surveys of the status of northeastern Chorus Frogs
Pseudacris triseriata

This page presents brief summaries of surveys of regional or local populations of northeastern Chorus Frogs since the 2001 First Annual International Conference on Northeastern Pseudacris triseriata in Kemptville, Ontario.

The purpose of this page is to assemble information for testing the assertion of the Chorus Frog Declaration that "none of us know of a region in the lower Great Lakes or St Lawrence basin where Chorus Frog populations can safely be regarded as stable." There's some overlap with items on the the Chorus Frog news page, from the first draft of which this was extracted. -- fred schueler -- 22 February 2006.


2006 -- Southern Ontario Chorus Frog survey
prevalent along the Thousand Islands Parkway, Ontario
not heard, 1978-2005, in Osgoode Township, south of Ottawa
Abundant around Ontario Power Generation plants
not found within 20 km of downtown Toronto
Stable in Niagara
Stable in Pererbourgh County for the past decade
Extinction on the Five-Mile Block, Tobermory, Ontario.
patterns of decline in SW Ontario
No Chorus Frog decline in Lanark and Frontenac, Ontario
No decline in Wolford Township, eastern Ontario
No decline around Detriot, Michigan (2005)
Survey around James Bay, Ontario and Quebec:
No decline around Detriot and Ann Arbor, Michigan (2001)
Survey along Highway 7 and South of Lake Simcoe, Ontario (2001)
SURVEYS of EASTERN ONTARIO (2001): Glen Robertson and N of Morrisburg
SURVEYS of EASTERN ONTARIO (2001):Seburns' resurvey of Wayne Wellers 1990 sites. Long Sault- Alexandria
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2006 -- Southern Ontario Chorus Frog survey -- Frederick W. Schueler (this is a truncation of our report to our funders, with literature citations deleted, or replaced by links to accounts in this website).

The "Western" or Midland Chorus Frog is a tiny frog: snout-vent length only about 25mm, and weighting 1 gram as an adult. It is found in Canada in the lowlands of southern Ontario and southwestern Québec.... Once considered a subspecies of Pseudacris nigrita, through the second half of the 20th century P. triseriata was considered one subspecies among four: P. t. triseriata (Western or Midland Chorus Frog), P. t. maculata (Boreal Chorus Frog), P. t. ferarium (Upland Chorus Frog) and P. t. kalmi (New Jersey Chorus Frog). These subspescies were considered species on the basis of differences in advertisement calls and morphological measurments by Platz and Forester in 1988. Since then, triseriata has been widely considered a monotypic species, Pseudacris triseriata, but this taxonomy has been subject to controversy..

Moriarty and Cannatella presented genetic evidence that the widespread morphologically delimited taxa of Chorus Frogs within the triseriata - maculata - ferarium - kalmi clade were polyphyletic, so the taxonomic position of this group is now problematic. From Canada, they had only one sample of 'triseriata' (from eastern Ontario) and that clustered with northern Ontario 'maculata' rather than with a Michigan 'triseriata' sample, which clustered with kalmi and feriarum.

On the face of it, this suggests that St Lawrence-Lake Ontario Chorus Frogs re-evolved the triseriata morphology (which may be only longer legs adapted for warmer temperatures, and the lack of green and red colour forms) from Boreal ancestors that spread through the northern grasslands now represented along the shores of James Bay. The present range of P maculata along James Bay may only be the kilometre or few hundred metres that has most recently emerged from the Bay through isostatic rebound, over the past century or so. The ancestors of St Lawrence-Lake Ontario Chorus Frogs may well have reached the shores of the Champlain Sea and proto-Great Lakes long before the present range of the species in northern Ontario and Quebec was free of ice...

In the preparation of a revised status report for the species, prompted by recent evidence of declines in Quebec, it became evident that there was a need to make a concerted effort to work out the species' status in Ontario. Memory suggests that Chorus Frogs have declined in Ontario, since the 1970's, from 'ubiqutous' to 'scattered', but there aren't data (or sequestered data haven't been assembled) to document this directly. Seburn & Seburn documented a decline in Ontario Herpetofaunal summary (OHS) records, controlled by records of the closely related Spring Peeper (P. crucifer) between Lake Erie and Lake Huron, however, and there are signs of a widespread disappearance in eastern Ontario . This hypothetical (and possibly nostalgic) general decline, combined with the question of the possibly different conservation status of the triseriata and maculata lineages, led to this spring's field work across much of southern Ontario. The major trip was hastily planned after the beginning of calling in eastern Ontario, depending on real-time GPS navigation to cover the greatest area most efficiently.

Methods: Our strategy was to revisit sites where Chorus Frogs had been recorded in the Ontario Herpetofaunal Summarry (OHS), and to collect specimens for genetic and morphohologal analysis, to test the hypothesis that there's regional differences in the rate and nature of any decline, that might be associated with a future delineation of the ranges of the triseriata and maculata lineages. We planned to visit a series of areas, each to be sampled on a single night, listening at sites following the auditory monitoring protocol we used on the Lake Ontario waterfront and in eastern Ontario.

