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Ontario Butterfly Atlas Online: Further Information


(L to R) Alan Macnaughton, Bev Edwards and Ross Layberry,
March 2016. (Colin Jones is below.)


Colin Jones

(link back to the main atlas page)


The Ontario Butterfly Atlas Online is the longest-running effort in North America to organize citizen scientist (amateur naturalist) butterfly distribution data. See the TEA's page on the North American Butterfly Monitoring Network for more information on how this project compares to other butterfly monitoring projects in North America.

The latest version of the atlas, released in March 2016, is based on 280,000 butterfly records: all TEA seasonal summaries (Ontario Lepidoptera), which cover the period 1969-2014; records submitted to e-Butterfly up to January 2016; specimen data from many museums, including partial data from the Royal Ontario Museum; and the private records of more than 75 individual observers. About 98% of the observations are of adults, but observations of other life stages are also included. Butterfly count data is included only to the extent that it appears in individual contributors' reports with specific location information.

On the main atlas page, when you select a particular species and a particular map type, the map will show only the geographical areas where that species has been found. For example, by selecting "143. Mourning Cloak, Nymphalis antiopa" as the species and "counties" as the map type and then clicking the button "Display Results," only those Ontario counties where the Mourning Cloak has been found will be shown on the map.

The atlas can be used to display species lists for particular areas, as well as all of the underlying records (including location, observer, date, etc.) See the discussion of information windows below.

If any maps do not seem to be displaying correctly, click "refresh" on your web browser. This will force the web browser to load the most recent version of the atlas page. The reason for the problem is that to reduce load times, some browsers store web pages on the user's computer, and these can become out of date.

Send comments and corrections to Colin Jones (colin.jones@ontario.ca), Ross Layberry (rosslayberry@yahoo.ca) or Alan Macnaughton (info@ontarioinsects.org).


The Main Atlas Page

The display of the large maps can be customized by the user using drop-down menus and radio buttons. For drop-down menus, click on the downward-pointing arrow on the right-hand side to display the set of choices. Each of the menus is explained below.

Select a Butterfly

This drop-down menu can be used to produce a distribution map for any one of the 168 species of butterflies recorded in Ontario. The species names (scientific and common) are the same as in the TEA seasonal summaries published as Ontario Lepidoptera (yearly reports published since 1969). The initial order is taxonomic--roughly speaking, the order in which the different families and species are believed to have first appeared on the earth. Clicking on the button "alphabetic" will change to alphabetic order based on the common name. For the alphabetic order, species may appear in more than one place (e.g., "Roadside Skipper" and "Common Roadside Skipper." Thanks are due to Ed McCurdy for the programming of the alphabetic list.

For older records, the set of species names which are recognized by taxonomists now is different from the set of species names which were in use when the butterfly observations were made. Accordingly, certain records of azures and tiger swallowtails have been recoded to recognize the new species definitions, e.g., some observations recorded as Eastern Tiger Swallowtails before the late 1990s have been recoded as Canadian Tiger Swallowtials. See this page for more details.


Select a Map Type

Map types available are squares, counties, national and provincial parks, circles (generally 50 km in radius, around major cities and Point Pelee National Park), eButterfly points and predicted range maps.


The most detailed TEA map of the occurrence of each species is by squares of 10 kilometres by 10 kilometres -- 10,747 in all, covering every part of Ontario. These squares were orginally developed for the Ontario Breeding Bird Atlas, and a file of the definitions of these squares has been made available to us by Bird Studies Canada.

As noted above, the TEA has records from only about 20% of these squares, but MNR road maps show that 45% (4,802) of the squares are accessible by public roads. In this pdf, squares with records are marked in red, while squares which have roads but no records are show in gray. White areas (outside of squares) are inaccessible by road. However, some of the roads in the far north may be usable only when the ground is frozen. These "winter roads" would be useless for butterflying. These roads might include the roads around Moosonee on the James Bay coast and the roads north of Pickle Lake in the northwest.

