Having re-read ward creation other than having a magic stat I can find no other requirement for creating wards.
Both spell slingers and conjurers can make wards obviously. Mystic adepts also a check.

But can any adept?

Is it simply a matter of paradigm?

Yes, adepts can create wards.

Being able to astrally perceive is also required.

But yes, this means that adepts can create wards, as long as they somehow learn astral perception.
As well as spirits or even dual-natured paracritters.
Or cyberzombies.

I'm particularly fond of wards created by bound spirits.
The method of fooling a ward by mimicking the aura of it's creator is so much harder when said creator is a bound spirit who is sitting within the ward all the time.

Edit : damn, i keep missing these small SR3 icons next to some threads.
Ignore what i just said, it's all about 4th ed and i've got no idea how much of it is correct in 3rd ed.
The thing about cyberzombies is certainly not true under 3rd edition rules.

Thank you AH.
I was tempted to break out the AH sign but your clearly on the ball.

This is an interesting idea that I hadn't thought of before. Do you think that non-sapient paracritters would instinctively build wards to protect their lairs and such? If so, sewers full of devil rats might have little wards all over the place. Might make for some interesting fluff.

Indeed, even though the fluff mentioned in Street Magic suggests that setting up a ward requires some rituals, such as painting protective signs on the walls and so on.
Also, warding in the traditional sense requires a certain degree of abstract reasoning, as you have to understand that astral threats may arise in the first place.

But i wouldn't completely rule out the possibility that some non-sapient critters instinctively ward their lairs to some degree.
The description of warding in the SR4 BBB doesn't mention the Sapience power as a prerequisite.
Of course, if that is possible, these wards would have something makeshift and unsophisticated about them (they couldn't be above Force 1 anyway), but the idea seems interesting.

I wonder what some barghests' ritual would sound like.

The force is limited to double its creator's magic, which is 3 or 4 for most critters listed in the SR4 book. I can't picture non-sapient critters sitting around for hours setting one up though.

More fun would be to have a roaming pack of dual-natured critters press through (or even defeat) your PC's ward - if they put one in a likely location. Does the abandoned warehouse they chose to hole up in happen to have a hole in the wall somewhere?

I tend to have insect spirit hives be dual natured with this line of thinking.

Um.. aren't they already? I thought all inhabitations were dual natured....

The physical place being warded not the individuals within them.

You can do some cool stuff with SR3 wards. I always liked warded armor. (My GM didn't. Spoilsport )