Monday, February 27, 2012

Riparian Walkers

I had almost forgotten about this camera set.  The pictures below were part of a monitoring project I ran on property owned by the North Carolina Zoo.  From February 2010 to July 2011, we conducted a vertebrate invenotry on this property, which included drift fences and coverboards for small vertebrates, radio telemetry on Eastern Box Turtles (Terrapene carolina carolina) and, of course, camera traps for the big guys.

The camera that took most of the pictures below was placed along a nice riparian corridor for a few months during this period (Feb 17 to April 19, 2011) to see who was hanging around.  This was one of several cameras  deployed at various locations throughout the property.  Unfortunately, most of our camera trap captures on the site were of White-tailed Deer (Odocoileus virginianus).

The Riparian corridor provided our best variety.  It also represents my only venture into the realm of ScoutGuard cameras.  I can't even remember what model it was (the SG550?).  Anyways, I have to admit that I was at first very impressed....but this waned after a series of malfunctions, returns and straight-up inconveniences on the part of the camera (including an external remote..which you had to bring into the field with you and plug into the camera to program it).

Anyhoo....some neat pictures were captured near this heavily wooded stream crossing.

A juvenile Red-Shouldered Hawk (Buteo lineatus) flew down to the stream on back-to-back days for a drink?  Trying to grab a frog?  With alittle help from my buddy Bill over at The Future Of Birds, I was able to definitively identify this species!  They like woodlands associated with water, so it makes sense to see them here.
Above: Find the Buteo!  See the lower left-hand corner of the pic....

Above: Find the Buteo II!  In the background, standing in the water again.

The red-shouldered was by far the most unique thing captured by this camera.  Although, there were some neat pics of Racoons (Procyon lotor) wading around for frogs and fish.

And, of course, what series of pictures from a set in North Carolina would be complete without White-tailed Deer?  I quite liked the one below....with the reflection on the water......

Was also neat to get a shot of an American Crow (Corvus brachyrhynchos) coming down for a sip.....

Throw in a ubiquitous Eastern Gray Squirrel (Sciurus carolinensis).......

...and a feral puddy tat....

...and that about 'rounds it out for this camera set (and, in fact, for the site).  Although we did get pics of two other species from other locations at this site, they weren't some of the riparian walkers.

There were a few precious shots of "talking dogs" (Canis latrans).....

...also one lonely Gray Fox photo (Urocyon cinereoargenteus) at a scent station..... long as I'm posting pics of feral puddy tats.....I might as well show a 'coon hound, that had to belong to a tresspassing hunter.  He stopped by for a sniff at the scent station I put out at this spot.  Although there are stray dogs on-site, there's no way that a stray has a reflective collar with a GPS unit strapped to his neck......

Friday, February 24, 2012

Yes.....LET'S Talk About the Weather: winter's stubborn ways.

In an effort to play off of a post by the good fellas over at Camera Trapping Campus (see Let's Talk About the Weather, posted Feb. 23, 2012).....I say, "yes, let's do talk about the weather!"

Here in the upper Midwest, winter has decided it's not giving up so easily.  These pictures were from this morning after several inches of wet heavy snow fell and clung to all available surfaces.

Now, for folks who don't like snow....this would be annoying for late February....

....but....I'm alittle weird....

...and I was glad to see some of the white stuff again.....

...especially when it looks this incredible!

(although I can't help but be slightly envious of the 75 degrees and sunny that they are getting over there in California!)

Tuesday, February 21, 2012

Advanced Ecology Lab Week 2 & 4: Taking it down a notch.......

Above: the exciting world of sitting behind a computer and conducting GIS analyses!

Although field work is really what the lab for this class is all about (see here and here), occassionally you have to come inside and analyze your data.

The first time we're doing this in class involves GPS data and Geographical Information Systems (or GIS).

GIS is a great tool to have experience with.  In fact, an ecologist interested in monitoring, biogeography, resource selection (e.g., habitat selection, etc.) and spatial ecology can do these much more effectively if they can use GIS. I've said, it's an invaluable skill to learn.....but that comes at a cost.

The software can be amazingly frustrating to work with (powerful though it may be).

It's finnicky.  It's picky.  It occassionally works or doesn't work for no other reason that I can determine aside from there being gremlins inside of the computer.  Furthermore, every time the manufacturers update the software, one has to relearn how to do alot of simple commands...which is annoying.

