Survival of Adult Female Northern Pintails
in Sacramento Valley, California
Michael R. Miller, Joseph P. Fleskes, Dennis L. Orthmeyer,
Wesley E. Newton, and David S. Gilmer
Abstract: North American populations of northern pintails (Anas acuta) declined between 1979 and the early 1990s. To determine if low survival during winter contributed to declines, we estimated winter (last week of Aug-Feb 1987-90) survival for 190 adult (after hatching yr [AHY]) female radio-tagged pintails in late summer in Sacramento Valley (SACV), California. Survival rates did not vary by winter (P = 0.808), among preseason, hunting season, or postseason intervals (P = 0.579), or by body mass at time of capture (P = 0.127). Premolt (wing) pintails (n = 10) tended to survive at a lower rate (0.622, SE = 0.178) than pintails that had already replaced flight feathers (0.887, SE = 0.030) (P = 0.091). The pooled survival (all years) estimate for the 180-day winter was 0.874 (SE = 0.031). Hunting mortality rate (0.041-0.087) and nonhunting mortality rate (0.013-0.076) did not differ among years (P = 0.332) or within years (all P > 0.149). Legal hunting (n = 7), predation (n = 4), cholera (n = 2), illegal shooting (n = 2), botulism (n = 1), and unknown cause (n = 1) accounted for all mortality. Nonwintering survival (annu. survival/winter survival = 0.748) was lower than winter survival; thus, if gains in annual survival are desired for this population, managers should first examine the breeding-migration period for opportunities to achieve increases.
Key words: Anas acuta, California, northern pintail, post-breeding, radio telemetry, survival, winter.
This resource is based on the following source (Northern Prairie Publication 0932):
Miller, Michael R., Joseph P. Fleskes, Dennis L. Orthmeyer, Wesley E. Newton,
and David S. Gilmer. 1995. Survival of adult female northern pintails in
Sacramento Valley, California. Journal of Wildlife Management 59(3):478-
486.
This resource should be cited as:
Miller, Michael R., Joseph P. Fleskes, Dennis L. Orthmeyer, Wesley E. Newton,
and David S. Gilmer. 1995. Survival of adult female northern pintails in
Sacramento Valley, California. Journal of Wildlife Management 59(3):478-
486. Jamestown, ND: Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.gov/resource/2002/npsurviv/npsurviv.htm
(Version 02APR2002).
Table of Contents
Figures and Tables
- Figure 1 -- Major waterfowl wintering regions
- Figure 2 -- Kaplan-Meier Survival Distribution
- Table 1 -- Summary statistics and analyses of variance for body mass and morphometry
- Table 2 -- Kaplan-Meier Survival Estimates
Michael R. Miller, Joseph P. Fleskes, Dennis L. Orthmeyer, and David S. Gilmer, National Biological Service, Northern Prairie Science Center, Wildlife Research Field Station, 6924 Tremont Road, Dixon, CA 95620, USA*
Wesley E. Newton, National Biological Service, Northern Prairie Science Center, 8711 37th Street S.E., Jamestown, ND 58401-7317, USA
* Present Address: National Biological Service, California Pacific Science Center, 6924 Tremont Road, Dixon, CA 95620, USA.
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