Breeding Bird Atlas 1

northern harrier illustration

The Massachusetts Breeding Bird Atlas 1 project was a monumental effort to map the distribution of the breeding birds in the Commonwealth, and was the first of its kind in the United States. Results from this work were published in hardcopy in 2003, and presented detailed distribution maps from the 1974-1979 Breeding Bird Atlas 1 surveys. In preparation for our new Second Generation Breeding Bird Atlas Project, and to increase the accessibility to this information, we have prepared this online edition of Massachusetts Breeding Bird Atlas 1. We hope students of bird ecology and environmental conservation, land-use managers and planners, birders and all other wildlife enthusiasts will explore these maps and species accounts, and reflect on the changes we see in our State's bird distribution.

It is important to note that the online species accounts, and the data used to create the online maps, are identical to the hardcopy edition. However, those of you who have a hardcopy edition may notice a several changes between the hardcopy and online editions.

The most substantial difference between the two editions is the map presentation. To complete the online edition of Massachusetts Breeding Bird Atlas 1 we imported the original data into ESRI ArcMAP version 9.1. We created base maps using data layers provided by MassGIS, and with the generous support of Mass Audubon's Jeff Collins and Tom Lautzenheiser, we were able to create a base map that renders the outline of the sampled blocks, shaded relief, the Connecticut River and Quabbin Reservoir, state boundaries, neighboring states, and major highways in Massachusetts.

For the online edition we selected a new set of symbols to show the distribution of the state's breeding birds. All blocks were sampled during Atlas 1, and an empty block reveals that the species was not found in that block during the sample period. There is only one species map that renders different data in the online edition—the map for Chestnut-sided Warbler was incorrect in the hardcopy, and is corrected in the online edition.

The species accounts are presented in taxonomic order following the 7th AOU Checklist order. This will be a notable change for those of you familiar with the hardcopy edition, which followed the 6th AOU Checklist order. We anticipate that the official order will continue to change to reflect advances in our understanding of the taxonomic relationship of species, and we will update the order on this site to reflect major taxonomic changes.

While you are reading the species accounts it is important to remember that the data were collected from 1974 through 1979, that the species accounts were written in the 1980s and 1990s, and that the hardcopy edition was published in 2003. The species accounts do reflect notable range and status changes that occurred in the post-data collection period, but in some instances there have even been more changes since the species accounts were written in the 1980s or 1990s.

American bittern illustration

Another change between the two editions is that we abbreviated some sections in the front matter and back matter. Our goal was to shorten the online text, while retaining the most salient information. We did not edit any of the text in the species accounts, and all the illustrations are the same between the editions. If you have questions, we encourage you to consult the hardcover edition or contact us directly at birdatlas@massaudubon.org.

The hardcopy edition of Breeding Bird Atlas 1 has transparent overlays that can be placed over the distribution maps and correlate to regional elevation, county boundaries, quadrangle names, major drainages, ecoregions and forest types. The online technology does not yet allow us to present the overlays as layers of interactive maps, but we will continue to explore ways to bring that technology to these maps, and to the maps in the Second Generation Atlas.

Enjoy, explore and learn from the maps and species accounts that follow. Atlas 1 represents the work of over 600 volunteers, and presents a vital snapshot of the distribution of birds in Massachusetts in the mid- to late 1970s. Bird populations change quickly, more quickly than many of us thought. For those who doubt that this is true, please read Chan Robbins' Welcome, and, for a quick look at some probably increasing species, connect to the maps, and read the description of Wild Turkey and Red-tailed Hawk. Golden-winged Warbler, Pied-billed Grebe and American Bittern may tell us a different story, but that story will not be revealed until we finish our second Atlas surveys. But it will be this first data set that we use to compare and evaluate changes in bird populations—and for that, we offer our sincere thanks to everyone who designed, worked on, and completed the first Massachusetts Breeding Bird Atlas.