Northern Prairie Wildlife Research Center
| Table 1. Daily energy expenditure (DEE; kJ/day), daily energy required from body reserves (DERres; kJ/day), daily energy obtained from food (DERfood; kJ/day), and food intake (g dry mass/day) of individual adult male and female northern pintails from wetlands and rice fields (Rice) during a dry (1980-81) and a wet (1981-82) winter in the Sacramento Valley, California. | |||||||||||||
| Periodb | Sex | Dry winter (1980-1981) | Wet winter (1981-1982) | ||||||||||
| DEE | DERres | DERfooda | Food intake (g) | DEE | DERres | DERfood | Food intake (g) | ||||||
| Wetlands | Rice | Wetlands | Rice | Wetlands | Rice | Wetlands | Rice | ||||||
| Aug-Sep | M | 794 | 3 | 791 | 0 | 56 | 0 | 836 | 4 | 832 | 0 | 59 | 0 |
| F | 786 | 0 | 786 | 0 | 56 | 0 | 700 | 8 | 692 | 0 | 49 | 0 | |
| Sep-Oct | M | 1,003 | 0 | 1,003 | 0 | 74 | 0 | 976 | 0 | 976 | 0 | 72 | 0 |
| F | 860 | 0 | 860 | 0 | 64 | 0 | 804 | 0 | 804 | 0 | 60 | 0 | |
| Oct-Nov | M | 1,022 | 1 | 255 | 766 | 19 | 53 | 890 | 2 | 222 | 666 | 16 | 46 |
| F | 1,002 | 0 | 250 | 752 | 19 | 52 | 1,044 | 0 | 261 | 783 | 19 | 54 | |
| Nov-Dec | M | 982 | 46 | 47 | 889 | 4 | 61 | 911 | 53 | 43 | 815 | 3 | 56 |
| F | 912 | 64 | 42 | 806 | 3 | 56 | 881 | 70 | 41 | 770 | 3 | 53 | |
| Dec-Jan | M | 971 | 116 | 43 | 812 | 3 | 56 | 997 | 0 | 50 | 947 | 4 | 65 |
| F | 908 | 64 | 42 | 802 | 3 | 55 | 930 | 2 | 46 | 882 | 4 | 61 | |
| Jan-Feb | M | 1,180 | 1 | 59 | 1,120 | 5 | 77 | 1,136 | 1 | 57 | 1,079 | 4 | 74 |
| F | 998 | 0 | 50 | 948 | 4 | 65 | 956 | 1 | 48 | 907 | 4 | 63 | |
| Feb-Mar | M | 957 | 39 | 46 | 872 | 4 | 60 | 1,032 | 1 | 52 | 979 | 4 | 68 |
| F | 888 | 54 | 42 | 792 | 3 | 55 | 925 | 0 | 46 | 879 | 4 | 61 | |
| a Proportion of food energy obtained in
August-September and September-October = 100% from wetlands (diurnal); October-November
= 25% from wetlands, 75% from rice fields (nocturnal); November-March =
5% wetlands, 95% rice fields (see METHODS and
Table 2). b Assumes 30 days between monthly midpoints (e.g., Aug-Sep = 15 Aug to 15 Sep). |
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U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/popnrg/table1.htm
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