One of the items given in the information window is the code for that particular square. Each code is 6 characters long. Consider the square 17NU41. The The first 2 characters ("17") identify the "zone". The next 2 characters ("NU") identify the "block" (generally a square 100 km on each side) within that zone. The final two characters ("41") indicate the specific 10 km square within that block. The location and naming of the square is explained further in this figure from Bird Studies Canada. The map shows that a few "seam squares" at zone boundaries are of smaller size than 10 km by 10 km and are more like triangles).

The reported locations for some older records are too imprecise for these records to be assigned to particular squares (e.g., "Algonquin Provincial Park"). Such records are excluded from the squares maps but are included in the maps for larger areas such as counties and parks. As a result, the squares maps are constructed using only about 95% of the total records.

If you want to visit a particular square to check out the butterflies there, topographic maps of most squares in pdf form are available from Bird Studies Canada. Also, the view from roadsides in most areas of the province can be seen on the atlas maps using Google's StreetView (the stick figure at the upper left of the map).


We have divided Ontario into 49 units based on political boundaries, which we call "TEA counties." We use the term "counties" because this was the former name for all upper-tier municipalities in southern Ontario. The 49 units include 27 units with "county" or "counties" in the name, 11 districts (e.g., Algoma District), 6 regions (e.g., Waterloo Region), and 5 single-tier municipalities (Chatham-Kent, Hamilton, Kawartha Lakes, Ottawa and Toronto).

We have combined separate political units where it makes sense because a larger unit entirely surrounds one or more smaller units (other than perhaps at the outside edge). This, in 14 counties where one or more municipalities formerly included in the county are now separate, we continue to include the municipality in the county (e.g., Kingston and Frontenac County). Similarly, the City of Greater Sudbury is included in Sudbury District. Finally, First Nations lands are included in the neighbouring or surrounding TEA county, e.g., Six Nations land near Brantford is considered to be part of Brant County.

The complete list of the 49 TEA counties and their definitions is provided in this Excel spreadsheet.


This map shows 711 areas which we call parks.

The main elements are: 342 Ontario provincial parks and 295 conservation reserves; 22 federal protected areas, including Georgian Bay Islands, Pukaskwa, Bruce Peninsula, Long Point and Point Pelee; and 7 non-governmental reserves. The ESRI shape files for these parks were provided to the TEA as a result of its membership in the Ontario Geospatial Data Exchange, and downloaded from the Land Information Ontario Warehouse, Ministry of Natural Resources and Forestry, Government of Ontario. It contains information licensed under the Open Government Licence – Ontario.

Other parks were mapped using shape files provided by the City of Toronto (including High Park), the National Capital Commission (including the Mer Bleue Bog), Ontario Nature (including Stone Road Alvar and Lost Bay), rare Charitable Research Reserve (located in Cambridge), and the United Counties of Prescott-Russell (Larose Forest). Lastly, the species list for the Rouge National Urban Park Study Area (to be finalized) was based on data provided by Parks Canada Agency.


For this map, we draw circles around the centres of Toronto, Hamilton, Ottawa, Kingston, Sudbury, Sault Ste. Marie, Thunder Bay, and Point Pelee National Park. The radius is normally 50 km (e.g., for Toronto, we use the 50 km circle around the Royal Ontario Museum which is employed for the TEA's Toronto butterfly checklist). For Hamilton, we follow the practice of the Hamilton Naturalists' Club and use a 25-mile (approximately 40 km) circle around Dundurn Castle.

Note that although some of the circles show areas in the US and Quebec, the atlas does not include butterfly observations for those areas.

eButterfly Locations (Latitude-Longitude Points)

All data submitted to eButterfly has been provided to the Ontario Butterfly Atlas. Since each observation submitted to eButterfly is displayed on that website showing the precise latitude and longitude of the observation, we do the same here. The other data submitted to the Ontario Butterfly Atlas is not included in the points display because the observers have not given permission to do so.

