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Evaluation of a Mallard Productivity Model

Tables

Table 1. Mallard productivity parameters under a situation with average water conditions and under five other climatological situations, as predicted by a simulation model
  Average
conditions		 Dry year Wet year Snowstorm,
3 May		 Snowstorm,
13 May		 Flood,
21 May
Nests per hen 1.97 1.18** 2.14** 2.33** 2.31** 2.11**
Nest success rate 0.12 0.13     0.12     0.08** 0.05** 0.11    
Hen success rate 0.23 0.14** 0.25     0.20** 0.13** 0.24    
Summer survival rate 0.76 0.76     0.75     0.78     0.81*   0.77    
Recruitment rate 0.42 0.24** 0.45     0.33** 0.21** 0.42    
Population change 0.94 0.84** 0.95     0.86** 0.77** 0.95    
Note: Significance level for difference from average situation, based on t-test with five simulations each of 500 hens: * P < 0.05, ** P < 0.01.

 

Table 2.  Distribution by habitat of nest initiations and successful nests in an average situation and under a simulated 21 May flood
  Percent of initiated nests Percent of successful nests
Habitat Average Flood Average Flood
Cropland 6.2 6.3 3.5 4.4
Grassland 35.6 35.0 51.8 56.3
Hayland 8.5 8.6 8.7 6.7
Odd areas 6.2 6.3 2.3 3.2
Planted cover 21.9 23.4 19.5 21.2
Right-of-way 2.6 2.4 0.5 1.2
Wetland 13.1 11.6 10.8 4.9
Scrubland and woodland 5.9 6.4 3.0 2.2

 

Table 3.  Mallard productivity parameters simulated by models without and with homing
  Results of model
Without homing With homing
Breeding population (females) 21.0 22.6
Initiated nests
Inside fence 3.5 5.9
Outside fence 35.9 34.7
Successful nests
Inside fence 1.9 3.3
Outside fence 4.2 4.5
Recruitment rate 0.537 0.633
Production (females) 11.3 14.3

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