In the first week of calling, before funding, hardware, and software were assembled, we surveyed our local auditory monitoring sites north and south of Bishops Mills, the western South Nation drainage basin, and the Thousand Islands Parkway. Jennifer Schueler and I set out for southwestern Ontario, on 16 April, after Chorus Frogs had been calling for 10 days in eastern Ontario. We were uncertain of the best sampling strategy, given the fact that were starting late in the season, had planned such a short period (1 night) in each area, and would have to deal with the different circumstances of nocturnal and diurnal listening. We planned to listen for diurnal calling as we moved between areas, and to focus on a series of regions during the nights... What we wound up doing was to navigate towards previous OHS records displayed on a laptop GPS program, seeking to hear Chorus Frogs or a good chorus of other species in each cluster of previous Chorus Frog records. Probably due to dry (and sometimes very windy) conditions and the lateness of the season, we encountered almost no diurnal calling, which restricted our surveying to the nights, and left us puzzled about the status of the species in areas where little nocturnal calling was heard, especially when night-time temperatures were in the low single digits. We were also constained by nights when members of the expedition weren't well enough for an all-night survey.

Our criteria for roadside choruses was those that could be heard through the open windows of the van as we cruised at 60 km/hr, while the navigator watched waypoints scroll up on the laptop GPS programme until they were about 50-100 metres away, when he called for a halt, and we got out and listened for calling Often the driver could see the laptop screen clearly enough to do the final approach herself.

Results: Through March, April, and May we made 950 records of calling Anurans, Birds heard within the auditory monitoring protocol, and registering "no observation" where we expected to hear calling. This was pruned to 865 by deleting entomological records and avian records where anuran calling would have been improbable. The first and last Chorus Frogs were heard on 5 April at Hare Hill Rd/Bolton Rd, and 9 May at Co Rd 20, 0.8 km NE Oxford Station, both in North Grenville Township, Grenville County. Deleting records before and after these 34 days left 710 records, 21 records/day, or 8.1 unique sites visited per day throughout the month of listening. (click "view image" to see details)
[2006 Chorus Frog fieldwork]
We heard Chorus Frogs at 99 of 272 sites, and as 113 of the 710 records, where we listened. Seventy-four of the records were, however, at our home in Bishops Mills where we haven't heard Chorus Frogs since 1992. Anurans were heard at 244 (90%) of the other sites, and Chorus Frogs at 36% of the total, and 41% of the sites where anurans were heard. There was an average of 2.4 records, and 2.1 species (counting "no observation" as one species), from the sites away from home.

Our success in surveying the ares we'd targetted in our proposal to Environment Canada was as follows:

-) Brockville-Rideau auditory transects (done)
-) western South Nation River drainage (done)
1) Thousand Islands Parkway (done)
2) Lake Ontario Waterfront listening sites (Trenton-Toronto, attempted three times, but weather unsuitable)
3) Toronto area (skipped)
4) Long Point area (skipped, auditions here by Tana McDaniel)
5) Essex County (done)
6) mainland Grey/Bruce (replaced by two diagonal transects through interior southwest Ontario)
7) Tobermory (done with John Francis)
8a) Parry Sound area (not done)
8b) Renfrew County (done by Wayne Weller)
9a) Collingwood area (done fairly well plus auditions by Anita Miles, Collingwood Museum)
9b) Hwy 7 between Peterborough and Ottawa (attempted, but weather unsuitable)
10) Dywer Hill Road (done)

By counties the records came from (number of records, followed by number and percentage of Chorus Frog records):

Grenville County 280, 25 9% Chorus Frogs
Leeds County 121, 33 27%
Essex County 61, 22 36%
Ottawa-Carleton Region 36, 7 19%
Northumberland County 30, 3 10%
Oxford County 27 0 0%
Prince Edward County 26, 0 0%
Perth County 23, 3 13%
Bruce County 22, 0 0%
Elgin County 18, 4 22%
Middlesex County 13, 4 31%
Grey County 11, 3 27%
Huron County 9, 1 11%
Kent County 8, 1 13%
Lanark County 5, 3 60%
Durham Region 5, 0 0%
Lambton County 4, 1 25%
Halton County 2, 0 0%
Wellington County 2, 0 0%
Hastings, Lennox & Addington, Peterborough, Stormont-Dundas&Glengarry, Simcoe counties and York Region.. 1, 0 0% each

By species we heard (percentages are of records, not of sites):

