More on Teeth and Feathers

I asked my tracking mentors to look over the Turkey Tale post and tell me what they thought.  A couple of them commented on that post directly, adding some great information.  Another (also named Dan) sent me an email and I asked if I could share it here to show how the process of discussion among Naturalists works.

Great story, man…engaging, inspiring, great role modeling for mentoring, tracking, and follow-up research.

Technically – looks good with the exception of one line that stood out to me – the one about canid vs felid carnassials. It’s incorrect.

Check out this paper to learn why:

http://www.mun.ca/biology/scarr/4505_Felid_Teeth.htm

Thanks for asking, Andy.

dg

My reply

Thanks for the paper and the complements.

I got that info about the teeth from Elbroch. In Mammal Tracks pg 737-8 he says “Bobcats, which have less developed carnassail teeth than canines do, leave much more ragged sign… The appearance is one of chewing through feathers rather than cleanly shearing them.”

Do you think the observation of “more ragged sign” etc is incorrect or could something else account for that appearance. I agree after now looking closely at some pictures of bobcat skulls that the carnassials look pretty well developed. Have you encountered any large bird eaten by a bobcat in the field? How were the feathers dealt with?

I enjoy the back and forth of question and discovery. If anyone has experience with mammalian predation of birds please add your two cents in the comments section.

 

Below is what I felt was the most pertinent part of the paper Dan mentioned.  There is more in this interesting paper on the evolution of felid teeth, see the link above.

If we examine the cheek teeth of a typical cat, whether it be a lion or a domestic tabby, we see that by far the most important feature is the scissorslike arrangement of the upper and lower carnassials, the meat-slicers. This arrangement is enhanced by the fact that the articulation for the mandible or lower jaw, the hinge, is in line with the intersection between the carnassials, just as in a pair of scissors. The other premolar teeth, although by no means unimportant to the animal, are relatively less significant. When we examine the cheek teeth of a saber-tooth such as Homotherium latidens, a species fairly common in Europe around 1.0 Ma ago, we see an even greater specialization in slicing, with the anterior check teeth much reduced in size.

The dogs have carnassials too, but they are only part of a dental armory that is augmented by many more premolars in front of the carnassials and by the crushing molars behind them. The dog is therefore a generalist when it comes to food-processing ability. In the hyenas the specialization is in almost entirely the opposite direction to the cats, with the development of huge, conical, bone-cracking teeth. Spotted hyenas in Africa today are capable of eating the entire carcass of a zebra, bones and all, but even they retain the carnassials to permit them to slice meat and other softer tissues.

Copied from M. Anton and A. Turner (1997). The Big Cats and their fossil relatives. New York: Columbia Univ. Press. I present it here in good faith to add to this discussion and educate my students and followers of this blog.  If the university or the authors wish I will gladly remove the quote in favor of a link to the information.

Turkey Tale

I came across a fantastic tracking scene while at work mentoring kids in Nature connection last week.  I would like to lay this whole thing out for you, really “geek out” on it and share what the kids observed.  I was lucky enough to be able to share this mystery with two groups, the one I found it with on Thursday and my advanced teen skills group on Friday.  The pictures and more in depth analysis took place Friday morning which is what I will share with you here.

Below is an area we walk through often, an access road on the edge of a small field with Red Cedars and Goldenrod overgrown with Mile a Minute Vine.  It’s in Newtown, CT.  We walk this every friday on the way to our camp.   If you look closely you may be able to see some feathers in the trail.  There was nothing the Friday prior.

 

Kill sight area.  Access road between cedar meadow and wooded hillside.
Kill sight area. Access road between cedar meadow and wooded hillside.

In the middle of the road we found these flight and body feathers of a Wild Turkey (below).  I did not let on what kind of bird it was.  Many in the younger Thursday group said the feathers were from a hawk, probably because of their size.  Some of the teenagers were very familiar with turkeys and ID’ed them immediately.  I challenged the teen-aged group to work together and then tell me individually the answer to the questions “who, what, where, when, why and how”.  Some of these kids have been mentored in Nature connection for many years.  All of them, including the newer students,  are sharp inquisitive people and I knew I was in for a fun time.

I will share our observations and conclusions and add some research I did later.  Put you nerd hats on ’cause we are going deep.

First scene of kill site, primary flight feathers and body feathers of Wild Turkey.
First scene of kill site, primary flight feathers and body feathers of Wild Turkey.

In the end we found three distinct scenes of sign, mostly feathers.   The first was on the road on the North end of the field, the next about 15 feet to the Southeast into the field and the third, 15 feet or so Northeast from the second, just on the North edge of the road.  This first scene included the above grouping of feathers in a radius of about 5 feet or so (being with the kids I was not able to get the best pictures or documentation).  This group contained a number of flight feathers (wing) and body feathers (above).  I have not yet determined which part of the body the smaller feathers are from.  The two pictures below show details of some of the sign.  This was obviously the site of predation, especially clear after finding that most of the feathers were “sheared.”  Many of the larger ones in two or more pieces.  The differing anatomy of predatory species lead to a difference in how they remove feathers to get at the meat.

Shorn primaries from first scene.  Note they are clipped in two places.
Shorn primaries from first scene. Note they are clipped in two places.
Body feather from first scene.
Body feather from first scene.

The second scene (below) still had some snow in it.  However the only tracks were melted out deer.

Second scene.
Second scene.
Secondary flights shorn and tail feathers plucked from second scene.
Secondary flights shorn and tail feathers plucked from second scene.

In this grouping where more sheared primaries and secondaries (wing feathers) and some plucked tail feathers (top of above photo).  Below you can see some damage from the plucking or an attempt to shear a nearby group of feathers.

