Sightings up of numerous Pennsylvania bird species
While there were lots of reports of fewer birds being sighted in Pennsylvania during the late fall and early summer, there are other species that are being spotted more frequently than usual.
State College birder Joe Gyekis analyzed bird-sighting data from the last two months of 2021 and compared it to the same period during the previous five years. These weren’t just personal sightings. Gyekis used the eBird data base, which is compiled by Cornell University’s Lab of Ornithology.
Cornell’s eBird collects bird lists from hundreds of thousands of birders around the world and thousands of Pennsylvania birders. The data is available for anyone to view and it is often used for research.
Birders record the species that they can identify on a particular outing, or while watching their bird feeders. They also record the number of each species, distance traveled and the time spent birding. This is done using the free eBird app on a cell phone or computer.
“I’ve been trying to find if there are birds that are showing up at higher or lower frequency last fall and early winter than during the past years,” Gyekis said.
The eBird bar chart data is divided into four blocks for each month. One block for each week for the first three weeks of a month and then the remainder of the month (7 to 10 days) is counted as the final week. What is reported is the frequency of bird lists with a sighting of that particular species, rather than the total number of birds for each week.
“For the first pass of data analysis, I decided to only look at species that were reported in at least 2.5% of the checklists statewide for at least one week of the November-December period,” Gyekis said. He further limited his data analysis to only species that had significantly higher or lower sightings during November and December.
And the winners are … robin, hermit thrush, yellow-rumped warbler, yellow-bellied sapsucker, eastern bluebird, eastern towhee, ruby-crowned kinglet, belted kingfisher, white-throated sparrow and brown creeper. All of these birds showed a higher frequency of reporting, with robins, hermit thrushes, yellow-bellied sapsuckers, bluebirds and b aboverown creepers showing very high gains. None were more dramatic than the hermit thrush. Their sightings were much higher last November-December than any of the previous five years.
The reason for the increased frequency of sightings could be many factors or a combination of several. It could be the warmer-than-usual November and December, less snow, or a higher amount of available food. Or it could be those species experienced a higher than average reproduction rate this past year.