Alvaro Jaramillo wrote:

`snip`

> one of the 3 or 4 owls reported from the greater tweeters area could have
> been watched for a day or two to address how successful these birds were in
> hunting we could have learnt something useful. With adequate sampling and a
> concerted effort to identify the prey species as well as searches for
> pellets we could have estimated the daily intake of food. The energy value
> of this food could have been calculated using values from the literature and
> we could have arrived at a reasonable assessment of whether these owls were
> eating enough to stay alive or not. Sure, 3 or 4 is not a lot, but it
> probably would tell us more than one single radio tracked owl, however, its
> a little more boring and monotonous.


I appreciated the comments made by Alvaro, good food for thought.

Here in mid-Vancouver Island, we had a month-long visit by a Great Gray
Owl during the winter of 93/94. It was seen to be successful at catching
rats and/or voles on many occasions. According to my notes, the bird
could be found on average, once every second day. During the days that
it was seen, it was hunting, otherwise, it was roosting or simply could
not be found. It was my impression that the bird was able to feed and
that it would survive. After performing a search of the 'hunting patch',
I was unable to find any pellets. This may not be significant because,
as mentioned above, the roosting site (where pellets are more likely
found) was not the same location as the 'hunting site'.

--
Cheers,

Don Cecile
Port Alberni, B.C. Canada
dcecile at cln.etc.bc.ca.