Barred Owl Barometrics

Owls are a favourite bird of many people, even non-birders. So when a Barred Owl showed up at Rondeau Provincial Park this past December, and has been seen intermittently as recently as yesterday, it is special. This bird is only the fifth known record for the Rondeau checklist area.

There is lots of suitable habitat for Barred Owl at Rondeau, and that begs the question as to why it is so rare. Of course looking at the very limited habitat across much of southwestern Ontario, there aren't many habitat linkages so birds from the species' normal range choosing the best habitat available to them would not be tempted to move into the Rondeau area.

But that may be changing, and not just because the amount of forested habitat here in the southwest is increasing to any extent. For some reason, Barred Owls have been recorded a lot more this winter than usual. It was interesting to read the various Christmas Bird Count reports for this past Dec 15-Jan 5 period to see where these owls were recorded more frequently than usual. Many counts only record them very infrequently if at all, so getting even one was a highlight. Some CBCs had them in record numbers. Okay, usually a single bird was a normal number reported in previous counts, but some counts were reporting as many as 3 birds. The summary reports provided by the count compilers on Ontbirds often made special mention of the presence of Barred Owl on their count.

I did a bit of search on eBird. This first map shows the Barred Owl reports on eBird during the three month period of December 2005 to February 2006 period. The purple rectangles indicate where one or more reports of Barred Owl occurred during that time. The darker the purple, the more reports within that rectangle.

Obviously there were very few reports during that period. However since eBird only got up and running in 2002, lots of birders had not begun participating, so it is not surprising how few records show up. In fact the grey rectangles indicate where there was at least one report of any bird species made, and the non-grey and non-purple rectangles indicate where there were no reports of any birds. There are probably as many rectangles without any birds as with at least one bird, and clearly Barred Owls were very limited.

This next map shows a similar area for the period of Dec 2010 to Feb 2011. Obviously the number of birders participating in eBird seems to have increased, given the increased number of grey and purple rectangles. And the number of purple rectangles has also increased. But the level of participation by birders entering data on eBird was still building, and it is not nearly at the same level as it is today.

This next map shows the period of Dec 2017 to Feb 2018, just a little over a year ago. The number of grey rectangles has increased quite a bit, as have the number of purple rectangles. It is interesting to note that across the border to the southeast of southwestern Ontario, it seems that the increase in purple rectangles is even greater.

Fast forward to the most recent three month period of Dec 2018 to Feb 2019. While the number of rectangles where bird data has been entered is much the same as the previous year, there is definitely an increase in the number of purple rectangles, including more darker purple ones.

As expected, the level of bird data entry on eBird continues to grow. It will be interesting to see what next year's map will look like. Will the species continue to appear to expand? Will there be a retraction?

The area shown on these maps is not the only area where Barred Owls have apparently increased. A recent news report from Nova Scotia, shown here, indicates the species has increased there as well. It has perhaps been a trend throughout the northeast, and the question is why. Has the weather been a factor, or the food available during the breeding season, causing a greater production of young, but during the winter the food availability is not enough to sustain the increased population so birds have to move beyond their normal range? This has certainly been the case for some other owl species, such as Snowy Owl. It is interesting to speculate, but for the time being we can enjoy the presence of this impressive owl.

Another thought to consider: maybe there is more than one Barred Owl in the Rondeau area. There certainly is enough habitat. As the mating season arrives, we will have to get out in the evening and listen for calling birds. Just maybe there is a pair of them and seeing more of this species is in our immediate future!