Predicted Range Maps

The ROM Field Guide to the Butterflies of Ontario includes predicted range maps for 105 species. Due to lack of space, each of these maps took up a space of less than 4 cm by 4 cm on the page. By arrangement with Maxim Larrivée and Michelle Staples, these range maps are presented here as full-screen images.


Select a Part of Ontario to View

When you click "Display Large Map", the screen will, by default, show a map of central Ontario. To have the large map open to a different view of Ontario instead, choose any one of the 18 items on this drop-down menu. The choices are major cities (Toronto, Ottawa, Hamilton, etc.), regions of Ontario (south, south-west, east, etc.), or the entire province at once.


Select Colours for Display of Map Areas

The atlas offers two different ways in which map areas can be coloured on the map: by year of most recent record, and by year of first record. Clicking on the relevant button makes this choice. Colouring by year of most recent record is useful in order to determine which species have not been seen in an area for a long time. Colouring by year of first record is used to draw attention to the most recent observations.

Most Recent Record

For this choice, areas with the newest records are shown on the map in green; areas which have somewhat older records are shown in yellow; and areas with the oldest records are shown in red. The areas can be squares, counties, parks, circles and points, depending on the map type chosen.

The dividing lines between green and yellow and between yellow and red are initially set such that on the large map, areas are shown in green if there is at least one observation for 2011 and subsequent years, areas are shown in yellow if the most recent observation is between 1994 and 2011, and areas are shown in red if the only observations are for 1994 or before. However, this drop-down menu allows these dividing lines to be chosen by the user. For example, the dividing line between green and yellow observations could be set to be 2014; this would show areas with 2014 observations in green.

For maps of squares, some errors in showing the colour of squares may occur when a lot of squares are to be shown on the screen at once, e.g., a map showing "any species" for the entire province on the screen. In particular, squares may be shown as green when they should be yellow or red. This is due to the limitations of the free version of Google's mapping software.This problem can be overcome by zooming in to show less squares on the screen, and then clicking on the square in question. This problem does not areas with maps of of other types of areas (parks, counties, etc.) as it is only with squares that the number of areas shown on a particular map becomes large enough to cause problems.

First Record

Under this choice, the green, yellow and red colours are used to used to indicate the year in which the first record for the area occurs. The default choice is to use green for map areas in which the first record is for 2014; yellow for map areas in which the first record is for 2012 or 2013; and red for map areas in which the first record is for 2011 or before. Thus, if the map type is "county", counties shown in green will be new county records for that species.

The meaning of the three colours can be changed using the drop-down menus. For example, to show all squares for which the first record for that species is 2013, the drop-down menu besides the green colour would be chosen to be "2014 or later", and the drop-down menu beside the red colour would be chosen to be "2012 or before."

Selecting this choice will map only observations in which the year of the observation is known. Thus, the few thousand old museum records in which the year of observation has not been recorded are excluded if this choice is selected.

Select which Records to Map

Clicking on the relevent radion button allows the production of maps based on all records vs. 2014 records only.


The Large Map

On the large map, the left-hand bottom corner is occupied by a legend containing 4 items:
- the common name
- a picture of the adult, where available. (Click on the picture to see an enlarged version.)
- the number of squares where that species has been found (for squares maps only)
- a display of boxes showing the 3 colours used on the map and what each means

The size of the legend is the same for all user screen displays and may occupy too much of the screen for users with smart phones and tablets. Therefore, the legend is not displayed if the program detects that the user is accessing the atlas through a smart phone or tablet.

All pictures are of Ontario specimens, except for a few species rarely seen in Ontario, such as the Orange-barred Sulphur, the Zarucco Duskywing and the Mexican Yellow. The pictures were supplied by Rick Cavasin, Colin Jones, Norbert Kondla, Maxim Larrivée, Glenn Richardson, Bryan Reynolds (of the Butterflies of the World Foundation, www.botwf.org) and Bob Yukich.