However, if you can learn to use it and not get frustrated, you are on your way to knowing an invaluable skill (and a marketable skill, for all of you budding ecologists). 

Many kids of the age to be undergraduates in college have grown up with technology, which works in their favor for learning GIS.  However, they have grown up with technology that is very user-friendly.  If it doesn't work...most technology the kiddies play with has buttons they can smash around on and eventually get what they want.  GIS is not that way.  It is not intuitive and will not work itself out if you "play around" with it.  So not knowing the proper steps to conduct an analysis (or not following the steps you've been provided) will result in heartache.

Ultimately, one has to look past their frustration to see what GIS can provide and how useful it really is.

All of this must make it sound as if I don't like GIS, which is not the case.  I love it!  It's an amazing tool. 

Yet, this fact may not sink in until after one is done spending hours in a computer lab......has gone home to unwind....AND had a chance to think about some of the cool stuff they've made with GIS.


But before you have to sit behind a computer, you get to go out in the field and collect some data!  In our case, we were using GPS units to delineate habitat boundaries on-site so that they could later be uploaded on an aerial photo in GIS.  This was done several weeks prior in the field.

First, the student groups got together and tried to determine which group would collect GPS points for which habitat communities by reviewing an aerial photo of the site. 

This is an important step.  Collecting data incorrectly, or not being clear on which groups would be delineating which areas can lead to overlap and wasted time....OR not collecting enough data points (which the students learned the hard way).

Next, each group headed out to their locations to start collecting data.

....once at a desired location, the unit is fired up and a reading is taken.

Next, the data points are organized and appropriately formatted into spreadsheets.  This is where the headaches can arise.  The GIS software we use is very, very picky.  A space in the wrong place, an incorrectly formatted value, a spreadsheet saved incorrectly all can result in things not working for no apparent reason.  Perserverence is neccessary!

But, once you are may just get lucky enough to have a cool aerial photo with your habitat community types perfectly delineated as a polygon based on your GPS coordinates.  You can also measure the areas of a given habitat type to determine the proportion it is of your overall study site (a very useful bit of information).

Above: one of the students' final maps.  All of the data points were collected in the field.  Note that the polygons don't follow each GPS point exacty (particuarly obvious in the upper right).  We made these as Minimum Convex Polygons, and thus the program basically connects the outer-most dots when making a polygon.  A good first stab and it took most of a three hour lab to get this.  If making maps for this site was a semester long project, the example above would need to be refined.

Above: another one of the final maps made in lab.  This one contains different-colored polygons that encircle various habitats present on-site ("disturbed", woodland, oak savannah).  The blue polygon represents where the tree quadrats/samples were collected during week 3.

The students made some nice looking maps.  Unfortunately, working in the GIS lab meant we didn't get out to our camera traps....and we are on a hiatus during week 5.  So, three weeks worth of pictures will be forthcoming in the near future.

Friday, February 17, 2012

The White-Footed Mystery........

I am frequently stumped by things I observe when out in the field. 

This morning (February 17th) was no exception.

I was walking along the edge of some trees behind the house with the dog when a something caught my eye: a small rodent laying on its back in the grass.  It was completely intact and almost appeared to be sleeping.

Now, I went to college....and as a result I was able to deduce that it was unlikely this rodent was actually asleep on its backs in this exposed location.  So, using all of the limited power in my brain, I came to the conclusion that something must be up ( was early in the morning and I hadn't quite gotten enough coffee, afterall).

I leaned over and nudged the critter (a White-footed Mouse, Peromyscus leucopus), half expecting it to stir.  White-footed Mice are not obligate hibernators (i.e., it is not a species that goes into a full state of hibernation that it cannot be aroused from by external stimuli). Yet, they will go into a facultative state of torpor that can be brought on by lack of food or a decrease in temperature (Lackey et al. 1985).  The rate at which they enter this torpor is highest from mid-December through mid-February (Lynch et al. 1978).  Apparently Lynch and his colleagues found that these states of torpor also typically occur in the morning, and last for at least 3 hrs.

So I was under the assumption that I had stumbled across an individual that had gone into one of these torpid states, and perhaps fell from a nest site in a nearby tree (they are semi-arboreal and known to often nest off of the ground; Nicholson 1941).

But my touch revealed the colder truth.  The mouse was frozen solid, eyes staring blankly back at the grass upon which it lay. 

My next thought was that perhaps a bird of prey had grabbed the little critter, killed it, and dropped it here on accident (or dropped it and it died due to the fall).  I inspected the body for damage or wounds of any kind, and found none.

