Hi,
(about a mystery owl at Cerise Creek, B.C.)
the ID of this owl is after consultation of CD's still open: either
Western Screch Owl or Boreal (or Hawk) Owl.
My impression of the call was: same pitch, very little lowered at the
end; intervals between single whistles almost equal, only little
acceleration.

...and I pass on Jack Bowling's description of the calls of the 2 owls:
> Well, a WSOW has two typical song types:
> 1) a series of rapid notes which break into a lower pitch halfway through;
> this is usually sung in duet between mated pairs with one of the pair's
> series overlapping that of the other.
>
> 2) the males territorial call which is the typical "bouncing ball" type call
> which is a single pitch series of 8-12 notes which accelerates through the
> series and then drops in pitch noticeably at the very end.
>
> A BOOW call is quite consistent through its range and consists of a series of
> 10-18 or so notes which if anything rise in pitch slightly at the beginning
> and then remain on the same pitch through the series. If anything, there is
> slight acceleration through the series. Many observers (including myself) get
> it mixed up with Common Snipe when first hearing it. However, it does not
> have the up and down variation in pitch typical of the winnowing of snipe.
>
> Admittedly, your description fits WSOW better than BOOW! May be worthwhile to
> pass this on to the Vancouver birding crowd to see if there is anyone able
> to check this out.

Reto Riesen
Dept.Chem.,UBC
Vancouver,B.C.
riesenr at chem.ubc.ca