Zooming and Panning

To zoom in or out on the large map, use the slider bar (top left of screen) or your mouse wheel. To see areas outside the screen (pan the map), click the directional arrows on the white circle (top left of screen) or click and drag with your mouse.

The amount of zooming and panning required can be reduced by using the drop-down menu "choose a part of Ontario to view" on the main atlas page. For example, the user can choose "Ottawa" to go directly to the couple of dozen squares in the Ottawa area when "Display Large Map" is clicked. Another benefit of this menu is that when the user clicks on an area to display records (see below) and then uses the browser's "back" button to return to the map, the view of Ontario displayed will be one chosen through the drop-down menu. Otherwise, some browsers will return the user to the initial zoomed-out view.

A scale on the bottom left of the map shows distances in both kilometres and miles.

Map Opacity

When the user is zoomed out so that most of the province is visible on the screen at once, map areas are opaque. This provides rich, strong colours which make the map areas in which the species is found highly visible. When the user zooms in so that the screen covers an area of perhaps 600 km by 600 km, the map areas automatically become more transparent, so the user can see the geographic features (roads, cities, etc.) underneath the map areas. Map areas become even more transparent when the user zooms in so that the sceen shows an area of perhaps 30 km by 30 km or less. Thus, the map automatically adjusts between 3 levels of opacity as the user zooms in or zooms out.


Information Windows

Much of the information stored in the atlas is available through clicking on particular areas (the individual square, county, park, circle or point) to show the information window--a pop-up box displaying data and containing links to further information. The contents of this box differs when it is accessed from an "all species" map as opposed to a map for a particular species.

Displaying the Species List

The information window for the "all species" map shows a species list. The number of observations recorded for each species is also shown. At the bottom of the window, there is a list of the top 10 contributors of data for that area, as measured by the number of observations submitted. Contributors are shown in codes based on their initials -- the same codes used in TEA seasonal summaries.

Users of the Firefox browser will sometimes find that text spills outside the info window, in which case it becomes hard to read. Viewing the page in Internet Explorer or Chrome seems to solve this problem.


Displaying the Underlying Data for a Particular Species

The information window for maps of particular species (Silver-spotted Skipper, etc.) displays 4 tables of links to further information.

The first table provides links for the display of records for that species--adults vs. caterpillars and ova, and the particular area vs. the whole province. All 246,000 records in the database can be accessed in this way. The second table provides similar links, but for all species rather than just one particular species. The third table provides links for species and contributor lists.

All observations of one species by one observer (or group) in one day in one location are combined into a single record. Specimens are treated similarly; all such specimens are combined into one record, even if the specimens are held by different museums.

The information displayed for each record is a total of 19 data fields, including the date, observer, location, number of adults and number of immature stages seen, and any field notes submitted. Much of this information is also available from the TEA seasonal summaries, but this is a more convenient method of access. Also, every observation which has been submitted can be accessed; the seasonal summaries report only selected observations.

One of the 19 data fields is "location." This is a verbal description, generally the same one that appears in the TEA seasonal summary or eButterfly record. No latitude and longitude values are disclosed, although these are known and are used in the mapping process to assign observations to areas (squares, etc.).

The reason for not disclosing the latitude and longitude values is that much of our data was submitted without permission being given for the exact locations to be made public. Observers might not want this information given out because (1) the species is rare or endangered, or (2) the observation was made on private lands (and perhaps only the original observer had permission to visit them, or access was given on condition that no attention be drawn to that land).

Displaying the Seasonal Abundance Data for a Particular Species

When the "select a map type" drop-down menu is set to "10K squares" or "10 km squares without county boundaries" and "select a butterfly" is sset to a particular species, clicking on a particular square brings up an info window which includes a section labelled "seasonal abundance charts." To see these charts, click on the first entry under this heading, which is labelled "complete data for this square." In addition to charts showing the data on this species by month-thirds (36 for the year), other data shown includes the earliest and latest records in the year for this species in this square, as well as similar earliest and latest records for the county, for the county together with its adjoining counties, and for the forest region (of which there are four in the province).