Pseudacris crucifer (Spring Peeper) 217 31% + 1 doubtful
Bufo americanus (American Toad) 140 20%
Pseudacris triseriata (Striped Chorus Frog) 110 15% + 3 doubtful
Rana pipiens (Leopard Frog) 71 10%
Rana sylvatica (Wood Frog) 53 7%
Scolopax minor (Woodcock) 18 3%
no observation 15 2%
Gallinago gallinago (Snipe) 13 2%
Branta canadensis (Canada Goose) 11 2%
Hyla versicolor (Tetraploid Gray Treefrog) 11 2%
visit 7 1%
Agelaius phoeniceus (Redwinged Blackbird) 5 1%
Charadrius vociferus (Killdeer) 5 1%
Turdus migratorius (Robin) 5 1%
Canis latrans (Coyote) 4 1%
Melospiza georgiana (Swamp Sparrow), Strix varia (Barred Owl), Zonotrichia albicollis (Whitethroat Sparrow): 3 each
Rallus limicola (Virginia Rail) & weather (climate observation): 2 each
Caprimulgus vociferus (Whippoorwill), Castor canadensis (Beaver), Gavia immer (Common Loon), Melospiza melodia (Song Sparrow), Podilymbus podiceps (Pied-bill Grebe), Porzana carolina (Sora), Rana clamitans (Green Frog), and Tachycineta bicolor (Tree Swallow): 1 each.

I won't attempt an analysis here, except to say that the Seburns' (2001) conclusion that there have been declines in central-southwestern and Huron shore areas seems to broadly fit the data, and that there are areas in eastern Ontario where there haven't been declines since the early 1990's.. Future analysis of calling data gathered in 2006 by ourselves, Wayne Weller, Mike Oldham, Anita Miles, Dave Seburn, Tana McDaniel, Brian Hickey, should allow conclusions about the species' status throughout southern Ontario.

Acknowlegements: Thanks to Jennifer Schueler for her exemplary filial assitance in the field, and to Aleta Karstad for getting us launched and sampling around home while we were gone. Judy Courteau, Paul Pratt, Anita Miles, John Francis & Wanda Thompson, and Rory Tanner provided help while we were in the field. Thanks to Environment Canada and Lars Karstad & Canadian River Management for providing funding.

Subject: [NatureList] Chorus Frogs prevalent along the Thousand Islands Parkway
Date: Sat, 15 Apr 2006 12:06:11 -0400
From: "Frederick W. Schueler" <>
Organization: Bishops Mills Natural History Centre
To: Eastern Ontario Natural History list-serve <>,
ottawa herps <>


Jennie and I were to have set out yesterday on an heroic swing through all of southern Ontario, in pursuit of replication of Chorus Frog records from the Ontario Herpetofaunal Summary (OHS) database, and collecting specimens for genetic and morphohologal analysis, to test the hypothesis that there's a correlation between the rate of decline, and the recently disclosed genetic differences between the eastern and western forms in Ontario. But glitches in installing Foxpro on the wonderful new laptop which is supposed to solve our navigational and data-recording problems kept Aleta occupied all day (the patch didn't, in a word), and Jennie was suffering from the tail of a cold, so yesterday evening Aleta and I set out on the first leg of this proposed survey: revisitng our and OHS Chorus Frog sites along the Thousand Islands Parkway, from SW of Brockville to NE of Gananoque, and then returning home along Hwy 2, Co Rd 5, the Temperance Lake/New Dublin Road, and North Augusta, Branch, Kyle, Bolton and Buker rds, to home.

We cruised down the Parkway at 60 clicks, and I'd watch a waypoint scroll up on the GPS until it was about 50-100 metres away, and then we'd hear Chorus Frogs. It was as simple as that (at least for me -- Aleta had to exercise all her considerable skill in not-backing-into-mailboxes when we'd overshot a site by 100 metres). We heard Chorus Frogs at almost all the previous sites, and filled a 10km gap between clusters of records that had been present in both my records and those from the OHS.

So Chorus Frogs are clearly not in decline along the Parkway. They've got everything going for them there: the long aboriginal strip of riverside marshes and swamps (largely protected by the National Park), water held in the irregular bedrock of the Frontenac Axis, the ditches and little ponds of the half-finished, old-stle Parkway, and cottagy residences where people evidently don't fell the need to destroy every patch of wetland.

On the way back we drove faster (75 km/h), and stopped at the seven places where Chorus Frog calls came in the window, all SW of New Dublin. There was a light drizzle on the way back, but very few Anurans on the road either before or after the rain began. Only on the Branch Road, after 02h00, did we see a scattering of frogs (cf Rana pipiens) active on the roads. -- fred.

No Chorus Frogs over 27 years in Osgoode Township, south of Ottawa: are pesticides responsible?

At 6123 Snake Island Road, R. R. # 1, Osgoode, Ontario, UTM 18T 0453821, 5003433 (WGS84), an area of about 600 m x 600 m, in permanent residence at the site from 1978 to 2005, Bev Wigney has never heard Chorus Frogs, though the habitat seems ideal: oldfields and stands of successional aspen and birch forest, with two large drainage ditches approxmately 4 meters wide x 400 meters long and several nearby isolated ponds. The predominant human impact is pine forest plantations to the east with some spraying of trees in those forests, and extensive spraying of nursery sod farms approximately 150 meters from one of the drainage ditches. The nearest OHS record is an audition 4 km NNW, 29 April 1989, by Stephen Darbyshire.

