Saw-whets make a great variety of calls. The more common ones are:

1) endless series of whistled toots (aka "advertising call"). Males in
early spring will do this for hours on end - often it's the first clue
people have that Saw-whets are in an area.

The other calls you will most likely hear only if you do playback to owls,
or if you visit an active nest:

2) Loud, high-pitched staccato barks: "Kew-kew!" "Kew-kew-kew!" Very
startling.

3) Nasal whines, sometimes repeated 20 or more times.

4) High pitched chittering.

5) Very high thin "seeet" or "tssst," like the alarm calls of some small
passerines. This call is apparently given only by female Saw-whets.

The account of hissy noises from a largish group of Saw-whets on Sucia Is
(sorry, I forget who posted that) sounds like begging sounds of young
Saw-whets. Most fledgling owls (including Screech and Barred, for
instance) have hissy, scratchy begging calls. Great Horned Owls begging
calls, however, sound more like a godawful screech :)

As to which of these calls is the "saw-whetting call," opinions vary, and
at least three of the above have been nominated. Historical accounts
suggest that the name originally came from #1, above. For instance, there
is a passage in Thoreau's "The Maine Woods" where Thoreau actually
mistakes a calling owl for a saw being sharpened; the call in question
seems to be the clear toots. A file ringing rythmically on the teeth of a
large crosscut saw might well sound more bell-like than harsh or scratchy.
The current confusion probably has something to do with the fact
that nobody today really knows what "saw-whetting" sounds like - any
professional saw-sharpeners out there want to help us out?

When doing playback surveys for Saw-whets in winter, I found that only
about half of the responding owls give the familiar "toot," or "truck
backing up" ;) call. Whines are just as common a response, and chitters
and kews are also fairly common. In the early breeding season, though,
it's toots, toots, and more toots.

Richard Cannings's Saw-whet Owl account in the Birds of North America
series has an excellent description of the vocal repertoire.

Chris Hill
Everett, WA
cehill at u.washington.edu