Animal magnetism--literally (and a note to some young fans)

The dam. 20 January 2014

The dam is in good shape. Maybe better than any of the four  I've seen in the last two years. Let's hope it holds.

You all may recall the neat videos of a fox hunting that I captured last month.

You can see the sequence of three videos here.  

If you look closely at the third video, you can just see the prey escape.

The fox failed to catch its prey. Talking with various friends, the question arose; how often are fox successful in pouncing. Good question, isn't it?  

The answer depends, amazingly, on which compass azimuth they are aligned with.  It seems that foxes have a magnetic sense.  If the fox is facing north to northeast, it's successful in 73 % of its pounces. Facing other directions, the success rate is 18%.

A quick search revealed other examples of animals having some sort of internal compass.

• Water birds are most likely to land in a north-south line.
• Dogs are most likely to excrete while on a north-south axis.
• Migrating birds have a compass map of the world, and use it to know where they are.
• Cattle and deer tend to browse on a north-south axis.
• Loggerhead Sea Turtles have a magnetic sense and use it to navigate.
• Sockeye Salmon have a magnetic sense, and use it to return to their spawning grounds.
• Spiny lobsters appear to have a" magnetic map" that they use to know their location in the world.

That's what I found with just a quick search. There are probably other examples. It seems pretty clear that many animals have the ability to sense earth's magnetic field.

And this sense allows them to do more than recognize a north-south line. Every place on earth has a unique magnetic map; a map that some animals appear able to recognize.

So, after reading this, maybe you are curious to know what direction the fox was aligned when it failed to catch dinner?  Just a little bit south of west. 

Failure.

Fascinating.

Hey, Jack, I'm not making this up myself.  See below for some references.

And a special note to some young fans who left me a message via camera on 19 January 2014 at 2:18 pm. I do read my comments; and I did see yours. I also enjoyed your art installation. It was great. I look forward to your next one. I'm glad you're enjoying the blog; really glad.

More later.

"Pathfinders", by Doug Stewart., February/March issue of National Wildlife.

http://rsbl.royalsocietypublishing.org/content/early/2011/01/06/rsbl.2010.1145.full

http://www.nytimes.com/2012/04/27/science/study-sheds-light-on-how-pigeons-navigate-by-magnetic-field.html?_r=0

http://www.birds.cornell.edu/AllAboutBirds/studying/migration/navigation

http://www.pbs.org/newshour/rundown/2014/01/dogs-poop-in-alignment-with-earths-magnetic-field-study-finds.html

http://www.frontiersinzoology.com/content/10/1/38

http://news.nationalgeographic.com/news/2008/08/080825-magnetic-cows.html

http://www.newscientist.com/article/dn20172-loggerhead-turtles-have-a-magnetic-sense-for-longitude.html#.Ut1UmxAo6M8

Snug as a bug in a rug

the dam and ice-covered pond. 4 Jan 2014.

I had a chance to check the camera and the dam last Saturday. There was snow on the ground, and I was
looking forward to seeing lots of track. I thought I might learn a thing or two about animal activity around the beaver pond.

I did learn a thing or two--just not what I expected.

What surprised me was that there was very little track of any sort in the area, and absolutely no beaver tracks.



I assume that means the beavers are doing what beavers do. That is, staying under the ice where they are safe from predators. They've already stashed a lot of food under the water, in the form of sticks. The entrance to their den is under water so, again, no predators can get at them when ice forms on top of the pond.

This drawing gives shows you how it works, and saves me a thousand words to boot. Can you imagine how our beaver family is happily and safely whiling away the winter under the protection of the ice. They've got a house, food, shelter--everything but high def TV.  And no predators can get at them.

While scouting around, I saw a Great Blue Heron. Probably, it's the same one the camera picked up in this video on the 30th of December.

This is not the only Heron that has benefited from a beaver pond. See this link for another story of the symbiosis of beaver ponds and birds. http://www.treehugger.com/natural-sciences/busy-beavers-save-blue-heron-nesting-ground.html





More later.

The dam is still there

If you live in the Baltimore area, you may have noticed that it rained today. I thought it might be fun to look at the USGS stream data for Minebank run.

Whoa, look at that.

As it usually does during a heavy rain, the stream went in to flood mode. I imagined that the dam was probably overwhelmed. 

