The fledgling spotted and barred owl calls are precursors of the adult
whistle call. This can be seen as the season progresses and the young
owl's airy and hissy call begins to get some tonal quality. In fall, the
young owl's calls are a cross between the two, both hissy and some elements
of a whistle, eventually changing to a pure whistle. This is the only call
you will hear from the young until sometime in the fall when they begin to
attempt other calls.

The calls of the spotted and barred young are very close in sound. Unless
you have heard a lot of them, it is really impossible to tell the
difference, and even if you have heard many young owls, it is still
questionable. From my experience, the barred young tend to have a more
"metallic" edge to their call, particularly at the rising end of the call.

The best way (other than visual) to determine which species you might be
hearing is through additional clues. Barred owl young are generally more
advanced and will be louder than a spotted owl young at any point in the
season. As the season progresses, the barred will get some tonal quality
to their call earlier than the spotted.

At this time of year, barred owl young are more mobile - if the young are
actively flying around and calling from different locations, it is more
likely a barred owl. While the young spotted owls may also be mobile, they
are still tending to stay put until about this time of year, and let the
adult come to them or move short distances. About this time of year the
spotted owl young are also becoming more mobile, more so as the season
progresses, so this indicator is best applied in late June through July.

The great horned owl young's call is different in that it is louder than
the others and generally a flat call in comparison. Both the barred and
the spotted have a distinctive rise to their call at the end, becoming much
higher in pitch and louder. The great horned owl young's call stays about
the same pitch and loudness throughout. All of them become much more
insistent and louder when an adult is detected. Between the three at any
time through the summer, the great horned owl is the most mobile, then the
barred, and the spotted owl young is the least mobile.

Also, take note of the habitat. Great horned owls tend to be in more open
areas, barred owls are more associated with edge and water sources, spotted
owls with deeper forest. I have located both barred and great horned owl
young in both forest and opening, but of over 100 spotted owl young, they
have all been within the forest canopy. However, as always, there could be
exceptions.

At least one of the adults is usually nearby, until sometime late-summer or
early fall - if you can mimic the call of the spotted owl or the barred,
try a few calls and you may get the adult to respond. Or, if it is close
to dusk, the adults may become active and begin the night with some
spontaneous calling.

None of these are conclusive, though, and the only way to be sure is
through visual ID or association with adult birds.

It can be difficult to differentiate between the young and the adults at
his time of the year because they are now roughly the same size. The best
way to tell the difference between adults and young for spotted and barred
is to look for signs of down. Both species carry some semblance of down
through the summer and into early fall. Down is usually retained latest on
the belly and head, with the wings losing the down first.

Also, young owls are much more curious and will do a lot of head-bobbing
and head-circling to try and get an idea of what you may be. They will
generally focus intently on your presence while the adults will look away
more often, taking note of their surroundings.

Bob Pearson
Packwood, Washington
rpearson at i-link-2.net