The Development of Digital Atlas Maps of the Birds Breeding in Ontario
Background
Large-scale spatial analysis is required for many conservation
and ecological studies. This information is most useful in a digital
form. The Canadian Wildlife Service - Ontario Region, Environment
Canada, and the Landscape Analysis and Applications Section of the
Canadian Forest Service, Natural Resources Canada, together with
the Geomatics Unit - Ontario Region, Environment Canada, have compiled
the set of digital maps for the nearly 300 species of birds breeding
in Ontario, which are now available in WILDSPACETM on
the web. The information used to prepare these digital maps was
modified from the data used to produce the original set of maps
showing the distribution of birds breeding in the province published
in the "Atlas of the Breeding Birds of Ontario"
(Cadman et al. 1987). The Atlas was the culmination
of the volunteer-based Ontario Breeding Bird Atlas Project undertaken
during the period 1981 through 1985. These digital maps show where
the birds occur in Ontario, and indicate whether or not the species
is widespread or local, common or rare. Atlas maps are dynamic,
however, both because species nesting ranges are dynamic over long
time periods and because new data are continuously becoming available
that improve our knowledge about the breeding distribution of these
species in the province.
"The Canadian Wildlife Service - Ontario Region
acknowledges that not all species' atlas maps presented here are
completely accurate."
The Ontario Breeding Bird Atlas Project
The first of its kind in Canada, the "Atlas
of the Breeding Birds of Ontario" provides a picture
of the distribution of the province's nearly 300 species of nesting
birds during the early 1980s. The avifauna of the province is rich
and varied, including 75% of the bird species in Canada. The project
was made possible through the great cooperative effort of the Federation
of Ontario Naturalists (FON), the Long Point Bird Observatory (LPBO),
the Canadian Wildlife Service and the Ontario Ministry of Natural
Resources, as well as the many volunteer naturalists and regional
coordinators involved. The degree of precision of the survey was
possible because of the 180,000 hours of field work undertaken by
over 1300 volunteers from 1981 through 1985. To achieve the project's
goals, Ontario was divided into a grid and volunteer naturalists
were encouraged to visit every grid unit and collect information
on the birds breeding there. Working on foot, by car and bicycle,
from boats and canoes, by plane and helicopter, volunteers combed
every corner of Ontario to provide the 400,000 records upon which
the digital Atlas Maps are based. Also included were data collected
on some of the islands under the jurisdiction of the Northwest Territories
in James and Hudson Bays (notably Akimiski Island).
Methods
The data collection units for the Ontario Breeding Bird Atlas project were based on the Universal Transverse Mercator (UTM) grid system. The province was divided into a southern sector which was mapped and surveyed by 10 km squares, and a northern sector atlassed by 100 km blocks. The goal of the project was to attain at least a prescribed minimum degree of coverage in each square (10 x 10 km cell) and block. To ensure good coverage, an atlasser was required to visit all habitat types within the survey area, and was encouraged to visit the square throughout the breeding season to ensure that early and late nesters were not missed, and during the non-breeding period to find used nests when the leaves were off the trees. The breeding season for most species in Ontario is concentrated from late May through July, so most field work was undertaken during that period. Coverage, as measured by hours of field work in each square and block, however, was not spread evenly across the province. Most atlassers reside in and around large urban centres in southern Ontario, so coverage was most concentrated in those areas. In the road- or rail-accessible northern blocks, coverage was generally more comprehensive than in remote blocks. Naturally, the pattern of species richness observed was closely tied to the biogeography of Ontario, but the lack of coverage in some areas may have underrepresented the true number of species present.
There were 16 categories of breeding evidence, which were combined into 3 levels, with an additional category for birds simply observed in the breeding season with no evidence of breeding. These 4 levels, namely species observed, and possible, probable and confirmed breeding, are summarized as follows:
| Not Observed |
|
| Possible Breeding |
- species observed in its breeding season in suitable nesting habitat or single male(s) present or breeding calls heard
|
| Probable Breeding |
- pair observed in suitable nesting habitat in nesting season, often exhibiting territorial behaviour (song, etc.), courtship or other interaction displays
|
| Confirmed
Breeding |
- direct evidence of a breeding attempt such as used nest or egg shells, recently fledged or downy young, adults carrying faecal sacs or food for young (leaving or entering nest sites), nest with eggs or young
|
Atlassers were advised to spend the early part of the breeding season concentrating
on recording all species present in breeding habitat and pinpointing
their location so that later visits could be made to upgrade the
evidence to probable or confirmed levels. For Ontario Atlas Maps
presented in WILDSPACETM on the web, probable and confirmed
levels of breeding evidence have been combined.
For more details on Atlas methods, coverages and results, please
refer to the "Atlas of the Breeding Birds
of Ontario" by Cadman et al. 1987.
Some of the highlights reported include several new Ontario breeding
species, some species found more frequently than expected, other
previously recorded as breeders not reported, as well as several
range extensions to the north. The 11 species found in the most
blocks in the entire province were Herring Gull, Mallard, Tree Swallow,
Spotted Sandpiper, Swamp Sparrow, White-throated Sparrow, Yellow
Warbler, Yellow-rumped Warbler, Northern Flicker, Red-eyed Vireo,
and Northern Waterthrush. Obvious differences were exhibited between
northern and southern sectors.
Ontario Atlas Maps in WILDSPACETM
Digital versions of the Atlas of the Breeding Birds of Ontario maps showing
the breeding evidence for 294 species in Ontario are currently available
in WILDSPACETM on the web. Not all species are equally
well represented on the maps. The most fully represented species
tend to be conspicuous, well known to atlassers, common, active
(and usually vocal) in the daytime in June and early July, and found
in readily accessible habitats. Generally, the more of these criteria
a species meets, the greater the likelihood of its being found by
atlassers. For example, owls are probably not well represented because
they are nocturnal, active early in the season, and generally poorly
known. The same can be said for other nocturnally active species.
The digital versions of the maps contained in the "Atlas
of the Breeding Birds of Ontario" were produced
in cooperation with the Landscape Analysis and Applications Section,
Canadian Forest Service and Environment Canada's Geomatics Unit.
This involved the creation of a grid composed of a 10 km2 cells
covering the entire province similar to the referencing system used
on the 1:250k National Topographic Data Base (NTDB) 1:250,000 map
sheets. Once completed, each of the 3727 cells of the grid were
attributed with breeding evidence information for each species that
was surveyed for the project (see Map
of Ontario Showing Survey Cells). Thematic breeding evidence
maps for each species were then generated by superimposing the grid
cells over an outline of the province. A unique colour was chosen
to differentiate the various ratings for evidence of breeding ie.
not surveyed, not observed, possible, and probable or confirmed.
The projection parameters incorporated for these maps are as follows;
Projection: Lambert Conformal Conic
Spheroid: Clarke 1866
Central Meridian: -92 00 00
Reference Latitude: 45 00 00
Standard Parallel 1: 49 00 00
Standard Parallel 2: 77 00 00
False Easting: 00 00 00
False Northing: 00 00 00
References
Cadman, M. D., P. F. J. Eagles, and F. M. Helleiner. 1987. Atlas of the Breeding Birds of Ontario. University of Waterloo Press, Waterloo, Ontario.
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