You are welcome to join us at 8:00 pm any Friday night through the winter
at the dam in Oxford Mills,

south on County Road 18 from Kemptville, Ontario.

Contact us by phone at (613)258-3016 or 258-3107, or e-mail

Mudpuppy Night 4 February 2005

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Bishops Mills
Natural History

Eastern Ontario
Biodiversity Museum

Mudpuppies and Frogs in Winter at Night!

[January 2003]

Subject: [NatureList] Mudpuppy, Frog, and Tadpole night in Oxford Mills: -29C
Date: Sun, 19 Jan 2003 12:43:20 -0500
From: "Fred and Aleta"
Organization: Eastern Ontario Biodiversity Museum
To: Eastern Ontario Natural History List ,
Ottawa Herps List


Friday's Mudpuppy Night set a new record for amphibian species observed active at low temperatures. Fred has always said: "Mudpuppy Night in Oxford Mills: It's your only chance to see an active Amphibian when the air temperature is -26 C!" (see Schueler. 2001. The Ontario Herpetological Society News 88, and several other uses of that title) - but Friday night it was -29C and we saw three (or four if the tadpoles included both Green and Bull frogs) species swimming actively. In addition, we had a lot of good clean fun photographing the fauna, walking and jumping on the ice until it failed, falling into the creek, and becoming stiff with sheathing ice.

A number of explanations are possible for the unusually large number of frogs we're seeing this winter: 1) maybe with a dry fall they didn't come out on land to circumvent the dam, and so these that are stuck below the dam would otherwise have hopped around it (this doesn't, of course, explain the large number of tadpoles we're seeing); 2) Maybe the frogs can get up into the area where we watch them because the current is less, and they're not swept downstream; 3) maybe we're just better able to see them this winter, since the low flow makes them easier to view; or 4) all or some of the above.

Field notes of Frederick W. Schueler - 17 January 2003
Canada: Ontario: Grenville County: Oxford-on-Rideau: Oxford Mills Dam, Kemptville Creek. 31B/13, UTM 18TVE 464.5 790.5 - 44.96486N 75.67863W. TIME: 2002-2100. AIR TEMP: -29C, clear, calm. HABITAT: ice covered low-water creek@limestone flats blw old milldam, water 0C, clear. OBSERVERS: Frederick W. Schueler, Aleta Karstad Schueler, Matthew Scott. 2003/006/a, Mudpuppy Night outing with searchlight, full Moon. This is unprecedentedly low water for this season and temperature - the coldest we've ever been out for a Mudpuppy Night. NO:Mammalia tracks above dam in searchlight and full Moon. There's new snow on the ice, but no open water above the spillways. The only sign of activity on the ice of the pond is some snowed-over skating areas.

There was about 20-25 cm of snow on the ground. Above and below the bridge the creek was frozen over, with new ice since our 11 Jan outing, the deep water above the bridge was completely covered, and the spillways were sheathed with ice. Aleta got photos of 5 or 6 Necturus. Matt helped with holding the 20 cm measuring stick down beside each of them. We only did the west half of the creek because the ice was harder to remove from the shallower water on the east side.

The only open water was a narrow turbulent strip below the spillways, and a 5x4 m area over the shallowest part of the flats (10-15 cm depth). We enjoyed bending and breaking the ice upstream of the open area by standing on it, in midstream and on the west side, all the way to the spillway. Some broke in metre-scale chunks, others fragmented, and some bore down to the bottom - crushing one Rana (Green or Bull Frog) tadpole - an accident we've often feared at Mudpuppy Night, but have never had before. The ice was 2-5 cm thick - thinnest under deep snow. All the broken floes were carried downstream, and covered the entire stream below us in a jumble - by the time we were done, the 5x4 m clear area had migrated upstream to join the open strip below the dam. Matt had fun floe-hopping, just like a Newfoundland kid on a Bay.

This winter there's no significant growth of the bright green alga, Batrachospermum keratophytum, (which Paul Hamilton identifed for us in Jan 2001), and the moss Fontinalis hypnoides (identifed by Linda M. Ley in Jan 2001) is a short turf on the bedrock in midstream - which seems to have been growing, or at least becoming a more regular turf, through the winter.

The Vantage Point ledge (from which we traditionally counted Mudpuppies in the years before we began to wade) was well above water level, though too sheathed in ice and snow to measure the height. There was a 25 cm belt of frozen foam below the spillway, and some loosely floating pans embedded in it. All exposed water steamed constantly. NO:Orconectes Crayfish, and NO:Hemiptera Bugs were seen.

Afterwards we retired to the Brigadoon Restaurant, thawing our boots and beard and glasses. Matt had ice all over his little waders, and he and Fred got water down their boots as the ice broke under them at the foot of the dam.

2003/006/aa, Necturus maculosus (Mudpuppy) (herp). 33 adult, seen, photo. The only open water was a narrow turbulent strip below the spillways, and a 5x4 m area over the shallowest part of the flats (10-15 cm depth). In the centre of this area there was 1 big ca 30 cm adult Necturus in such shallow water that it raised a surface wave, and was visible in the ambient street and Moon lighting. After failing to photograph this, we broke a lot of the upstream ice away, exposing about 15 more Necturus. It was hard to keep an accurate count, since they tended to move upstream, or swim downstream, and the excitement of ice giving way underfoot tended to drive numbers out of one's mind.

We broke this ice with our weight, and the disturbance and vibrations of this may have driven some of the Mudpuppies upstream ahead of us. Two Necturus were curled under isolated stones near the Vantage Point ledge as we broke away the thin snow-covered ice, and we saw a total of 6 from the Vantage Point, though none had been visible when we first arrived and before we cleared the ice away.

Aleta photographed 5-6 of these beside a 20 cm reference bar. They seemed to be swimming unusually freely and vigourously, which made them hard to photograph. There were more large individuals than small, and none less than 20 cm long.

As we left, Matt and Fred walked across the creek below the spillways, and saw about 11 more Necturus crowded (but not caulked - note the technical terminology here) in below the ledge. There might have been more on the extreme E side, but Fred broke through the ice below the ledge and disrupted and disturbed the viewing.

2003/006/ab, Rana catesbeiana (Bull Frog) (herp). about 10 juveniles, seen, photo. ca 50 mm snout-vent length, in moss or bedrock cracks, though 1 swam vigourously. These were all of one size, and seemed edematously pillow-shaped, though of course no juvenile Bull Frog is ever slim. They were distributed fairly evenly over the bottom in the mid-stream area we cleared.

2003/006/ac, Rana pipiens (Northern Leopard Frog) (herp). about 10 adults and juveniles, seen, photo. Both adults (after-hatching-year in avian terminology), and juveniles were distributed across the strem bottom, in moss/bedrock cracks, especially in mid-stream and below the spillway. In the main flow of the spillway over the ledge, one was swimming very actively (though certainly not with an aestival degree of co-ordination), as if trying to get over the 25cm ledge.

2003/006/ad, Rana (True Frog) (herp). 20 ca larvae, seen, photo. about 60 mm total length, in moss/bedrock cracks, some swimming actively. As previously, these may have been either (or both) Rana clamitans (Green Frog) or Rana catesbeiana (Bull Frog).
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