I decided to drive up to the park to see for myself. 

I was wrong. The dam was still there. Which was a very pleasant surprise. 

breached on the 15th.

The dam was breached once already this month, on the 15th.  

The beaver pair repaired it pretty quickly, and have been reinforcing it; apparently

repaired by the 22nd.

in good shape on the 28th.

and still holding up on the 29th.

Enjoy a couple videos that I captured recently. 

More later.

Wow. Some great videos.

The lower dam. 15 DEC 2013.

On my last visit to the camera, I made several observations.

1--The last of the two dams has been breached. This is from the rain and melting snow that we experienced recently. As of this writing, there is more snow that will soon melt.

We'll see what happens.






2--There are two beavers in what certainly is a mating pair.I wish I could tell you that from my brilliant tracking observations. But I'm not that brilliant. Keep looking below and you'll see video proof that there are two.

3--Those two beavers have been very active. There are tracks and slides on both sides of Minebank Run. And they are very well used. There also are several medium trees cut down, again on both sides of the run.  There are two food caches in the run, and thee were two dams. The first was washed away completely about two weeks ago. I hope the beavers rebuild the one that still stands.

Meanwhile, I got lucky, and captured some great video of the beaver pair at work.

This picture shows the camera as I set it up on the 7th. You can make out the camera attached to a stump in the left center of the picture. It's focused on a tree the beavers had already cut down. That tree is across the image in the upper half.

I captured a great series of the beavers working. You'll see that it didn't take them long to reduce the tree to almost nothing. They appear to have dragged to branches to the winter food cache in Minebank Run.



So, enjoy the videos below.

More later.

Not a fox hunt, but a fox hunting

I checked the camera today, and was delighted to find a lot of fun videos. I plan to write an expanded post later this week.

Among the videos was this interesting series of a fox hunting.

In the first video, you can see the fox go into its pounce position. It has smelled prey, and is ready to get a meal.

The camera is set up to record video  for 30 seconds. Then it stops and saves the file. After that, it's ready to go again. Sadly, that means that the camera missed the first pounce. Look closely, and you'll see that the fox is about two feet to the left of where it was at the end of the first video. Obviously, though, it didn't catch dinner. It is poking around and trying hard to find the target that it missed.

This third video shows another unsuccessful pounce. Look closely at the lower left and you can see the prey running away, and almost being caught. That's in the beginning of the video. Then you can see one frustrated, hungry fox. 

I was fascinated to see these videos, and hope you enjoy them. Stop by Cromwell Valley Park soon, and perhaps you'll get a glimpse of the fox too. Wish it a Happy Christmas when you see it.

More later. 

Foxes are monogamous...

So, it seems that everywhere I have put the camera in Cromwell Valley Park, I get a picture of a fox. This
led me to wonder how many there might be in the park. Great question, isn't it? Turns out the best answer I can find is something like "it depends".

Apparently, their range varies with food availability, and tends to grow in the winter.  Some sources say that their territories can overlap, although the den areas never do They do travel. One source says that daily travel of over six miles is not uncommon.

I surmise that food is plentiful in Cromwell Valley as there seem to be a lot of fox in the neighborhood.

Meanwhile...we seem to be at the peak of the white tail rutting season. See, http://www.fieldandstream.com/rut-report.

Or see this picture. This guy is after something, isn't he? By the way, be careful driving. The deer are running around everywhere And they aren't paying attention to cars.






The beaver activity seems to be increasing. That is to be expected. Both dams are being built up, and the underwater food cache is growing. Winter is coming, and our favorite rodent knows it.

In this picture, you can see the beaver carrying food into the stream, preparing for winter.








More pictures are below. I hope you enjoy them.

More later.

Great day yesterday.

So,  three weeks a go I thought I would place the camera overlooking a field below the Sherwood Farm. It turns out that I picked one place in the park that has no wildlife. In all that time, the camera picked up one deer--and nothing else.

Good day though, anyway.

I went to see the progress the beaver was making on its new dam. As I was standing there, I heard a small plop in the water.

Seconds later, the beaver appeared. It swam to and fro for several minutes, before going back to hide somewhere. This was just before 1:00 pm. It's pretty rare that beavers come out in the daytime. I don't know if it is significant that this one did, or just a random event.

Either way, I was glad to see it.

Enjoy the pictures.

More later.