Abstract
Template and visual methods of estimating bird damage to sunflower heads were compared in a laboratory test. Both methods provided similar accuracy at low levels of loss, but the visual method was more accurate over the entire spectrum of damage levels. Loss generally was underestimated with the template method and overestimated with the visual method. There was slightly less variation among observers using the template method than among those using the visual method. Time-wise, the visual method was about three times more efficient than the template method and, overall, it appears to be the better assessment method. J. WILDL. MANAGE. 39(4):802-806 Cultivation of sunflowers as a cash crop for the oil seed, confectionary, and bird seed market has increased greatly in the United States in recent years. Maturing sunflower crops are quite vulnerable to damage by birds, especially blackbirds (Agelaius phoeniceus and Quiscalus quiscula). Guarino (1974, unpublished report, Study 45, Work Unit DF-102.3, Denver Wildl. Res. Cent., Denver, Colorado) estimated that 24 percent of the sunflower crop was lost to blackbirds in a 70-km2 area in North Dakota in 1972, and Dolbeer et al. (1974, Prog. Rep., Work Unit P-F-33.10, Patuxent Wildl. Res. Cent., Laurel, Maryland) estimated a 5 to 80 percent loss in 16, 0.8-ha fields in Ohio in 1973. Undoubtedly, future wildlife research and management efforts, such as those done with field corn (Linehan 1967, De Grazio et al. 1969, Stone et al. 1972, Stickley et al. 1972), will be directed toward documenting and reducing bird damage to sunflowers. As a baseline for these endeavors, an objective evaluation of techniques for assessing bird damage to sunflowers needs to be made. This study had two objectives: (1) to summarize data on the accuracy of a template damage-assessment method used in a field study in Ohio in 1973, and (2) to compare, in a controlled laboratory test, the accuracy and efficiency of the template method an a visual method in estimating bird damage to sunflowers. I thank W. J. Francis, C. R. Ingram, A. R. Stickley, Jr., and M. E. Laderach for assistance with laboratory and field work.
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Claims 7
Claim · model-written summary
The two methods had similar accuracy at low loss levels.
- Taxon
- Sunflowers
Helianthust0 - Outcome
- accuracye0
- Qualifier
- low levels of losse0
- Comparator
- Both methodse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both methods provided similar accuracy at low levels of loss”
t0“Sunflowers”
Claim · model-written summary
The visual method was more accurate across the full range of damage.
- Taxon
- SunflowersHelianthust0
- Outcome
- accuratee0
- Direction
- moree0
- Qualifier
- entire spectrum of damage levelse0
- Comparator
- visual methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the visual method was more accurate over the entire spectrum of damage levels”
t0“Sunflowers”
Claim · model-written summary
The template method generally underestimated loss.
- Taxon
- SunflowersHelianthust0
- Outcome
- Losse0
- Direction
- underestimatede0
- Comparator
- template methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loss generally was underestimated with the template method”
t0“Sunflowers”
Claim · model-written summary
The visual method generally overestimated loss.
- Taxon
- SunflowersHelianthust0
- Outcome
- Losse1
- Direction
- overestimatede0
- Comparator
- visual methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“overestimated with the visual method”
e1“Loss generally was underestimated with the template method and overestimated with the visual method”
t0“Sunflowers”
Claim · model-written summary
Observer variation was slightly lower for the template method.
- Taxon
- SunflowersHelianthust0
- Outcome
- variation among observerse0
- Direction
- lesse0
- Comparator
- visual methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was slightly less variation among observers using the template method than among those using the visual method”
t0“Sunflowers”
Claim · model-written summary
The visual method was about three times as time efficient as the template method.
- Taxon
- SunflowersHelianthust0
- Outcome
- efficiente0
- Direction
- moree0
- Value
- three timese0
- Comparator
- template methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the visual method was about three times more efficient than the template method”
t0“Sunflowers”
Claim · model-written summary
The authors considered the visual method the better overall damage assessment method.
- Taxon
- SunflowersHelianthust0
- Treatment
- visual methode1
- Outcome
- better assessment methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“overall, it appears to be the better assessment method”
e1“the visual method was about three times more efficient than the template method and, overall, it appears to be the better assessment method”
t0“Sunflowers”