Other frogs at this location include strong chorus of Spring Peepers in most years; Wood Frogs breeding in the drainage ditches; Gray Treefrogs frequently seen and heard Leopard Frogs frequently found in the fields and particularly around a small garden pond; American Toads also frequently found in the gardens.

"If Chorus frogs are more sensitive to herbicides, etc.. than other species, that might account for their absence around our farm. This land was used for potato farming before we bought it. When we came here, the soil was sort of sandy and dead looking with just some very poor meadow grasses as the farmer had stopped farming and everything was becoming meadow. However, I expect he did some spraying. The major drainage ditch that runs through our property once connected to a ditch along a farm field where the farmer did a lot of spraying. The ditch has now been blocked off at that upstream end. In recent years, it has become something of a haven to frogs and other creatures. However, at the downstream end (further down from my farm), it passes through the Christmas tree farm that sprays, and joins into another larger drainage ditch which would get a lot of run-off from the nearest sod farms -- and they use a lot of herbicides.

" I have a feeling that our piece of land is becoming increasingly impervious to pesticides as the vegetation thickens and the ditches become clogged with wetland plants. That may well explain the increasing numbers of creatures of all kinds that are appearing here now -- I would have to say that is almost for certain in the case of the insect life as I'm finding a lot of species now - more than can probably be accounted for by my degree of observation. However, the pesticide spraying is still a factor here. It can be very noticeable in summer depending on the stage that the sod is at in its production cycle. Almost every bit of workable land surrounding us for more than a km. is now in sod -- we have 3 different companies operating fields in 3 directions now. In other words, there's a whole lotta sprayin' goin' on."
Bev Wigney, 11 March 2006
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Abundant around Ontario Power Generation plants

In 2004-05 my surveys suggest that chorus frogs are quite abundant. I found them quite numerous while doing marsh monitoring at Ontario Power Generation's Lennox Generating Station site, Nanticoke GS , and Lambton GS, and throughout vast areas of the countryside around our stations. Chorus frogs were common and widespread on these properties in 2005, and quite common throughout the countryside in 2003 and 2004.

Lambton GS - 40J/16 17TLT 805 391 - N42.79713 W82.46112 (St Clair River, S of Sarnia)
Nanticoke GS - 40I/16 17TNT 774 393 - N42.80434 W80.05322 (Lake Erie, E of Port Dover)
Lennox GS - 31C/2 18TUD 526 904 - N44.15393 W76.84288 (Lake Ontario, SW of Kingston)

Wayne Weller, Ontario Power Generation Inc., 8 Mar 2006
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Natural Heritage Planning for Amphibians and their Habitats, Natalie Helferty calls the Western Chorus Frog one of the "species that have been extirpated or are in severe decline in Toronto... all significantly negatively associated with either residential or industrial land use, or both."

Bob Johnson, of the Toronto Zoo, writes " My records indicate that there were about 8 locations in the Toronto area from 1991-94....most were in the Rouge Valley or tablelands (along Reesor Road, S. of Steeles) area but records exist for Toronto Islands, Townline Swamp (Pickering border with Toronto); Don Valley at Science Centre and just south of Science Centre; and East Point park adjacent to Lake Ontario in Scarborough.. These same areas had frogs in 1982, but by 1992 frogs were no longer found in Don Valley at/just south of 401; Don Valley at Lawrence Ave west; and a site south of 401 in Etobicoke. 1982 locations were published by Toronto Field Naturalists in 1983 "Amphibians and Reptiles in Metropolitan Toronto: 1982 inventory and guide" pp. 54 by Bob Johnson.

"Spring peepers blipped out around 1980-83 from the last one or two sites...While Chorus frogs have not been heard from historic sites the grey treefrog continues to persist in the same locations during this period (except for a site near the Ontario Science Centre, but still found just north of there)..."

Paul Prior, Field Biologist of the Toronto & Region Conservation, provides this overview of chorus frog reports on the TRCA Terrestrial Natural Heritage database:

"There are 109 points mapped for chorus frog within the TRCA jurisdiction, 70 of these points having been mapped since 2000, the year that marked the initiation of the current intensive and formalized TNH inventory whereby the intention is to visit every patch of natural cover within the jurisdiction. As of the end of 2005 we’re about 60% done but the coverage is uneven. It should be noted that some of these 109 points refer to discrete ponds and wetlands within a single site.

