The Canadian Field-Naturalist (E-Journal)

Two populations of the Mink Frog (Rana septentrionalis) were identified near Corner Brook Newfoundland during wider surveys for anurans on the west coast of the island. This brings to six the number of anuran species which are known to have been introduced to insular Newfoundland, with four known to be currently extant

Warkentin, Ian G.

Campbell, Christine E.

Powell, Kristin G.

Leonard, Tina D.

Castro, J. I., P. M. Bubucis, and N. A. Overstrom. 1988.The reproductive biology of the chain dogfish, Scyliorhinusretifer. Copeia 1988: 740-746.Coad, Brian W., H. Waszczuk, and I. Labignan. 1995.Encyclopedia of Canadian Fishes. Canadian Museum ofNature, Ottawa, and Canadian Sportfishing Productions,Waterdown, Ontario. viii + 928 pagesHubbs, C. L., and K. F. Lagler. 1964. Fishes of the GreatLakes Region. The University of Michigan Press, AnnArbor. xv + 213 pagesSpringer, S. 1979. A revision of the catsharks, Family Scyli-orhinidae. NOAA (National Oceanographic and Atmos-pheric Administration, NMFS (National Marine FisheriesService) Circular 422: v + 152 pagesSpringer, S., and V. Sadowsky. 1970. Subspecies of the west-ern Atlantic cat shark, Scyliorhinus retifer. Proceedingsof the Biological Society of Washington 83: 83-98.Received 31 August 2001Accepted 2 January 20042003 NOTES 477The anuran fauna of insular Newfoundland is theresult of intentional human introductions. The GreenFrog (Rana clamitans) arrived about 150 years agothrough its presumed accidental transport in shipmentsof hay from Nova Scotia to the St. John’s area (Maret1867; Johansen 1926). Between 1960 and 1966, Buckle(1971) systematically introduced the Northern LeopardFrog (Rana. pipiens), Wood Frog (R. sylvatica), ChorusFrog (Pseudacris triseriata) and American Toad (Bufoamericanus) to various locations in western Newfound-land. These anuran populations have since undergoneextensive change. Both the Northern Leopard Frog andChorus Frog apparently have disappeared (Maunder1997), but populations of the other three species arenow well established and are expanding throughout thewestern portion of the island (Maunder 1997; Powell2002). The Green Frog remains the sole occupant ofeastern portions of the island (Maunder 1997). Here wereport the discovery on the west coast of the island ofanother introduced anuran, the Mink Frog (Rana.septentrionalis).Field work was conducted in summer 2001 to assessthe distribution of anuran populations in three regionsalong the west coast of Newfoundland – the CodroyValley in the southwestern corner of the island, theDeer Lake-Stephenville region in west central New-foundland, and Gros Morne National Park on the westcoast of the island at the base of the Great NorthernPeninsula. American Toads were heard at numerouslocations in all three regions, Wood Frogs were heardthroughout the Deer Lake-Stephenville region, whileGreen Frogs were heard throughout the Deer Lake-Stephenville and Codroy Valley regions and at onelocation in Gros Morne National Park (Powell 2002).We encountered Mink Frogs at one site in the DeerLake-Stephenville region. Located along the Ring Roadof Corner Brook, 4.8 km west of the Trans CanadaHighway (48º 55.61'N, 57º 57.11'W; all positions deter-mined using a Garmin® GPS model 12 XL, OlatheKansas, USA), the site consists of a shallow pond ap-proximately 60 m long by 10 m at its widest point. Thepresence of the frogs was initially detected during day-light hours on 30 May 2001 and on a return visit laterthat day in excess of 30 Mink Frogs were counted ina 10 m2 area on one end of the pond. Additionally,Powell (2002) found 25 Mink Frog tadpoles along a10-m stretch of pond shoreline at this site on 30 June2001. Although Mink Frog adults are considered bysome to strongly resemble the appearance of GreenFrogs at the northern end of their range (Conant andCollins 1991), there are several distinctive features ofR. septentrionalis including the mink-like smell, spot-ting pattern on the legs, the extent of dorsolateral ridges,and the extreme webbing on the toes of the hind feet(Schueler 1975; Conant and Collins 1991). In combina-tion, these characteristics enabled us to distinguish MinkFrog adults from morphologically similar Green Frogs.Voucher specimens were collected and deposited at theProvincial Museum of Newfoundland and Labradorin St. John’s, Newfoundland (Provincial Museum cata-logue numbers NFM HE-119 and NFM HE-120).Species identification was confirmed through night-First Record of Mink Frog, Rana septentrionalis, from InsularNewfoundlandIAN G. WARKENTIN1, CHRISTINE E. CAMPBELL1, KRISTIN G. POWELL1, 2 and TINA D. LEONARD1, 21Environmental Science, Sir Wilfred Grenfell College, Memorial University of Newfoundland Corner Brook NewfoundlandA2H 6P9 Canada2Department of Biology, Acadia University, Wolfville Nova Scotia B4P 2R6 CanadaWarkentin, Ian G., Christine E. Campbell, Kristin G. Powell, and Tina D. Leonard. 