It's also possible that the mouse fell out of its nest in a semi-conscious state and never woke up enough to return to it's nest before freezing.

The possibilities are limitless, I suppose.

So, the question remains:  what killed the little White-footed Mouse? 

I suspect I'll never know.

Literature Cited:

Lackey, J.A., D.G. Huckaby, and B.G. Ormiston. 1985. Peromyscus leucopus.  Mammalian Species No. 247. pp 1-10.  Published by the American Society of Mammalogists.

Lynch, G.R., F.D. Vogt, and H.R. Smith. 1978. Seasonal study of spontaneous daily torpor in the white-footed mouse, Peromyscus leucopus. Physiological Zoology 51:289-299.

Nicholson, A.J. 1941. The homes and social habits of the wood mouse (Peromyscus leucopus noveboracensis) in southern Michigan. American Midland Naturalist 25:196-223.

Wednesday, February 15, 2012

Phenology: The "Talking Dog" Earns Its Name

Last night (February 14th) love was in the air!  And on Valentines day, no-less!

As I took the dog out so he could release some unwanted metabolic waste before bed, I heard the 'yotes (Canis latrans) howling in the field across the street.

The timing is correct.  Although January is generally considered part of the breeding season for this species, Hartley T. Jackson stated (1961) breeding in these parts is primarily in February.  Coyotes will howl at various times throughout they year, but they are known to be particularly vocal during the breeding season.  They may howl to attract mates and to warn potential rivals of their presence.  Howls provide other non-breeding functions: communicating with a pack that is spread out (hunting, for example) and to warn other packs or groups of their presence (an early warning system to avoid tresspassing).

This is the first time I've heard the coyotes calling this year.

I'm assuming there will be more pictures of them to come.

But, for now, I'll placate you all with some recent pics from cameras that Dave is still taking care of in North Carolina.

Note that the first picture is of a pair.

The second pic is a nice one....I just wish the subject was looking towards the camera!

In general, the 'yotes at these cameras did not show themselves from July through December.  Since then, we've more commonly captured pictures of them.

For more information on eastern Coyotes....check out this recent paper published in Southeastern Naturalist:

L.L. Mastro. 2011. Life history and ecology of coyotes in the mid-Atlantic states: a summary of the scientific literature. Southeastern Naturalist 10:721-730.

Sunday, February 12, 2012

Advanced Ecology Lab Week 3: Red-tails and Tree Quadrats

There is no type-o in the title.  I meant to jump from week 1 to week 3 in my posts.  The stuff the class did during week 2 is associated with week I'll talk about it later!

The cameras picked up some interesting stuff over the past week.  Again, the White-tailed Deer was in greatest abundance.

But...this week we were also fortunate enough to get a nice shot of a Red-Tailed Hawk (Buteo jamaicensis).  The first Red-tail I've caught pictures of on a camera trap (although not the first bird).

Interestingly, two weeks ago, we saw a pair of red-tails flying overhead on-site and screaming at eachother.  One had a small mammal in its talons and the other didn't.  I wonder if there was some kleptoparasitism about to happen?

Tree Sampling:

This week, as part of the battery of assessments being conducted of the property we are focused on, students conducted a tree survey.  This involved each group measuring out five non-overlapping "quadrats".  A quadrat (or sample plot) is a way to radomly select certain areas in a tree stand to sample, considering that measuring every tree in a forest is not practical.  Each quadrat measured 33 ft X 33 ft (or 1/40 of an acre).

So, the first step is to measure out the quadrat.

This can be difficult with thick underbrush....

Then, comes tree identification.  Obviously, identifying trees in winter can be challenging.  There are no living leaves to work with.  So, one is stuck using bark, twigs and leaves near the base of the tree that you hope came from the tree in-question.

Luckily for us, the diversity of trees on-site was not huge (probably the only time something like low diversity can be considered "lucky").

There is the Locust (Robinia sp.)....with its deeply furrowed bark.....

...the Box Elder (Acer negundo)....Box Elders tend to hold on to seed pods (the commonly referred to "helicopters") in the winter.

...the Black Cherry (Prunus serotina)...check out how much darker its trunk is compared to the Elm (I think) just behind it and to the right.  The bark will also look scaly, like potato chips.

....the Mullberry (Morus alba)...although this picture doesn't show it well, they have a more "yellowish" tinge to their bark.

