube and used the attached scoop to collect the jelly. A third of the sample goes into 70% ethanol, another third goes into a concoction called DET buffer and the remaining third is stored in no media at all as a control. All vials are then frozen until they are processed in the lab. From there, we headed to the main latrine. I was anxious to see if we had any photos on the Cuddeback Attack camera trap.

Beaver girdled this tree
(Hi Tor WMA, 1/13)

The otters appear to be using an abandoned beaver lodge as their home for the winter. I am somewhat familiar with this location and know there have not been beaver here for many years. Beaver leave their mark on the landscape for some time. It is common for otters to use beaver lodges as their own. Sometimes they have to "evict" the current owners.






Here is the view from the camera trap. You can see the beaver lodge in the foreground and the pond beyond. Even from this distance, you can see the area near the shore is COVERED in scat.

River otter latrine site
(Hi Tor WMA, 1/13)

The camera trap indicated seven photos had been taken. I was hoping for more, but we had so much snow melt that I believe the camera was now too high to be triggered! I changed SD cards and we proceeded cautiously out to the latrine site. It was hard to tell exactly where it was safe to step.This is literally the largest river otter latrine I have ever seen.

We found more jelly as well. Jelly can come in many colors including clear, yellow, green and the putrid color you see here :)

River otter scat and jelly
(Hi Tor WMA, 1/13)

The protocol allows for collecting only fresh scat samples so we have the best chances of recovering DNA that  can be analyzed in the lab. As the scats get older, the DNA degrades. This study calls for the latrines to be visited daily until we have enough scat samples. A different team was to visit the next day. How would they distinguish fresh scats from all of these older ones? With all the rain, EVERY scat looked fresh. Answer: glitter. Glitter is ideal. It is cheap, non-toxic and comes in a shaker. Will was the head glitterizer...

Before:

After:

It took a LOT of glitter....

Adding glitter to otter scat
(Hi Tor WMA, 1/13)

On our way out, I turned the camera trap back on. As we walked back, I found my thoughts straying to the SD card in my jacket pocket. It had been a long time since I got a good story out of a camera trap. Did I get anything good at this set? Yes. Yes, I did.

A pair of coyotes had visited the site.

Eastern coyotes
(Hi Tor WMA, 1/13)

But the prize were my two otter photos. One showed three otters together:

River otters
(Hi Tor WMA, 1/13)

Notice the coloration of the throat. River otters almost always show that lighter underside to the face and chest.

The other shows a fascinating aspect of river otter travel. Otters are known to slide on snow. In fact, they are known to slide downhill, on level ground and even UPhill. I wanted to get a photograph of an otter slide to add to my classroom lecture on this species. I know I can pull a photo off the internet, but I pride myself on using as many of my own photos as possible. So imagine my delight when I got a photo of the otters in action. Check out this tandem slide!

River otters sliding
(Hi Tor WMA, 1/13)

Not one but two otters sliding side by side. Amazing. And look at the older otter slide on the left of the photo. This is great! A few minutes later and there would have been enough light to have this in color. How am I sure these are otters and not the similar looking mink? Well, I was there at the site and know these animals are far too big to be mink. Secondly, I can see the light throat mentioned above.

In my Wetland Mammal class last fall, one student group had great success with capturing otters on their camera trap. The camera itself was jostled so everything is at an odd avant-garde angle.

First, an otter. Remember, something caused the camera to tilt. Look how sleek this guy looks!

River otter
(Muller Field Station, 9/12)
Photo credit: Student field study

Now a mink. The camera angle has not changed. Look how much smaller the mink is. Note the lack of a light patch on the throat and chest.

Mink
(Muller Field Station, 9/12)
Photo credit: Student field study

I will keep you updated on these projects as they progress. For now though, remember the lesson for today: "All that glitters is not gold..."

Check out Alyssa's blog entry on this encounter at Nature in a Nutshell.

Otter latrines and zebra dung middens

River otter scat
(Muller Field Station, Richmond NY 2/12)

Today's post ain't pretty, but IMO it is interesting. The last time I was at our Muller Field Station, we visited an active river otter latrine. This is exactly what it sounds like: a place where river otters repeatedly defecate. They are sometimes called toilet sites or just toilets. I always make sure I tell my students that otters do not exclusively defecate at toilet sites, but they do so often and for a purpose. Think of the amount of information that can be conveyed in scat. Certainly one animal could tell what another individual was eating, but the vast majority of information is chemical (largely scent). And don't think of the scat itself as the main source of info, but rather the other products that are left behind probably tell the story better. Cells from the intestines mixed into the scat, hair left behind either through the process of ingestion or through the animal rubbing and rolling, scent from glands on the animals body (often anal glands that purposely deposit scent with the scat), etc. etc. What a waste to think of scat as just, well, waste!. At left is a photo of some river otter scat. There is a large quantity of undigested fish scales mixed in with a few aquatic inset parts. We resisted the temptation to pull it apart as our guests from Jamestown Community College were there to collect such items for later DNA extraction. This particular scat was part of a very active latrine site. The next photo shows the whole latrine. Notice the muck that has been pulled up from the channel. At least river otter and beaver do that and it is often hard for me to be 100% certain which species is responsivble. Even at this latrine site, I would not be suprised to find that a beaver had done this.

River otter latrine site
(Muller Field Station, Richmond NY, 2/12)

River otter latrines are particularly interesting for several reasons. As seen above, the scats often contain lots of interesting stuff that provide information regarding the diet of the animals. Second, the latrines make great places for camera traps and last, otters often leave behind another substance besides scat: jelly. In 2009, I volunteered for a week on a river otter research project in British Columbia. Our main task was to find fresh jelly (called otter or anal jelly in the literature) and collect it for analysis. The jely is actually produced by the otters so it is 100% otter DNA as opposed to the scat itself that has the DNA of the animal(s) that were consumed to help confuse the issue. As a general rule, otter jelly is preferred for DNA analysis for that reason. Here is one particularly interesting photo of fresh otter jelly from British Columbia:

River otter scat and jelly
(Victoria, BC 7/09)

Have a look at that string of jelly. I have always imagined that the otter was standing in one spot and gave a mighty squeeze rather than the otter moving as it emitted the jelly. Regardless, that is what fresh jelly looks like (although it can come in slightly different colors as well as in clumps rather than strings -- we even found depostis that looked as if the scat and jelly were combined that were dubbed jelly-scats).

On our family vacation to Africa this summer, we witnessed a different species of mammal deposting scat in piles. The very first Grevy's zebra we saw showed us an interesting behavior. He walked right up to a large pile of scat, sniffed and then added his own to the accumulation. This is a common behavior among zebra males as a way of marking their territories. The books (and our guide William) say that these are created along the boundaries of two males' territories. They are called "dung middens" rather than latrines...

JVN:"Hey! A Grevy's!"

DVN: "Is eating that poop?"

DVN:"DAD! Stop taking pictures. This is gross."

In truth, not everyone was as excited to see this behavior as I was...