2003. First record of the Mink Frog(Rana septentrionalis) from insular Newfoundland. Canadian Field-Naturalist, 117(3): 477-478.Two populations of the Mink Frog (Rana septentrionalis) were identified near Corner Brook Newfoundland during widersurveys for anurans on the west coast of the island. This brings to six the number of anuran species which are known to havebeen introduced to insular Newfoundland, with four known to be currently extant.Key Words: Mink Frog, Rana septentrionalis, Newfoundland, introduced species.15_117(3)Notes.qxd  6/11/04  5:04 PM  Page 477time calling surveys. At 2300 h on 14 and 15 June2001, sufficient individuals were heard to constitute achorus of indistinguishable, overlapping calls (callingindex of 3 based on the Frogwatch USA Program;www.mp2pwrc.usgs.gov/NAAMP/protocol/definitions.html#index). These frogs were calling from a locationabout 50 m across the pond from the original positionwhere they were seen during the day on 30 May 2001.Again, on the night of 21 June 2001, Mink Frogs wereheard calling from this site (4 individuals) as well asat a location 1600 m further west (48º 55.70’N, 57º58.34’ W) where two individuals were heard callingfrom a stream which runs through a fen beside theRing Road. Earlier that day (1330 h) full choruses ofMink Frogs were heard at both of these sites.Subsequently, and apart from our regular surveysites identified for the larger study, Mink Frogs alsowere heard calling at four locations along the Cook’sBrook drainage on the nights of 18 and 21 June 2001:(1) at the inflow of Cook’s Brook into the southernend of Big Cook’s Pond (3 individuals heard on 21June; 48º 51.75’N, 58º 4.81’W), (2) at the outflow ofCook’s Brook from Little Cook’s Pond (4 individualsheard 18 June, 1 individual 21 June; 48º 53.51’N, 58º3.69’W), (3) along Cook’s Brook about 900 m down-stream from Little Cook’s Pond (6 Mink Frogs and 4Green Frogs on 18 June, 2 Mink Frogs on 21 June;48º 53.78’N, 58º 3.26’W), and (4) a small pond (5 macross) near where Burnt Creek empties into Cook’sBrook and 6.3 km from the Big Cook’s Pond site (2mink frogs heard on 18 June; 48º 54.93’N, 58º 3.34’W).American Toads were heard at all locations alongCook’s Brook. This area along Cook’s Brook is about8 km distant from the Corner Brook Ring Road sites inan adjacent drainage, suggesting the possibility of atleast two initial release sites, or release and subsequenttranslocation.Mink Frogs were not detected at the other 29 ofour 30 survey sites in the Deer Lake-Stephenville reg-ion, nor at any of the 60 sites in the Codroy Valley andGros Morne National Park. All sites for the more ex-tensive survey were visited on three occasions (7-16May, 28 May – 6 June, 28 June – 6 July 2001) bothduring the day for egg mass and tadpole surveys andduring the night for calling surveys. Previous searches(Maunder 1983, 1997) did not detect Mink Frogs onthe island. Together, these data suggest that the releaseof Mink Frogs may have been recent. While sourcepopulations for past acknowledged introductions ofanurans to the west coast of the island were fromsouthern Ontario (Buckle 1971), it is possible thatMink Frogs may have been introduced from nativepopulations in Labrador. When questioned, no mem-bers of the local community admitted to introducingthis additional species.Acknowledgments Funding was provided to Kristin Powell through aUniversity Internship in Environmental Science spon-sored by Gros Morne National Park and the GrosMorne Co-operating Association; additional supportcame from Sir Wilfred Grenfell College through theEnvironmental Science Study and Travel Grants pro-gram and a Summer Undergraduate Research Award.Voucher specimens were collected under permit issuedby Leah Soper of the Newfoundland and LabradorDepartment of Forest Resources and Agrifoods; JohnMaunder provided the catalogue numbers from theProvincial Museum.Literature CitedBuckle, J. 1971. A recent introduction of frogs to New-foundland. Canadian Field-Naturalist 85: 72-74.Conant, R. and J. T. Collins. 1991. A field guide to reptilesand amphibians of eastern and central North America.Houghton Mifflin Company, Boston.Johansen, F. 1926. Occurrences of frogs on Anticosti Islandand Newfoundland. Canadian Field-Naturalist 40: 16.Maret, E. 1867. Frogs on Newfoundland. Proceedings of theNova Scotian Institute of Science 1: 6.Maunder, J. E. 1983. Amphibians of the Province of New-foundland. Canadian Field-Naturalist 97: 33-46.Maunder, J. E. 1997. Amphibians of Newfoundland andLabrador: status changes since 1983. Herpetological Con-servation 1: 93-99.Powell, K. G. 2002. Watersheds and water quality as deter-minants of anuran distribution in western Newfoundland.B.Sc. Honours thesis, Memorial University of Newfound-land, Corner Brook Newfoundland. 65 pages.Schueler, F. W. 1975. Geographic variation in the size ofRana septentrionalis in Quebec, Ontario, and Manitoba.Journal of Herpetology 9: 177-185.Received 30 July 2001Accepted 1 April 2004478 THE CANADIAN FIELD-NATURALIST Vol. 11715_117(3)Notes.qxd  6/11/04  5:04 PM  Page 478

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First Record of Mink Frog, Rana septentrionalis, from Insular Newfoundland

Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline

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First Record of Mink Frog, Rana septentrionalis, from Insular Newfoundland

Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?

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