Jones and White • NEST SURVIVAL OF SPRAGUE'S PIPIT 
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FIG. I. Effect of nest age on nest daily survival rale of Sprague’s Pipit plotted tor early (days 1-25), mid (days 45-69), 
and late (days 89-113) season nests with estimates taken from the top-ranked model [S(T + Age + C lutch Size)). The trend 
(T) variable models the season effect, while clutch si/e was held at the mean of 4.6 eggs per nest. Data were collected at 
Bowdoin National Wildlife Refuge, Montana. USA, 1997-2007. 
The mean distances to Ihe linear anthropogenic 
and natural features (Table I) varied throughout 
the study area. The minimum AIC ( . model 
(Table 2) included three non-distance variables 
that were good predictors of DSR prior to 
including the road and edge variables: T, age 
(Fig. I), and clutch size (Fig. 2). The CONCEAL 
and ORIENT covariates were considered, but did 
FIG. 2. Effect of nest age on nest daily surv ival rate of Sprague’s Pipit plotted for clutches of 1 (minimum in this 
study), 4.6 (mean clutch size in this study), and 6 (maximum in this study) eggs with estimates from the top-ranked model 
(A'(r + Age + Clutch Size)}. Season (trend 73 was taken at mid-season, days 45-69. Data were collected at Bowdoin 
National Wildlife Refuge, Montana. USA, 1997-2007. 