...the Hackberry (Celtis occidentalis) mistaking that warty bark, with the roundish nodules....

...the Red Oak (Quercus rubra).....oaks often hold their leaves in the winter....although there are a few sporadic White and Bur Oaks (Q. alba and Q. macrocarpa) on-site, the leave shape of these three species differ.

...the White Pine (Pinus strobus; the thin tree with the smooth bark in the background to the left) and the Red Pine (Pinus resinosa; rough bark more in the right foreground)...also White Pine needles occur in bundles of five, and Red Pine needles occur in bundles of two.

...and, of course, the terribly invasive Cathartic (or European) Buckthorn (Rhamnus cathartica).....its bark almost looks like it would belong to a black birch tree, or something....

For every tree within their quadrat that was of the appropriate size, students measured diameter at breast height (DBH).

The data the students generate can then be used to calculate tree frequency, also relative and absolute density, and dominance.  Students can also calculate average number of trees (and circumference) per acre.  Finally, using adaptation scores for each species, students can calculate compositional indices for the site, that can help classify what type of vegetative community is present.

...and although it was alittle cool out and the underbrush ocassionally got alittle thick, you can see they had a miserable time.....

Wednesday, February 8, 2012

Bloody Concession Vs. Dogged Determination

Some bucks have thrown in the towel when it comes to keeping their antlers.  Of course, I'm anthropomorphizing....but...whatever.

Also, to be fair, this buck didn't truly concede.  It's just a decrease in daylength that resulted in lower testosterone levels, which stopped antler growth and started the process of detachment.  Once the connection between the antler and the pedicel (i.e. raised "platform" on the skull where the antlers arise from) starts to weaken, it probably doesn't take much.  Perhaps the antler got caught up in a dense thicket....or was bumped by a tree.....and just fell off.

Interestingly, it's actually the increase in daylength in March/April that results in greater testosterone production, which stimulates antlers to grow in the first place.  So, daylength and hormones play important roles in annual antler development.  Also, the size of a buck's rack is believed to have a great deal to do with diet. 

As the Wisconsin Department of Natural Resources website states:

"During the early spring and summer, deer graze and browse heavily to replenish the fat reserves they depleted during winter. Does must obtain energy to make the milk that they use to nurse their newborn fawns. Bucks use some of this new energy to grow antlers a process that requires a substantial amount of protein and minerals. Although spring nutrition is important for body and antler growth, deer possess adaptations that allow them to prosper in areas with mineral deficiencies. For example, deer deposit minerals in their skeletons throughout the year. Then, during antler growth, they mobilize these minerals to help the antlers grow strong. A second adaptation is the deer's ability to change absorption rates of minerals in their stomach. When using large amounts of minerals for antler growth, deer siphon more minerals from their diet. Deer rely on plants for these minerals, and they select plants offering the highest mineral concentrations."

  We are currently in the midst of the "shed hunting season", or the time when deer drop their antlers and collectors start pounding the ground in the hopes of finding them.  Yet, that doesn't mean there is a narrow and definitive window within which bucks will drop their racks......OR that its a forgone conclusion that they'll drop those bony burdens by a specific time each year. 

Basically, one would expect them to be dropping around now (Jan/Feb), although one wouldn't be shocked to see bucks holding their antlers for a few weeks yet. 

Case in point: this individual below (captured at the same site as the one above).  He still has both of his antlers, and the date of these photos is several weeks after the above picture was taken.

So, based on the information I've outlined above, the presence of the antlers on this buck doesn't surprise me that much.  What does surprise me is that this guy still appears to be pushing his luck with the ladies.  We are quite a ways past the main part of the rut here (see figure below, borrowed from here).

However, a doe that has not bred will apparently continue to cycle into March, which may be the trigger for the interaction below.  Althoug with the high density of deer 'round here, I can't believe this doe couldn't find someone to breed with until now!  Furthermore, this guy must be chalk full of testosterone, or at least still has just enough to give it the old "college try".

She comes back a bit later looking alittle "roughed up".  Not sure if actual copulation occurred....but an interesting example of late season breeding behavior, it would seem.

So, although it's mostly deer pictures these days, which can get alittle least we're getting some interesting phenology and behavioral information.

Literature Cited:

Gordon, I. 1997. Controlled reproduction in horses, deer, and camelids. C.A.B. International, Volume 4. (note: I have not actually read this bit of literature...but I used a version of a figure from this article above).