I hate to jump to conclusions, but I think trapping nearly 13,000 deer flies last season has made a big impact on reducing the deer fly population on our property this season. I'm not sure what else to attribute this great reduction in deer fly numbers to. We've had plenty of rain this season. Nothing has changed on our property or in the surrounding areas. I'm walking the same areas for the same amount of time for each trapping session as I did last season. There is just nothing else that I can think of which could be responsible for these low deer fly numbers this year. In fact, we continue to see very few dragon flies this year, which I would have thought would have resulted in higher deer fly numbers.
So, again, while wanting to not jump to any conclusions before all the data is in and before other explanations are considered, as of now I can't help but restate my opinion that my trapping of nearly 13,000 deer flies last season has made a big impact on reducing the deer fly population on our property this season!!
Here's a look at my 2013 trapping data thus far. Notice that this season I did not start trapping deer flies until the 23rd day of the season ... the season started on June 16 with my first sighting, and I didn't conduct my first trapping session until July 8 because there just didn't seem to be enough deer flies to justify going out to trap them. (I am slightly regretting not having gone out to start trapping earlier in the season because now I've allowed those few deer flies time to breed. Oh well, next year I'll start trapping even when there are only a very few deer flies around.) Due to my schedule and to morning rains, I was not able to go out trapping every day after I first started, but then I became consistent.
OK, here are the numbers for this season so far:
Now let's compare that to last season's data. This first chart compares the data from 2012 (in red) to the data collected thus far during 2013 (in blue). These data have been aligned by date.
However, the 2012 deer fly season started 15 days earlier (first sighting was June 1, 2012) than the 2013 season (first sighting was June 16, 2013). [Remember, 2012 was the year where spring came very early and was very warm.] Therefore, another way (and probably the correct way) to compare the data from these two seasons is to align them based on the point of the season (not the actual dates).
Here, then, is a comparison of last year's data to the data collected thus far this year, this time aligned with respect to the point of the season (i.e., days into the season, with day 1 being defined as the day of my first sighting for each season).
Rather interesting, don't you think? Seems that trapping does indeed cause a significant reduction of the next year's population of deer flies!
So how is your deer fly season going? Are the number of deer flies you are seeing this year significantly different than what you've experienced other years, or is this season fairly typical for you? I am very interested in what other observers (and, especially, trappers) in Livingston County, Michigan, and neighboring areas have noticed this year with respect to deer fly numbers.
I will post again when I have data collected for the remainder of the 2013 deer fly season. In the meantime, happy trapping!
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