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Blue Jays on the move?

Posted on Oct 6, 2014

Whether I have been in New York, Pennsylvania or Connecticut recently it feels like everywhere I turn I see a Blue Jay. Whether it’s one, two, several or more they are filling up every bit of land they can find. I mean this quite literally – every time I walk outside of RTPI it seems as if there are Blue Jays active all over the place. Considering the calendar it occurred to me that we are probably experiencing an influx of migrant Blue Jays.

Blue Jay (Cyanocitta cristata) Forest Road

Being such common backyard birds and a widely adaptable species it can be difficult to discern when a Blue Jay movement is taking place. We see them in all the same places, after all. Nevertheless I pay attention to such things because I am both a weather and a bird nerd. Thanks to eBird we have all the data we need to find the answers.

Let’s look at five graphs with Blue Jay data from New York, Pennsylvania and Connecticut for all of 2014 with data by week. The first is frequency which is defined as the percentage of all eBird checklists within the period reporting the species. Many more people have seen the species lately, huh? Nearly 70% of all birders in the three states saw a Blue Jay the last week of September! Thus far in October we are just under two-thirds. You can see the dramatic increase starting in mid-September below.

Blue Jay frequency

Abundance is the average number of Blue Jays seen on all checklists. Suffice it to say they are not only being encountered more frequently but also being seen in great numbers.

Blue Jay abundance

This is the average count, the number of Blue Jays seen when the species is recorded. This graph shows a nice curve for when they quiet themselves down and get busy with nesting season only to slowly climb as fledglings leave and migrants begin to pour in.

Blue Jay average count

The birds per party hour is how many Blue Jays were spotted for each hour of birding. This bump nearly matches the one seen in late winter which I would suppose is because birds were moving north once again and because it is such a difficult time of year to find food with many birds visiting feeders or foraging in other obvious ways.

Blue Jay birds per party hour

Here is the high count graph which means just that – the highest count of the species entered into eBird for each week. Holy cow! This exposes a lot of what I think is going on here in general in that Blue Jays are being tallied in strong numbers at hawk watch sites.

Blue Jay high count

Whether it is a yard or a count site it seems certain that we have a bunch of Blue Jays moving through our area right now. My anecdotal observations could never be confirmed or denied if not for data like this provided to eBird by citizen scientists like you. If you have not contributed please sign-up as a new eBirder today and help add to the power of this global database.

All of this matches the expected flight predicted by Ron Pittaway in the 2014-2015 Winter Finch Forecast which said, “Expect a good to heavy flight (many more than last year) moving westward along the north shorelines of Lakes Ontario and Erie because the acorn, beechnut, hazelnut and soft mast crops averaged low in northeastern, central and eastern Ontario.” Have fun with the Blue Jays in your yard. We will have to see how many push through and how many remain all winter…

Scott Kruitbosch
Conservation & Outreach Coordinator