"So far, the nearest chorus frog points that we have to downtown Toronto are: 1999: report from the Box Grove Tributary of the Rouge, to the south of the junction between 14th and 9th (south Markham). No call code recorded for this report - 24.5 km from [the central downtown intersection of] Yonge and Bloor; 2001: Wildwood Park on the east side of the Mimico watershed - a "call code" [Wisconsin calling index] of 3, so seemingly fairly healthy - 19 km from Yonge and Bloor ; 2002: a total of 9 points mapped for Claireville Conservation Area (west side of Humber watershed), several of them listed as a "call code" 3 - 22.5 km from Yonge and Bloor; 2004: a single point from the NE corner of Kortright Conservation Area (Major Mackenzie amd Islington) - 25.5 km from Yonge and Bloor.

"Sadly, despite fauna and flora (ELC) surveys being conducted recently (2002 +) in many of the larger areas of remaining natural cover in the lower Don watershed - including the Ontario Science Centre wetland - there have been no other reports closer to downtown than the ones listed above.

"As for the remainder of the jurisdiction, many of the points are concentrated along a portion of the South Slope physiographic region, east from Hwy 50 to Hwy 400, and south of King as far as Teston Road (the NE Humber watershed, Vaughan and King municipalities). In this area, there is a particularly high concentration of points in the Nashville Tract, and then again to the south east and to the north of Nobleton. Away from this primary area most other points are from the Oak Ridges Moraine (in the vicinity of King and in the north end of the Duffins watershed - Uxbridge)."

"Much of our amphibian work over the past few years has concentrated on wood frog and, to a lesser extent, spring peeper, with night time audio surveys being conducted throughout April. Since the timing of these surveys coincides with a large part of the chorus frog calling period the surveys allow us the opportunity to effectively monitor chorus frogs, although we have not targeted this species in the same way." (return to Contents)

Stable in Niagara

As for the period of 2004-05 when I returned to southern Ontario, my surveys suggest that chorus frogs are quite abundant... all through the Niagara peninsula, they're widespread and common. Wayne Weller, 7 Mar 2006
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Stable in Pererbourgh County for the past decade

Much of my spring amphibian surveying has been in different areas, trying to record species in as many atlas squares as possible, therefore I do not have much data from the same site over a period of several years. During the past decade when I've resided in the Peterborough area, Chorus Frogs can be commonly heard and are widespread in the agricultural southern portions of the county, though are much more localized northward on the Precambrian Shield where forest cover is more extensive. -- Michael Oldham, OMNR, 7 Mar 2006
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Extinction of Pseudacris triseriata on the Five-Mile Block (Tobermory, Bruce County, Ontario).

Despite George Toner's 1964 assertion that Pseudacris triseriata, the Striped Chorus Frog, was the most abundant amphibian on the Bruce Peninsula, and a scattering of records from the 1970's, on on the outer portion of the peninsula in the 1980's and 1990's this species was confined to a small area southeast of Tobermory, the 'Five-Mile Block.' My surveys in 1984, 1990, and 1992 found the species throughout the block, but in 1997 I heard only 3 choruses, and in a detailed survey in 1999 John Francis heard only a few doubtful calls. In 2001 a survey of all the sites where the species had been heard did not find any, and none have been heard since. Intensified agriculture is the only proposed cause of Chours Frog decline in southern Ontario and the St Lawrence Valley not present here, so it isn’t possible to distinguish among lowering of water levels by gravel extraction, direct loss and fragmentation of habitat, secondary succession of fields to forest with displacement by Wood Frogs, and successive dry years, as the critical cause of the extinction. (this is the abstract of a ms which hasn't been submitted for publication because of hearsay reports of Chorus Frogs on the 5 Mile Block in 2005) -- fred schueler
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No Chorus Frog decline in Essex County, few or none found in Grey, Bruce, Lambton, and Huron counties, Ontario. We conducted repeated surveys at 77, 87, and 91 ponds in the Essex Plain physiographic region in 1992, 1993, and 1994 (primarily Essex County) and found P. triseriata at 12, 14, and 15 ponds respectively. This corresponds to incidence values of 15.5, 16.1, and 16.5 percent of ponds over the three years. Thus, not much evidence of any trends for these three years. I consider these estimates of incidence to be an underestimate however because we surveyed primarily semi-permanent to permanent ponds only, not ephemeral sites.

We did not find any Chorus Frogs during our surveys in the Grey-Bruce and Bruce Peninsula ponds from 1992 to 1994. We have been conducting
similar surveys in the Stratford Plain (Lambton, Huron Counties) at 34 ponds each year from 1992 to 2005 and have detected P. triseriata at only 2 ponds.

My impression regarding patterns of incidence in extreme southwestern Ontario is that chorus frogs are common in the western half of Essex County particularly in the Ojibway Prairie Complex, West Windsor, LaSalle, and along utility rights of way. They also persist in some isolated suburban sites in and surrounding Windsor. They rapidly become less common as you move east or north in southwestern Ontario. I believe chorus frogs are still common near Windsor but I have not searched for them specifically in recent years. -- Stephen J. Hecnar, Department of Biology, Lakehead University -- 6 March 2006.

