species level

[salamanderhunter]

I was just wondering if anyone has any experience pegging mice, birds, reptiles, etc... down to the species level. How about aquatic invertebrates? Obviously a crow is different than a grouse, but what about the songbirds beyond hoppers and walkers...or shrews and voles that are about equal in size? I'm guessing that with enough dirt time a person could get close. I'm going to start working on reptiles/amphibians and see how far I can get. thanks....joe

[naawibiimikawaan]

I don't know much about the reptiles and amphibians....haven't had an opportunity to track them much....but the small mammals are do-able.

A couple things to keep in mind.

#1 Habitat....often the only thing that separates vole or mouse species from one another is habitat.

2. Take very good measurements and really look at the morphology of the track. For instance, a norway rat has similar sized tracks to a chipmunk, and they can often be found around houses and such, but a rat has much thinner, longer toes....that sort of thing.

3. Gaits are often different too. Voles tend to trot, but not always. Mice tend to bound, but not always. Both will walk when feeding in cover. But again, habitat will help. Shrews have different ways of moving as well and their tracks are often much smaller....I've never found clear shrew tracks for study...hopfully that will change this summer.

But it definitly can be done and quite accurately too. Sometimes you just won't know, but if you take good measurements, assess the possibilities as far as habitat, look closely at gaits, behavior and morphology, you will answer more questions than not.

Check out http://www.animaltrackingbasics.com. Also, get the new book by Jon Young and Tiffany Morgan called animal tracking basics. It's an awesome book, and, as a bonus, contains the 4 page shikari orientation journals. You can download these off the website. The journals really force you to not make quick judgements, and go through all the possibilities. It really helps me to draw the most info out of the tracks.

Nick

[salamanderhunter]

thanks! That's pretty much what I was thinking. Thanks for the link and the book info too...

[paul vallandigham]

If You use Tom Brown's Field Guide to Nature Observation and Tracking, he has tables in the Appendix that can be of great help in identifying small rodents. You have to use every category, gait, shape, toes, trail width, step interval, walking stride, running stride, and then you need to use the page reference to go back into the test to review the information about habitate, and food sources. Don't skip anything. When you get to know that habitate that you are living in much better, you will already have a good idea of what small rodents live around you, and what kind of food is available to support them. If you want to find mice, or meadow voles, ask the hawks, owls, fox, and coyote. all feed on voles frequently, and visit area nests on a regular basis. Whther you have shrews living around you is a function of how many mice, as they have the fastest metabolism of any mammal, and must eat constantly. They have to have meat on a steady basis, or they die of starvation. Because a shrew has to be small enough to chase down mice in their runs, its about as difficult to find a shrew as any other mammal on earth. They often are found by accident, caught in mouse traps.

The same as finding members of the mink family, namely the small ermine or sable. They exist, but are difficult to locate, even when you live in the North woods. Trappers run across them, again, sometimes when they are caught in traps set for larger animals.

As to song birds, If you study habitat for all birds, and pay particular attention to how HIGH off the ground they make their nests, you will find that certain species prefer to stay within a relatively narrow range of height off the ground. The hoppers will land on the ground to eat a grub, or worm, or some seed or nut, and then fly back up to their safety zone. Because small song birds are also preyed on by owls and hawks, they also seek certain kinds of bushes and trees, that give them cover from below and above, and when they land on a perch, it is inside that cover, and not out on a limb.

For example: The Crow is a large bird, basically a scavenger. It uses lots of look outs, as a groups. to protect individuals from attacks by owls or hawks. The Crow has no reluctance to sit out on a high limb, where he can see a lot of ground, as well as what is in other trees. The crow both hops and walks. You identify him because next to the turkey, the crow will have about the biggest track you will find for a ground walker. Also, the shape and number of toes tells you that the track is made by a crow.

So, knowledge of local habitate, kinds of predators, and food sources for any given species are essential to identifying specific species of small animals. I have only see clear vole prints once in my lift, and that was in a dusting of snow on some boards in a field, where a vole walked in the shaddow of a stack of wood. Think of a pencil ereaser with 4 points sticking out like the point of a crown, and you will recognize the tracks. OH, if you are looking at those tracks in snow, you will see his tail dragging between his legs and between his tracks, too.

[salamanderhunter]

thanks for the tips...I've got to chew on this, and get some dirt time in. I never thought about shrews eating mice

[paul vallandigham]

Without an extensive meadow vole colony, I don't think shrews can survive. They have to eat 24 hours a day, because of their metabolism. Read several field guides and text books about shrews to understand their special needs. Its good practice to use in studying all species. Same with birds. You will be surprised at how few sources ever consider talking about the comfort zones the birds live in, and the habitat requirements of each species.

[salamanderhunter]

Just as a coincidence...my nieghbors cat killed a shrew yesterday. It is strictly an indoor cat.

[paul vallandigham]

EIther caught in a trap set, or brought home by the family cat is about the only way most people will ever see a shrew. These animals live underground and are nocturnal. They have excellent night vision that is blinded by sunlight. Even in zoos, its next to impossible to see the shrew active and out during the visiting hours.

[naawibiimikawaan]

Shrews also rely heavily on insects and worms...if my memory serves me correctly. I've seen only a few...mostly shortailed shrews...one of which I found on the steps coming home from work (he couldn't get out) so I put him in the yard and the next morning he was gone.
I've also seen a masked shrew, and only because it was dead on a trail. It's amazing how many shrews seem to die on a trail! Anyway, this guy was TINY....the feet couldn't have been more than about 3/16 of an inch long....and that was the rear feet....in fact, they may have been smaller.

There is also a certain shrew that can run on water!

If you ever get a chance, do some owl pellet dissection. I once found five complete shortail shrew skulls in a single pellet. In certain areas around here, they seem to be the most common owl food.

Nick

[P. T.]

Joe,

The best way to start to learn those minute differences is to live trap animals and run them through track-plate set ups. This way you have KNOWN examples from which you can compare unkown tracks found in the field.

Most animals beyond genus are only different in size by a couple of millimeters, and sometimes not even at that. A micrometer will help you start to see those size differences.

However, there are a few exceptions; for example, one type of vole has 5 plantar pads, while most other voles have 6; or the water shrew has a stiff fringe of hair around its toes and foot to help in swimming and other shrews don't
These morphological differences are not found in most tracking books
(not in any of tom's and not in animal tracking basics)
You will want to get good mammal guides: peterson's latest edition by fiona reid is excellent, california's mammal guide is superb, etc..

Habitat and gait, cannot be relied upon by themselves.

One last thing, All the Genera are distinguishable by tracks, its the Species that are very similar and usually only differ in size.

Go out and trap some animals and have fun.