Duck Nests Studied on Gray Lodge Refuge, Sutter Co. Calif., 1952 May 16 May 23 June 6 Nest No. No. of eggs Distance from water (feet) Height of cover (inches) Approx. time eggs were exposed (sec.) Nest temp. °C. Nest rel. humidity Ground temp. °C. Ground rel. humidity Approx. Time eggs were exposed (sec.) Nest temp. °C. Nest rel. humidity Ground temp. °C. Ground rel. humidity Approx. time eggs were exposed (sec.) Nest temp. °C. Nest rel. humidity Ground temp. °C. Ground rel. humidity Success of nest 8 9 10 24 unknown 33 29 33 22 15 36 40 * 23 65 24 61 Deserted 11 7 3 30 15 33 30 unknown 32 45 15 32 74 Deserted 13 9 50 18 unknown 34.5 26 15 38 34 Destroyed by predator. 17 5 600 30 15 31 28 15 33.5 40 15 35 56 Destroyed by predator. 18* 14 150 12 15 32 20 15 26 83 17 71 Destroyed by predator. 19 7 50 26 unknown 36 31 36 25 Destroyed by predator. 21 8 350 18 15 32 33 300 34 25 15 35 50 All hatched but one. 22 8 100 36 2400 29 31 28 31 unknown 19 42 22 65 Deserted 23* 8 20 30 unknown 32 33 15 31 45 15 30 67 Deserted 24* 13 300 18 15 34 35 Destroyed by predator. 25 10 50 72 15 34 43 Destroyed by predator. 26 5 300 12 15 34 39 15 30 70 At least 3 eggs hatched. 27 1 3 24 15 28 45 Destroyed by predator. 28 5 300 24 15 35.5 31 Deserted 31 6 150 6 15 25 75 Destroyed by predator. 32 8 30 30 unknown 28 70 All hatched Type of day clear clear 100% overcast * = Gadwall nest All others are Mallard nests ★ = Nest deserted before reading taken