After eagerly awaiting the arrival of my copy of the "Atlas of the Breeding Birds of Ontario 2001-2005" for a few weeks, I was excited to find it sitting on my doorstep yesterday afternoon. From the stunning cover photograph of Prairie Warbler to the extensive content inside, the book quickly proved that it was well worth the wait. In fact, I think this new Ontario Atlas is the finest breeding bird atlas that I have ever seen.
Rather than providing an extensive review of the entire Atlas, however, I'm going to instead focus on it from a Boreal perspective. It goes without saying that this work is a "must have" for anybody interested in Ontario ornithology, but I also think that the Atlas is an invaluable book for all who are interested in Boreal birds. On the most fundamental level, the Atlas is a tremendous resource in answering the question, "What birds are Boreal birds?" I think most birders could quickly name several Boreal species, such as Boreal Chickadee, Gray Jay, Spruce Grouse, Black-backed Woodpecker, and Cape May Warbler, but how many of us would think of Red-eyed Vireo or Chipping Sparrow as being Boreal birds? And yet, in a table ranking the ten most common species for each of Ontario's five Atlas regions, both Chipping Sparrow and Red-eyed Vireo are in the Top 10 list for the Northern Shield, one of two Atlas regions (together with the Hudson Bay Lowlands) found within Ontario's Boreal Forest Region. Likewise, a table showing the species with the highest probability of being observed in each of the five Atlas regions lists a single woodpecker for the Northern Shield region. That woodpecker, perhaps surprisingly to many, is not Black-backed Woodpecker, but rather Northern Flicker. The lesson is that the term "Boreal bird" includes both species that are largely restricted to the Boreal Forest Region and more common, widespread species that include the Boreal Forest within their extensive breeding ranges.
These lists in the introductory pages of the Atlas provide interesting food for thought, but the real heart of the book is the individual species accounts. Each written account contains sections on Distribution and Population Status, Breeding Biology, and Abundance in Ontario. In addition, the species accounts contain different combinations of Breeding Evidence maps and Relative Abundance maps depending on the given species. The abundance maps in particular are excellent resources for learning not only where a species is found, but also where that species is found in large numbers. Yellow-rumped Warbler is a widespread breeder throughout much of Ontario, and the largest maps in its account are of Southern Ontario, where its range is expanding southward. But, a small abundance map for the entire province puts this southern breeding in perspective, visually illustrating how common the species is in different regions of Ontario. This species is most abundant in the Boreal Forest of northwestern Ontario, where Atlasers detected 15-24 Yellow-rumps per 25 survey points, as compared to 0-3 birds for the same number of survey points in the southern part of the province.
Another useful tool in the species accounts is the Probability of Observation bar chart, which shows the likelihood that a species was detected in a surveyed block in each of the five different Atlas regions. The case of the Bay-breasted Warbler provides a nice example of the utility of these charts. The Breeding Evidence maps show clusters of Bay-breasted records in the Southern Shield of Southern Ontario, which lies south of the Boreal Forest Region, and then scattered records throughout the Northern Shield, which is in the Boreal Forest Region. From a visual standpoint, a reader might think that the species is about equally common in the Northern and Southern Shields, but this appearance reflects not the species' true abundance, but rather the fact that the Southern Shield received much better Atlas coverage than the Northern Shield. A quick look at the Probability of Observation chart, however, clearly shows that Bay-breasted Warbler is much more common in the Northern Shield—it had a 53% probability of being observed in blocks in this area, and only a 14% chance of being detected in Southern Shield blocks. Cross-referencing the Relative Abundance map confirms that Bay-breasted hotspots are found across Ontario's Northern Shield.
Not only is the Ontario Atlas a valuable tool for those interested in learning more about Boreal birds, it should also be an incredibly useful resource for bird conservationists working to protect these birds. For most Boreal species, even basic information about their populations is limited due to the largely remote nature of the Boreal Forest. Questions such as "What is the breeding range of this species?", "How large is its population?", and "Where is it most common?" do not necessarily have good answers in many cases. In addition to the maps described above, the Ontario Atlas also includes an appendix with population size estimates for Ontario birds; together, these resources make the birds of Ontario's Boreal Forest the best-understood Boreal birds in North America. The Relative Abundance maps, for example, are an important first step in eliminating an "ornithological black hole," which is a lack of bird abundance information across most of the Boreal Forest region. The Breeding Bird Survey (BBS) provides this sort of information for most of North America, but BBS coverage largely ends near the southern edge of the Boreal. For northern-breeding birds such as Fox Sparrow, this means that the BBS might have limited or no data for the species. In fact, the BBS Summer Distribution Map for Fox Sparrow for 1994 to 2003 does not even show the species breeding in Ontario. The Ontario Atlas account, meanwhile, shows this large sparrow breeding across the northern half of the province, with especially high numbers of individuals in the northern part of Ontario's Boreal Forest Region. The Atlas also estimates the provincial population at 300,000 individuals, all occurring in the Boreal Forest Region.
The abundance maps in the new Ontario Atlas should serve as important tools as conservationists work to protect bird populations in the province. Without knowing where a species is common, it is very difficult to make informed conservation decisions to protect that species. Similarly, the population estimates provided by the Ontario Atlas will undoubtedly help bird conservationists to better assess conservation priorities, especially among Boreal birds. As an example, the Ontario Atlas provides a provincial population estimate of 6 million individuals for Yellow-bellied Flycatcher, which breeds across Canada from Yukon to Newfoundland, and also occurs in extreme northern areas of the eastern U.S. This estimate of 6 million Yellow-bellied Flycatchers just in Ontario equals the global population estimate for the species in the Partners in Flight North American Landbird Conservation Plan, which provides population estimates for all North American landbirds. While the Ontario population estimates are described as "rough ballpark figures," they should still be helpful in reassessing the population sizes of northern species like Yellow-bellied Flycatcher.
The "Atlas of the Breeding Birds of Ontario 2001-2005" is an outstanding achievement that is the fitting culmination of more than eight years of planning, field work, data analysis, mapping, and writing. I highly recommend it to anybody interested in Ontario ornithology or the birds of the Boreal Forest region.
The "Atlas of the Breeding Birds of Ontario 2001-2005" can be ordered on-line at the Ontario Nature web site, or via phone at 1-416-444-8419 ext 230. If you are calling from the United States, you should use this number for ordering, rather than the toll-free number (1-800-440-2366) that is provided on the Atlas web site and the Ontario Nature web site.
--Matt Medler
