My current cat does this and my previous one did also.

From what I understand, it's an exhibition of frustration over not being
able to get at the prey.

Judy

Yep, it is common practice for some cats, they almost seem to talk.

Squirrel

If homosexuality is a sickness, then I am going to start calling in queer to work.

My 2 girls "talk" to the birds when they're sitting in the window.  It's
pretty cute!!  :)

Shannon

According to the cat book this is absolutely normal behaviour, I myself have
never been able to watch it though.

Carola

Pudge did this in her younger days. Hodge doesn't do it as much because
he's figured out he's never going to get those darn birds. But when we
first moved here, I thought he was going to break some windows . . .

My Stella does this... kind of a half meow half chirp. Sometimes its longer
an and almost stuttered but it's amusing nonetheless.

Adam Helberg skrev:

Several of the cats I've had over the years have made funny, almost
clicking noises with the same jaws movements you describe, every time
they've seen a bird outside the window.
As far as I can tell, it expresses the frustration of seeing a possible
prey without being able to get at it.

Niels Peter
www.bluewhite.dk

All mine have done that.

W

Many cats do this.  My currents cats just cry in frustration.  However, my
previous cat - Tiggypuss - used to chirp and 'chatter' with his teeth while
his tail swished. The tail-swishing is awareness mixed with pure annoyment;
the chattering chirp is actually a 'practice run' for the killing bite which
kitty would use if only he/she could get at the bird.  (The killing bite is
usually in the neck, so that the bird is swiftly subdued, thus avoiding
injury from the beak).

Spider

 Yes  -- TuTu does it all the time.   MLB

Both of ours do this. The exception is that the older and much bigger,
(18lbs worth of cat muscle), does it only when he wants to play. The younger
and smaller female, chirps at the yard rats, (Squirrels), any bird, and
roaming male cats, from her favorite window perch. She also does this to the
bulldog we have in an outside kennel. Drives him into a frenzy of barking
and snarling. Recently, she's taken to chirping at the wife's gerbils and at
the imitation mouse toys we found at Petsmart. Did I mention that shes all
light gray, but apparently touched with a bit of blonde somewhere in
her..;-)

Syrano...

Cute, indeed as perceived by a human :-)  Not so cute for the birds...  Your
kitty is getting warmed up to pounce on the bird and deliver the death blow.
The twitching tail is a sign that kitty is building up to an explosive
pounce.  The movement of the jaw is your kitty warming up the mouth muscles
in preparation for snapping the birds neck.  It is typical kitty behavior.
Though, some kitties will do this, and not attack the bird even if they
could.  It is just a strong instinct.  If you have ever seen you kitty eat
dry food, sometimes they will shake their head real fast when eating.  This
is another feeding instinct.  The shake their head real fast to strip meat
off the bone.  Even if there is no bone, like when eating dry food,  they
still shake their head while eating.  Kitty has been honed by nature to be
an ideal land predator.  They exhibit instinctual behavior constantly.
Including, the ritual you have noticed that your kitty goes through when
he/she sees birds.

Michael

Sitting at the window all day chattering the birds is an important release
for a cat :)

Cat Mog.

http://mogular.blogspot.com/