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Purple Finch and Pine Siskin invasion

Posted on Nov 14, 2014

Two species have recently flooded the Northeast and Mid-Atlantic according to list serv reports, accounts from friends and my own personal observations – the Purple Finch and the Pine Siskin. The former has been unbelievably abundant in my experience, often being difficult to go outside for any length of time without seeing one in the past month. The latter, while a bit tougher to spot, has nonetheless zipped by in sizable groups and maintained their nomadic feeding habits. Just how massive are these irruptions in our region? I turned to eBird to find out the truth.

Here are both Purple Finch (orange) and Pine Siskin (green) graphs from eBird data in New York, Pennsylvania and Connecticut for all of 2014 as seen by week. The first is frequency which is defined as the percentage of all eBird checklists within the period reporting the species. Purple Finches have indeed been seen by many folks in mid to late October with Pine Siskins making a similarly huge jump considering the previous percentages were at or near 0.

PUFI PISI frequency eBird graph
Abundance is the average number of the birds seen on all checklists which tells us many more Pine Siskin individuals were seen overall.

PUFI PISI abundance eBird graph

Here is the average count, the number of each species seen when it is recorded. This provides more context on the bird numbers with Pine Siskins recorded in sizable flocks in the field and at feeders as opposed to the most commonly seen small groups or handful of individual Purple Finches.

PUFI PISI average count eBird graph

The birds per party hour is how many Purple Finches and Pine Siskins were spotted for each hour of birding with the former species being rather low because of the fact they were more frequently reported and, having smaller numbers overall, are spread throughout the time. Pine Siskins leap off the map having been encountered less but in the as previously mentioned higher numbers.

PUFI PISI birds per party hour eBird graph

The high count graph is the highest number of birds seen on one checklist entered into eBird during each week. In this case it looks like we can thank hawk watch sites for entering passerine counts as I do not think peaks of 1972 Pine Siskins or 1600 Purple Finch came from backyards…

PUFI PISI high count eBird graph
My personal observations seem to have been mostly in line with what others in the three states have seen, though I feel I spotted more Purple Finches than others have and fewer Pine Siskins. What about you? Having the global database that is eBird available to provide all of this information makes the research and study of these irruptions much easier. Instead of wondering if our anecdotal observations are true or false we have reports from around the United States, and the world, by citizen scientists like you to shed light on bird distribution, abundance, health and continuing movement. Sign up to use eBird today if you have not! There is no better time to start officially counting birds than on a cold and snowy weekend at your home.

Scott Kruitbosch
Conservation & Outreach Coordinator