Clutches of six female snapping turtles (Chelydra serpentina) each were distributed among six incubators set at one of three constant temperatures (22.0, 25.6, and 28.6 °C) in either a wet (−100 kPa) or a dry (−500 kPa) vermiculite substrate. We tested for influences of egg mass, clutch, and incubation temperature and moisture on survival of embryos and hatchlings, on size at hatching, and on rate of post-hatching growth over 7 months. Intraclutch variation in egg mass had no effect on embryonic mortality. Mass at hatching was correlated with egg mass, but neither variable was related significantly to post-hatching survival or rate of growth. Eggs incubated at the highest temperature produced smaller hatchlings which subsequently grew more slowly than those from eggs incubated at the low and intermediate temperatures. Eggs incubated at the intermediate temperature produced larger turtles at 7 months post-hatching than did eggs incubated at the low or high temperatures. Eggs incubated in wet substrates produced larger hatchlings than those in dry substrates, but post-hatching growth rates were independent of these effects of moisture. Eggs incubated at the two extreme temperatures produced mostly females; those at 25.6 °C produced only males. Interclutch variation was significant for egg mass, mass at hatching, and survival of embryos, and was the most important influence on variation in post-hatching rates of growth. These results indicate that egg size and size at hatching may not be useful indicators of intraspecific variation in egg quality or post-hatching success in turtles, unless differences among clutches and embryonic thermal experience are also considered, particularly in relation to parental investment in the amount, quality, and apportionment of the egg's yolk.

Scats of mink (Mustela vison) and otter (Lutra canadensis) in northeastern Alberta contained different food items in different habitat types according to type of water body. Brook stickleback (Culaea inconstans) was the most frequently encountered food item in scats of both species from a drainage system dominated by lakes and for otter from a second drainage system dominated by streams. However, mink had varying hare (Lepus americanus) as their primary food item by frequency of occurrence in this latter situation and mammalian items were significantly (P < 0.01) more frequent. Otter scats contained more fish and invertebrates (P < 0.01) and fewer mammals (P < 0.01) and birds (P < 0.05) than mink scats. Both otters and mink appeared to exploit avian species to a greater degree (P < 0.01) in the lake-dominated drainage. The frequency of avain remains in otter scats was very high and probably reflected high utilization of breeding and moulting waterfowl.

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