Armed with maps and enthusiasm, birders spread out across the state in recent years to get some of the most detailed information available on avian nesting in Pennsylvania. The results of those efforts: the Second Atlas of Breeding Birds in Pennsylvania.
The 616-page book, published in November 2012, gives experts and novices a look at the nearly 200 species of birds that breed in Pennsylvania, from the well-known song sparrow to the merlin, which, for the first time, was documented as nesting in the commonwealth.
Researchers from Penn State, including the Earth and Environmental Systems Institute, were part of the efforts that brought together specialists from the Pennsylvania Game Commission, Cornell University and the Pennsylvania State Data Center, along with two dozen professionals who stopped at 36,000 points and more than 2,000 volunteers.
From 2004 to 2009, those bird lovers headed out across the state to listen for, identify and observe pileated woodpeckers, indigo buntings, robins and owls — 190 species in total. The state is divided into 83 regions, which are then further divided for volunteers who headed out into forests and meadows, listening and looking for birds and tell-tale signs that they were setting up homes, if only for a short while.
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Joe Bishop, geospatial coordinator at Riparia in Penn State’s College of Earth and Mineral Sciences, said the book includes bird reports with different levels of evidence of nesting from observation (the species is seen during breeding season) to confirmed (sightings of fledglings). In between those levels are possible and probable.
“There are protocols they follow to be sure it’s a breeding activity and not just a casual fly-by,” Bishop said.
Bird behavior, such as carrying nesting material in their beaks or a male singing in the morning, can be signs. “He might be flying around the perimeter of an area singing, trying to lure a female in, saying ‘Hey, I’ve got territory over here, let’s breed,’ ” Bishop said.
While the second edition of the atlas follows many of the practices used in the first, published about 20 years ago, it also breaks new ground. Bishop noted that the second edition has maps showing where the birds were found the first time, where they were seen this time and how that has changed.
“The most innovative aspect is the ability to report on the abundance of a species, versus just its presence or absence,” Bishop said.
To do that, an experienced team of birders went on “mini-routes,” designed with help from Riparia, part of the College of Earth and Mineral Sciences.
That data, combined with modeling led by Andy Wilson, a graduate student at Penn State at the time and one of the atlas editors, means that the second atlas has not only whether certain species are present in an area, but to what extent.
Bob Mulvihill, statewide project coordinator and an atlas editor, said that analysis means that instead of just saying that a bird is abundant, in many cases the data collection combined with statistical analysis enabled the researchers to provide a specific number. For the song sparrow: 1,990,000 males in the state.
“This allows us to interpret the behavior of breeding birds in Pennsylvania in a way no other atlas has been able to do,” Mulvihill said.
Knowing where in the state birds are breeding also means the “most bang for your buck” Mulvihill said. For example, researchers can look at the map and see where a species of high concern is most abundant and focus efforts there.
Data from the Pennsylvania Spatial Data Access center “made our effort rather trailblazing in some respects,” Mulvihill said.
“They gave us some really useful and cutting-edge tools that gave rank and file volunteers access to spacial data, GIS (geographic information systems) data, to enhance their ability to locate birds within the atlas survey blocks.”
Along with detailed data and maps, the atlas has beautiful photographs and chapters providing context and information about avian behavior.
Dan Brauning, project director, said the findings corroborate much of what was suspected. For example, grassland bird communities are in a massive decline, while forested birds “more than held their own and actually expanded their reach.”
So, if you suspect that you’ve been seeing more of the vibrant pileated woodpecker turning tree bark into sawdust, you might be right. Brauning said a hypothesis is that during the 20-year period between the two atlases there was extensive reforestation in Pennsylvania.
The horned lark, he said, disappeared from the western part of the state, but is showing up in the east.
“Each species has its own story,” said Brauning, who also edited the first atlas and is supervisor of the state Game Commission’s Wildlife Diversity Program.
Bernd Haupt, a senior researcher at EESI, compiled data on average temperatures and precipitation and changes using Department of Meteorology data from 123 weather stations from across the state for the second chapter, “The Geography of Pennsylvania.”
“Being part of a project that not only has real research value, but also has resulted in the publication of a book that can be used by anyone — from K-12 teachers in the classroom to scientific researchers to people who just love birds — is a really meaningful experience,” Haupt said.
“One of my questions was when are we going to start working on the third PBBA?” he said.
The answer, according to Mulvihill, is 2024.
In the meantime, while the atlas itself, published by Penn State University Press, has been completed, insights from it are expected to continue. The Center for Environmental Informatics, part of EESI at Penn State, is developing a website to go with it. That is slated to be online this fall. And, work by avian aficionados continues.
“The book is the first cut of what is possible to learn from the data,” Mulvihill said. “There is a goldmine of information about the songbird population and the relationship between birds and habitat in Pennsylvania.”