I can confidently state that from the early-1980s to mid-1990's Chorus Frog was one of the most commonly heard early spring calling amphibians in southwestern Ontario, even in areas where other widespread amphibians (e.g. Wood Frog, Treefrog) were largely absent (e.g. extensively deforested regions of Essex, Kent, Lambton counties). It would be very interesting to resurvey these areas now. -- Michael Oldham, OMNR, 7 Mar 2006 (return to Contents)

No Chorus Frog decline in western Lanark and adjacent Frontenac counties: We live at the western edge of the range of this species in eastern Ontario (Lanark County: Bathurst: Mississippi R, 2.7 km WNW Fallbrook. 44.96661N 76.41983W). We have two vernal pools on our acreage and each Spring there are a few in the pool by the house to a dozen or more in a large 2 acre vernal pool at the eastern side of our property where the water lasts till mid-June depending on the year.

I think that the Chorus Frog populations in this area have been stable ever since we moved here in 1981. There is a great abundance of calcareous waters, swamps, marshes, small lakes, meandering streams, etc. scattered in these old "foothills of the Champlain Sea" roughly between Pakenham in the north to say Sharbot Lake or Bob's Lake in the south. While some of these wet areas receive runoff from farms or people's septic systems, most are pretty isolated. It seems to me that unless some pesticides, fertilizers, metal toxics, etc. fall out of the sky, or UV caused by thinning of the ozone layer actually kills the tadpoles or adults, the populations around here will be secure for the foreseeable future. -- Ted Mosquin, 7 March 2006.

...the area described in my
notes is from Bedford up to Bob's Lake, then around Bradshaw Road, Anderson Road, and on up to Crow Lake, and then along Crow Lake Road over to Hwy 38 (the Road that runs north south from Sharbot Lake down to Tichborne). That area probably has about the most reliable and strongest calling of Chorus Frogs of anywhere we've been in eastern Ontario. Unfortunately, I don't have anything "historic" in the way of records, but we've been driving through that area in spring occasionally over the past 3 years, and the Chorus Frogs are always pretty conspicuous along most of the roads -- there are a lot of soggy areas all through there. I would say that, if you were mapping a boundary, it would lie east of Hwy 38 and south of Hwy 7, going east about to Maberly and Bolingbroke and then down to Fermoy and Bedford. If you haven't been into that area in spring, it is very alive with frog calling -- the kind that you can hear from a moving vehicle. Bev Wigney, 7 March 2006. (return to Contents)

No Chorus Frog decline in Wolford Township: My Chorus Frog observations are based on:11 years of Backyard Frog Monitoring (1.3kmNE WolfordCentre, Grenville Co., Ontario. 44.83152N 75.80269W), 3 years of Amphibian Road Call Counts, and the establishment of a 7-station baseline of Chorus Frog locations in Wolford Township in 2002 (20 records of Chorus frogs from 16 locations). Over that time I have seen no decrease in Chorus Frogs, nor loss of any known Chorus Frog habitats in Wolford Township. -- Stew Hamill, 24 Feb 2006. (return to Contents)

No Chorus Frog decline evident around Detriot, Michigan. Anonymous. 2006. 2005 Rouge River Watershed Frog and Toad Survey. Friends of the Rouge, University of Michigan-Dearborn, 12 pp. download the report from the Friends of the Rouge website

The Rouge River Watershed Frog and Toad Survey is a volunteer listening survey that has been coordinated by Friends of the Rouge since 1998. Volunteers are trained to recognize local frog and toad breeding calls and survey quarter-square-mile blocks within the Rouge River watershed from March through July... Drought conditions through early spring continued to make it difficult for amphibians that rely on spring ponds. Precipitation was below normal until June, yet every species was heard in a higher percentage of blocks surveyed than average. This probably reflects a bias towards surveying blocks with better habitat as volunteer interest drives what blocks are covered. ... For the fifth consecutive year, American toads were the most commonly heard species, this year in 74% of survey blocks. For the second year in a row, green frogs were the second most common at 64%. Chorus frogs, spring peepers and gray treefrogs tied for the third most commonly heard. This is good news after two years in which spring species were heard in fewer blocks...

[Species Accounts]: Western Chorus Frogs (Pseudacris triseriata triseriata) Western chorus frogs were heard in 57% of all survey blocks this year and in all seven subwatersheds. The riparian corridor along Michigan Avenue rang with the calls of these small frogs, 12 of the 12 blocks surveyed had them calling! Canton Township was also an active area for chorus frogs -- heard in 24 of 26 or 92% of surveyed blocks. Other areas with concentrations include Van Buren Township (6/7 or 86%) and Salem Township (11/13 or 85%). Spring Peepers (Pseudacris crucifer crucifer) Spring peepers were heard in 57% of survey blocks and in all seven subwatersheds. Maybury State Park and Walled Lake had the largest concentrations. All seven blocks in Superior Township had spring peepers as well as 13 of 14 blocks in Salem Township (93%) and 21 of 26 (81%) in Novi. [The Rouge River drains into the St Clair River through Detroit. Its watershed is approximately 1167 sq km and includes 48 municipalities in three counties.More than 50% of the watershed is considered urbanized with less than 25% remaining undeveloped, with a population of over 1.5 million people. There are more than 400 lakes, impoundments, and ponds in the watershed, the Rouge River itself has a total of 206 river km and is comprised of four major branches: the Main, Upper, Middle, and Lower]. from Friends of the Rouge website (return to Contents)

