A Wolf pack or Coyote family unit will howl in a chorus and use tonal modulation.............. The changes in the pitch of the howls(wolves)/yips(coyotes) makes it difficult to single out one individual wolf or coyote from the rest of the pack/family unit----especially if the pack/family unit is howling/yipping together...............This rapid tonal shift and combined howling/yipping makes a pair of wolves/coyotes sound like many more and is referred to as the BEAU GESTE EFFECT...............This "effect" has the result of making it hard to determine the size of a pack/family unit and is both a defense mechanism and a potentially lethal means of disguising numbers from rival packs/family units

Coyotes: Listening to Tricksters | The Outside Story

COYOTES: LISTENING TO TRICKSTERS

As the sunset colors fade from purple
 to black, the
 forest is dimly illuminated by a first 
quarter moon. 
An eerie sound breaks the calm. It is 
not the long, 
low, slow howling of wolves that can
 be heard further
 north, but the group yip-howl of 
coyotes: short howls
 that often rise and fall in pitch, 
punctuated with 
staccato yips, yaps, and barks.

When people hear coyote howls, 
they often 
mistakenly assume that they’re 
hearing a large
 pack of animals, all raising their
 voices at once.
  But this is an auditory illusion 
called the “beau
 geste” effect. Because of the 
variety of sounds
 produced by each coyote, and
 the way sound is
 distorted as it passes through 
the environment, 
two of these tricksters can sound
 like seven or 
eight animals.

Group yip-howls are produced 
by a mated and
 territorial pair of “alpha” coyotes,
 with the male
 howling while the female 
intersperses her yips, 
barks, and short howls. “Beta” 
coyotes (the
 children of the alpha pair from
 previous years)
 and current year pups may join
 in if they are
 nearby, or respond with howls 
of their own. 
 And once one group of coyotes 
starts howling,
 chances are that any other alpha
 pairs nearby
 will respond in kind, with chorus 
after chorus 
of group yip-howls rippling across
 the miles. 

I spent seven years studying coyote
 vocal 
communication during my dissertation 
research 
at the University of California, Berkeley.
 While
 eastern coyotes are a larger and distinct 
subspecies from the western coyotes that
 I
 worked with, the basic findings of my 
research
 and the work done by others applies to
 all coyotes.
  Coyotes have sometimes been called 
“song dogs,”
 and their long distance songs come in
 two basic types.

The first, the group yip-howl, is thought
 to have 
the dual purpose of promoting bonding 
within the
 family group while also serving as a 
territorial 
display. In other words, the coyotes
 are saying
 “we’re a happy family, and we own 
this turf so 
you better keep out.” In a sense, the
 group howls
 create an auditory fence around a 
territory, 
supplementing the physical scent 
marks left by
 the group.

Coyotes will also howl and bark
 separately. This 
second type of song is virtually 
always an 
indication of disturbance or
 agitation, and in
 my experience, the higher the
 proportion of 
howls, the more agitated the 
coyote is. Coyotes
 will howl and bark at neighbors
 who intrude
 on their territory, and at dogs,
 people, and other
 large animals that they perceive
 as a potential threat.

My research documented that 
coyote barks 
and howls are individually specific.
 Much like 
we can tell people apart by their 
voices, there 
is enough information in coyote 
vocalizations 
for me (OK, my computer if you 
want to get 
technical) to tell individuals apart. 
If, as I 
suspect, coyotes can distinguish 
each other
 by their song, it would not be 
analogous to 
the animals constantly shouting
 their own 
names; it would be more akin to
 our ability
 to recognize Marlon Brando
 because of the
 distinctive timbre and cadence
 of his voice.
 Characteristics including 
dominant pitch, 
duration, how quickly howls rise
 and fall in
 pitch, and tendency to “warble”
 while howling
 all distinguish one coyote from
 another.

For howls, this individual 
distinctiveness does 
not fade with distance. I was 
able to record 
and identify individual coyotes
 over a distance
 of greater than one mile. Given 
their keen hearing,
 it is likely coyotes can discern
 individual howls
 at much greater distances 
—three miles or more 
on a calm night.

Barks, on the other hand, degrade
 quickly over
 distance, with the higher frequencies
 fading first.
 This makes it theoretically possible
 for coyotes
 familiar with an individual (say, a 
mate or family
 group member) to determine 
roughly how far
 away that individual is, based 
on the proportion
 of high frequencies in the barks.

Imagine a scenario where a lone
 coyote is patrolling
 the territory boundary and comes
 across an intruder. 
He starts barking and howling, and
 his mate and 
beta children come running to the 
right place
 because his howls indicate how 
agitated he is, and
 his barks allow his family to pinpoint
 the direction 
and distance to his location. Although
 I was not able
 to prove that coyotes can do these 
tasks, the
 information needed is present in
 their calls and 
there are strong evolutionary 
advantages to learning
 how to use it.

We still have much to learn about 
coyote vocal 
communication. Even after years 
of studying 
coyote calls, I was barely able to
 scratch the
 surface. These tricksters hold their
 secrets tightly.
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Brian Mitchell is an adjunct professor
 at the
 University of Vermont. Now that he 
has kids,
 that grad school schedule of getting 
up at 2 
AM for field work sounds pretty relaxing.
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