The final main link in the information window is for all records of immatures (ova, larvae or pupae) of that species province-wide. This is about 2,000 of the 195,000 total records. Displaying these records often yields useful information on foodplants and ovipositing behaviour. Where an immature life stage has been removed from the wild for rearing, the date shown on the record is the date it was removed from the wild.


Special Maps

[to be supplemented with further description]

The selection "no species" is to be used to show geographical areas where no butterfly records are presently available. Users are encouraged to visit those squares to eliminate them from the list for the next version of the maps.

The frequency of "no species" areas varies with the map type; map types showing larger areas are much less likely to have areas in this category. For example, we have records for all Ontario counties, but only 20% of the 10 km squares. The 80% of the squares which are currently in the "no species" category are mostly in sparsely-populated northern areas.

The "no species" map for squares has some distinct features. County boundaries are shown in green, and only squares south of 49.6 degrees latitude are shown. The latter mapping restriction is forced by computer issues; the number of distinct areas that can be drawn on a single map is limited to about 5,000. Thus, the most northerly 3,000 of the 8,000 empty squares in Ontario are not shown on the map.

Computer Issues

If you get the message "Data may still be loading -- drag or refresh the page to find out", do not wait for the page to load, as the screen display is not automatically updated when the page is ready. Instead, zoom in and zoom out as necessary until you see the finished map.

Some older browsers may not work with the atlas. The squares do not show up on the maps for Firefox version 3.6.13 and Netscape Navigator 9.0. Neither the squares nor the maps appear for Safari 1.0.3 and Internet Explorer 5.2). On the other hand, Internet Explorer 6.0 (released in 2001) has no problems.


Help the Atlas Project!

Please check over the maps. Let us know if any records seem out of range, as errors in entering latitude and longitude values can occur.

As noted above, problems in working with the online maps can occur with some combinations of computers and web browsers. So, please try this database and mapping capability, and report any problems you are having.

More data, both old and new, is needed to make these maps better. Please let Colin Jones, Ross Layberry or Alan Macnaughton know if you have access to such data. See what species have been recorded in the 10K squares in your area -- many squares have no records, or just a very few species. See this page for instructions on gathering data. Both members and non-members are welcome to contribute.

Thanks are due to Andrew Couturier of Bird Studies Canada for providing the data file dividing Ontario into the 10,747 squares. Also, Glenn Richardson (TEA president) wrote the HTML code and designed the main atlas page and the legend on the large map.

Future Plans

A printed version of this atlas will be made available when a reasonably complete set of records has been gathered and the records have been carefully examined to identify errors.

This atlas is only maps and the associated data. In that respect it is different from the TEA's 1991 Ontario Butterfly Atlas, by A.M. Holmes, R.R. Tasker, Q.F.Hess, and A.J.Hanks, which also included life history information. This information, as well as photos of both adults and caterpillars, are to be included in the Royal Ontario Museum's planned field guide to the butterflies of Ontario. For now, readers may consult the free publication The Butterflies of Toronto, which was published in September 2011 in the Toronto Biodiversity Series.


Information for Atlas Developers

The programs underlying this online atlas are freely available to others who might wish to use them for their own atlas projects, whether for butterflies or for other insects, reptiles, etc. Contact Alan Macnaughton. The Maritimes Butterfly Atlas has produced their own maps using these programs. This February 2012 paper in the Lepidopterists' Society News describes the making of the atlas, although it was written before the atlas used a Fusion Tables API (written in Javascript).

The data points in this Atlas were assigned to particular areas (squares, parks, etc.) using version 1.7 of QGIS, a freely-downloadable GIS (geographic information system) program, although ArcGIS or other programs could have been used. The web maps were drawn using Google Fusion Tables. The preparation of the files for both QGIS and Google Fusion Tables was done in Microsoft Excel.


Other Atlas Projects

This TEA page provides a description of other butterfly atlas projects in BC, the Maritimes, various states in the US, and the UK.