Dec 022014
 

Of all the months on the calendar, November is the one that we can expect to see the most Barred Owls exposed and active in daylight on and south of the Canadian Shield in southern Ontario. I believe there are many contributing factors to this, and sometimes, they will all come together at once. And when they do, Barred Owls seem to be everywhere.

1) We do indeed have a healthy breeding population of Barred Owls in the Kawarthas, and especially on the Shield. By the time the leaves have fallen in mid-autumn, most locally-produced young have dispersed out of their parents’ breeding territories. So now, we have “more” of these owls around than we did before, (assuming that production of young owls during the previous nesting season was reasonably good). These younger owls are not so experienced, and through hunger alone, can sometimes be forced to hunt at dusk, and/or earlier in the afternoon and evening, (or during any time of the day, for that matter).

2) As is the case with all other raptors, there is an annual and roughly southward movement of young Barred Owls into and through this area from places further north, and so, even more Barred Owls will appear on the southern Shield, and southward at this time of year. If you are, (like I am), one who keeps up with the bird postings on the Ontbirds site, you will notice that nearly every fall, (and most often in November), that there is an influx of Barred Owls reported, from many southern locations from Toronto, Whitby, Brighton, eastward to Kingston and beyond, that have reached Lake Ontario.

3) It is also interesting to note that during years when reported Barred Owl sightings in southern Ontario in November are in higher-than-normal numbers, this usually, (more than 80% of the time), follows some of the largest catches of Saw-whet Owls during the same autumn season(s) at many of the banding stations that track their movements each October. (Although Barred Owls do use Saw-whet Owls as food when the opportunity presents, I am by no means suggesting that the former are “following” the latter into southern Ontario). Apart from voles, (which are used as food by all owls in Ontario), Deer Mice are important foods for both Saw-whet and Barred Owls, and it has been said in the past that when Deer Mice populations crash in the north, and in central Ontario, that these two owl species are recorded in the south in larger numbers in the fall and winter than they do during years when the mouse populations further north are more abundant and stable.

Something that I find of added interest to all of this, is that preceding each of the past three large irruptions of Great Gray Owls into southern Ontario (1995-96, 1996-97, and 2004-05) higher-than-normal numbers of Barred Owls were recorded in southern Ontario in November, and greater numbers of Saw-whet Owls were netted at banding stations in October of the same year(s). I will do a little digging, and find out from some of the owl banders that I know, and see if October of 2014 was in fact a bumper year in terms of large numbers of Saw-whets caught and banded in Ontario. How/if it may relate to Great Gray movements, (as it appears to have in the past), is unclear to me. But, if the past three large irruptions are somehow connected to earlier Barred and Saw-whet Owl movements, then maybe we`ll see some Great Grays later on in the coming winter this year. Perhaps there is no connection, just something that happens, and only looks somehow related.

It would be worth checking, (if the increase in Barred Owls continues in the coming weeks), how many are true adult birds, and how many are young of the year. This can be easily determined, (and I`ll try to post photos showing the differences later). If a Barred Owl is a youngster, generally, it will look not un-like any adult of its own kind. But, if you are viewing one at close range, and have a good pair of binoculars, a spotting scope, or a fine zoom on your camera, you can determine just about any first winter young Barred Owl, from an adult bird. It is important however, that you get a good view of either the back or one side of the owl, (and if you have not done this before, it may take some practise before it becomes routine for you).

First; most young Barred Owls are browner (and some, almost leaning towards “rusty”). Adults are most often decidedly grayer than the rich brown of the young ones. I am talking about the coloration of the head, neck, back, tops of the closed wings, and the upper surface of the tail. (Underparts show no difference among age groups to speak of). If the bird does have a rich brown, (or even rusty) look to the back as it is perched, just check what you can see of the secondary wing feathers and their greater coverts. If they appear to all be of an even tone, (with no feather appearing lighter or darker than the one next to it), then it shows that the bird has likely not ever moulted. Hence, a first year immature owl. If the bird seems grayer than browner, check those secondary wing feathers as above, and if you notice that in a random pattern, some are darker (indicating new feathers), while others are paler, (indicating older faded feathers) then your bird has moulted, and thus, is an adult, (or at very least, is a second year bird). The brown vs grayish coloring is not 100% reliable to determine the age of the bird, (as a few can be grayer in their first year, and there are some very brown adults out there), but it is reliable enough, that it is a good place to start. Most young are browner, and most adults are grayer,,,,, to put it simply.

Barred Owl with Winterberry in background - Tim Dyson

Barred Owl with Winterberry in background – Tim Dyson

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