SURVEY AROUND JAMES BAY, ONTARIO AND QUEBEC: In James Bay Boreal Chorus Frogs Pseudacris [triseriata] maculata are at the eastern limit of their range, which extends narrowly around the shores of the Bay in the grassy border of flat land newly emerged from the Bay by isostatic rebound from the weight of the Wisconsin glaciation. In May and June of 2002 the James Bay Expedition sought Chorus Frogs around Moosonee in Ontario, and 85 km east of there at Rupert Bay in Quebec. In 1971-72 FWS had marked the southern range limit of Boreal Chorus Frogs at Store Creek in the middle of the cettlement of Moosonee, Ontario. In 2002 Chorus Frogs were not heard from the settlement of Moosonee, where many of the ditches along the streets have been filled in,.nor from the grassy-boggy clearing around the airport, where they were heard in 1972, and where the habitat still seems adequate. Chorus Frogs were heard in good numbers at Whitetop Creek, at on the west shore of the mouth of the Moose River. We found Boreal Chorus Frogs at Rupert Bay, Cabbage Willows Bay, in Quebec (taking the first Quebec specimen). The restriction of the species to barely-supratidal habitats suggests that changes to the salinity of Rupert Bay by projected hydroelectric projects may imperil the species here. -- Jean-François Desroches, Isabelle Picard, Frederick W. Schueler, and Louis-Philippe Gagnon. more about the James Bay expedition (return to Contents)

Frogs make comeback in Michigan - Large populations are good indicators of a healthy environment. DETROIT NEWS (Michigan) 11 October 2001

(AP): Green frogs may be thriving and the beleaguered leopard frog may be bouncing back in some areas, the annual state frog survey suggests, which is good news for those concerned about development taking over wildlife habitat. ...In the Ann Arbor area, based on sites surveyed for the statewide count, Mifsud sees numbers and locations of green frogs apparently on the rise. They're very adaptable to a variety of living conditions, including suburban back yards and new detention ponds, Mifsud says.

The wood frog isn't so adaptable.... Chorus frogs, spring peepers, American toads and gray tree frogs also are doing well.
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SURVEY ALONG ONTARIO HIGHWAY 7 AND SOUTH OF LAKE SIMCOE (2001): At the Chorus Frog meeting we promised to scour the vicinity of Tobermory and the rest of the Bruce Peninsula for Chorus Frogs, and the line of records along Hwy 7, and our memories of continuous Chorus Frog calling along that route in the early 1970s, inspired us with the notion that the most profitable way to get there would be to listen at as many sites along Hwy 7 where the species had been heard in the past as possible. We made waypoints of all Ontario Herpetofaunal Summary records sites for Pseudacris triseriata along Hwy 7, the maze of roads south of Lake Simcoe, and Hwy 26 west to the Bruce Peninsula, and then on the Peninsula, especially on the 5-mile Block. On the evening of 3 May 2001 we listened at 5 historic sites south of Lake Simcoe, hearing Chorus Frogs at one of these and at one other site along our route. We failed to hear any on the 5-Mile Block, and on the evening of 7 May we listened at the 9 historic sites along Hwy 7 between Peteborough and Perth, and heard Chorus Frogs at only one of them (on 3 May we'd listened ay most of these sites diurnally, without hearing any Chorus Frogs). It certainly seems like the populations in these areas have decreased, but any conclusions will depend on repeated surveys, earlier in the spring. FWS & AKS.(return to Contents)

SURVEYS of EASTERN ONTARIO: [Nature List] Re: Frogs in the far [and near] east. Message sent by F. W. Schueler on Wednesday 2 May 2001 at 12:46h.

"Laviolette, Lance (EXP)" wrote to me:
> I've listened at 50 locations at least within about 10 km of Glen Robertson since Saturday trying to find W. Chorus Frogs. While the weekend proved to be too cold (<5 C) for much calling last night was superb. Habitat ranged from wet pasture to hay field ditches to Typha marshes to reed marshes to wet woods to open ponds. The bad news is that apart from one site where there MAY be ONE male (I stress the MAY as I'm 90% sure it's another cold Leopard Frog), I have heard no W. Chorus Frogs.

* if you've got a single candidate site, the best time to listen is about 2130hr.

> The good news is that last night the air was alive with Spring Peepers. At several locations Wood Frogs were calling. Several others had my first calling Am. Toads for the year and there were a few locations where the Leopard Frogs were warm enough to sound like normal Leopard Frogs and not like Leopard Frogs on tranquilizers. I even had a couple of Gray Tree Frogs calling (again a first for this year) at one location. I'll be out a few more nights over the next couple of weeks so I'll keep listening.