Evidence of teeth being used to pluck this tail feather.
Evidence of teeth being used to pluck this tail feather.
Flight feathers shorn and plucked from second scene.
Flight feathers and one tail feather shorn and plucked from second scene.

Again there were many wing feathers and larger body feathers in this area of about 5 or 6 ft dia.  It also included tail feathers which the first scene only had one or two of.  Below we found the turkey’s beard. Occasionally females will have a beard, as far as I know adult males always do.

Turkey's beard at second scene.
Turkey’s beard at second scene.
Scat found in center of second scene.
Scat found in center of second scene.

There were no tracks on the snow, there was however this scat about half an inch in diameter full of fur.

Third scene.  Students observing feathers and bones from Wild Turkey likely killed and eaten by a Red Fox.
Third scene. Students observing feathers and bones from Wild Turkey.

The third and final scene seemed to be the dinner table.  The remaining wing feathers, just a few body feathers, and the larger bones picked clean.

Feathers and bones.
Feathers and bones.
Leg bones and pelvis cleaned of meat.
Leg bones and pelvis cleaned of meat.

Above is what is left of the upper leg bones attached to the pelvic girdle.  The femurs where both broken in the middle.   Other broken bones were scattered nearby.

Whats left of a talon.
Whats left of a talon.

Little was left of the feet.  Above is one of several talons we found at the third scene.  (Above)

(Below) Some scaly skin from a “shin” or lower leg.  I placed it on the stick for the photo.

Scales from foot of turkey. I put it on the stick to take the photo
Scales from foot of turkey. I put it on the stick to take the photo.

Interpretation:

Who?

The carcass was Wild Turkey.  Several of us are very familiar with their feathers and anatomy and I double checked with a feather ID guide.  Who was the culprit?  We suspect it was a Red Fox.  This ID is much more complicated.  I will break it down.

Could it have been an arial predator?  The sheared feathers indicate a mammalian predator, birds do not have the carnassial teeth required to cut and therefor must pluck.   Which mammal?  Bobcats have less developed carnassails than canine and would not have left such nicely cut quills.  Elbroch reports Red Fox and house cats often both shear and pluck, Red Fox often pluck the tail rather than cut them which is what we observed here.

The scat we found is consistent with Red, Grey Fox and Eastern Coyote.  It is close to the small end for Coyote and we do know there is a resident Red Fox.  Grey are rare in the area.  It is of course possible that the scat was placed later merely to mark the carcass as foxes will do.  However  it was the only scat in the area besides a green, hairy, mushy one I did not get a picture of, that was even smaller in diameter than the one pictured.  If a Coyote had killed and eaten the turkey I would have expected it to poop.  After all, everybody poops.

Where?

Where did the turkey come from? Where was it when it was attacked?  Where was the fox before the attack?  Where did the fox go after?

Not being an arial predator that attacked, the turkey could not have been flying at the time.  Could it have been in a tree roosting?  Some of the younger kids thought a bobcat could have climbed a tree to get it.  The older kids and I felt any turkey smart enough to make it to adulthood would wake up and fly off if something climbed up a tree it was in.  So the turkey must have been on the ground.   The fox may have been hidden nearby, possibly lying in wait as Wild Turkeys are notoriously hard to sneak up close to.

We found no tracks so could not determine much of the before and after.

When?

When did the attack occur?  I asked the kids when turkeys and fox are active.  Turkey roost at night, fox tend to lay low during the day.  They had noticed that there were no tracks in the snow yet the animal must have stepped there to leave the scat.   The snow had been soft enough for a portion of each day over the last week to allow for footprints.  So we postulate that the attack took place early in the day when the snow was still hard, less likely later when the snow might be softer from the day’s sun.   It couldn’t have been at night ’cause the bird would have been in a tree.

When did the scat arrive?  At some point a fox poops at the second scene.  It felt to me this would have happened after the food was gone.  Red Fox often leave a message to themselves not to bother with an empty food source.  Why no scat on the bones at the third scene?

Why?

Why was the turkey killed?  Easy, someone was hungry.  Why this turkey?  It was a male and may have been alone making an easier target.  A male is more likely to be alone and it would be extremely difficult for a ground predator to get the jump on a flock (or rafter as it turns out a group of turkeys is called).  Maybe the fox knew the routine or where it had roosted the night before and was waiting.  There was nothing indicating that the turkey was compromised by injury or disease though there was little left to examine.  If it was sick or injured, it would have been an easier target.

What and How?

We had many hypotheses.  One way we think it could have gone down is like this:  The fox gets lucky and jumps the turkey at scene one.  Fox pins turkey and starts chomping feathers.  Some pressure forces fox to move East to second scene and again to the third.  Either the turkey is not dead and runs or an outside disturbance is involved.  The fox eats the turkey down to the bones at the third scene leaving not a scrap.

What outside force?  We surmised that possibly the fox’s mate showed up.  This time of year fox are paired up either mating or preparing for kits to be born.  This may have caused the original fox to move around while dealing with the feathers, not wanting to share in its kill right away.    Also, it seems like a lot of meat to be consumed on the spot (it must have been since the bones were left at the third scene), which would also indicate the possible presence of a second animal because foxes will cache what they cannot eat and would have moved any leftovers to a more hidden location. If it were a mated pair, they may have eventually shared in the feast.

Conclusion.

Way too much fun!  Theories, guesses, conjecture, critical questioning.  One of the students found the second group of feathers and said “wait, why are there more over here?”  He was incredulous.  Good for him.  It was good for all of us.