* And last night I 'did' our 13 stations where we'd heard CFs in the past (but only 1996-1999), between Moose Creek, Newington Bog, and Morrisburg, and heard CFs at about half of them, and at a total (counting places where I picked up calling from the moving car) of 10 sites. So in the SW quadrat of SD&G they're still present in scattered populations (Seburns had previously heard none at 20 of Wayne Weller's 1990 stations from Long Sault to Alexandria). There were none near Moose Creek (where the original record [4 km NE] along Hwy 138 may have been an error - in any event the habitat is all being torn up and set on fire to ensure that no CFs persist) - but in Moose Creek itself there are lots of flooded fields that were vibrant with Peepers, which would have seemed ideal CF habitat - so maybe they're really absent there. between Lance, Seburns, and me, we've got pretty good coverage of a lot of 'Ontario E of Kemptville,' except for Prescott & Russell county. -- fred.
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Seburn's resurvey of Wayne Wellers 1990 sites.

Dave Seburn wrote:

12 April 2001: I think I've figured out how to survey EOnt for CF. I checked the database last night for SDG. Only about 40 records and most from Wayne Weller. He ran a transect through the area in April 1990. If we add in the sites where he heard Peepers we get 41 sites all surveyed in one night. This would be a great route to run again as we have a reliable observer, precise locality info and its been more than 10 yr. The Peeper sites allow us to see if CF have increased or decreased in their frequency distribution. I will survey the route at least once this spring. Would you happen to have the topos for east of here? Most of Wayne's points are on 31G/2.

and to the NatureList, 24 April 2001: Recently there has been a lot of speculation about the status of Chorus Frogs in Ontario in general and particularly here in Eastern Ontario. Last night Carolyn and I (along with our two-year old daughter, Dawn) set out to re-visit sites with historic records of Chorus Frogs.

We had an ideal benchmark to work from. In April 1990, Wayne Weller spent a night cruising around Stormont, Dundas and Glengarry listening for frogs. At 20 sites he heard Chorus Frogs. These sites stretched from Long Sault on the St Lawrence, northwards to County Road 43 and east towards Alexandria.

Last night, armed with our trusty GPS, a topographic map and the road map, we re-traced Wayne's trail and surveyed for Chorus Frogs at those 20 sites with Chorus Frogs in 1990. In 2001 NO Chorus Frogs were heard at any of the sites! If Chorus Frogs were still present they should have been calling. Air temperature was warm (above 15C all night) and Spring Peepers and Wood Frogs were calling. In addition, as a control for our survey we visited one site close to our home near Oxford Station that still has Chorus Frogs. Chorus Frogs were calling there at 8PM when we left and they were still calling at 2AM when we dragged our weary bodies home (Dawn slept fitfully in her carseat).

It is becoming increasingly apparent that Chorus Frogs are declining. Many questions remain. Is it just the edges of the range? Why just Chorus Frogs? And what is the cause? Succession from field to forest is unlikely to explain the apparent loss of 20 populations in just 10 years. Possibly the landscape has become so fragmented and hostile from a Chorus Frog point of view that dispersal/movement cannot occur among populations. Short-lived species are more vulnerable to stochastic events such as drought that prevent successful breeding for a year and such populations are more dependent upon metapopulation dynamics for re-colonization. As populations are lost through stochastic events, the remaining populations become even more isolated and vulnerable to extirpation. A kind of grim landscape extinction vortex. -- Cheery thoughts, Dave Seburn.
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the status of
Chorus Frog

[Boreal Rachet Frogs, Pseudacris triseriata, playing the combs]

If you know of a site or region where Chorus Frogs have persisted for a decade or more without change, have increased in abundance, or have declined or disappeared...

...please fill out the survey form to send an account of the status of the species to me for inclusion on this page. Such assessments are especially important in southern Ontario, where the species seems to have gone from "abundant" to "scattered" since the 1970s, but there haven't been concerted surveys of its status. An account of the status of the species should include the location of the centre of the region, its size, the beginning and ending years of the assessment, and an account of the evidence. What we're looking for is observers' carefully considered beliefs about the species status in a local area: either as categorical changes ("In the 1980's they used to be heard all through Hardbridge Township, but since 1997 we haven't heard any," or "We never heard any within 10km of Crampton until the new sewage lagoon was built in 1988, and since 1992 there's been a good chorus there every spring,") or long-term chanfges in the frequency with which the species is heard along auditory monitoring sites. The plans given for monitoring in 2001 are still viable and worthwhile, but since it hasn't been widely subscribed, we're going to have to harvest the opinions of as many local naturalists as possible if the status of the species is to be fairly represented. -- Fred Schueler, 8 March 2006. [Chorus Frog] [Pseudacris triseriata] [Chorus Frog]