cm:
I have the text of the excerpted results at home in a word file, minus the 50 lbs of graphs and charts. I cannot find the link. I will post the text under this thread once I make it back to the house tonight.
Hey GulfCoast
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cmducks
- Regular
- Posts: 41
- Joined: Fri Jun 29, 2001 12:01 am
- Location: Roanoke, VA (formerly from Yocona, MS)
Hey GulfCoast
Thanks!
Hey GulfCoast
Here you go, pasted from the MSword download, minus the pages and pages of graphs and charts:
Experimental Evaluation of the Effect of a Mechanical Decoy
(Moto-Duck) on Hunting Success and Waterfowl Response in California
John M. Eadie 1, Thomas G. Moore 1, 2, Joshua T. Ackerman 1, 2
1 Department of Wildlife, Fish & Conservation Biology, University of California, Davis, CA 95616
2 California Waterfowl Association, 4630 Northgate Blvd., Ste. 150, Sacramento CA 95834
EXECUTIVE SUMMARY
1. We conducted an experimental evaluation of a mechanical, rotating-wing decoy (moto-duck) to: (1) document hunting success and hunting efficiency (crippling rate) by hunters when using a moto-duck compared to that when using only traditional decoys and calls; (2) compare the species, age, sex ratio and body condition of birds shot when using and not using the moto-duck; and (3) examine the behavioral response of waterfowl to the moto-duck.
2. We used matched-pairs comparisons in 37 experimental hunts. Volunteer hunters were chosen randomly from membership lists provided by the California Waterfowl Association and from club lists provided by the California Department of Fish & Game. Within each hunt, we compared 2 decoying treatments: (1) traditional decoys and calls, and (2) traditional decoys, calls, and a single moto-duck ("goal-post" type). Starting order of the decoy treatment was determined systematically for each hunt; decoy treatments were then alternated every 30 min (moto-duck off or on) until the hunter limits were filled or 6 sampling periods were completed (3 hours total). Two volunteer hunters participated in each hunt. A trained observer was located in a concealed position outside the blind and recorded hunting success, bird behavior and harvest composition. Additional information was collected on habitat characteristics, weather, and waterfowl activity (Table 1). All hunters completed an anonymous post-hunt questionnaire documenting hunter experience, previous and current use of mechanical decoys, and personal opinion of the moto-duck.
3. Hunting success was significantly higher when the moto-duck was used (Table 2). On average, pairs of hunters shot 4.84 ducks during the 1.5 hours when the moto duck was on (3 x 30 min. sample intervals) compared to 1.73 ducks during the 1.5 hours the moto-duck was off (paired t-test, P < 0.0001), a ratio of 2.80:1. Similar results were found when birds that were crippled or sailed (not recovered) were excluded from the analysis (3.73 birds with the moto-duck on compared to 1.46 ducks with the moto-duck off, a ratio of 2.56:1).
4. The effectiveness of the moto-duck declined through the season (Table 3, Figure 2). In the early season (Oct-Nov), the total number of ducks shot (recovered and not recovered) with the moto-duck was 6.25 vs. 1.25 ducks without (ratio 6.40:1); in mid-season (Dec) this declined to 4.58 vs. 1.25 ducks (ratio 3.66:1), and by the end of the season (Jan) it was 4.35 vs. 2.29 ducks (1.90:1). In all seasons, the numbers of ducks shot was significantly higher when the moto-duck was used (all P < 0.02) (Figure 3).
5. Hunters took significantly more shots during sample intervals with the moto-duck on versus off. Shooting efficiency (birds killed per shot taken) did not differ significantly with or without the moto-duck (Table 4).
6. Significantly more birds were crippled, sailed or hit during intervals with the moto-duck on versus off (all P < 0.004; Table 4). However, the crippling rate (proportion of birds not recovered) did not differ significantly (P = 0.12). The effect of the moto-duck on the number of ducks that were shot and not recovered did not vary seasonally (Figure 4). There was a small seasonal effect on the proportion of ducks that were not recovered.
7. The moto-duck affected all species, although the magnitude of effect varied. The number of birds shot when the moto-duck was on was significantly greater than expected (equal percentage on [img]images/smiles/icon_redface.gif[/img]ff) for American wigeon (93.9% of individuals shot with the moto-duck on), northern pintail (87.5%), gadwall (76.9%), green-winged teal (72.6%) and mallard (66.1%), and was greater but not significantly so for northern shoveler (64.5%) and all remaining species combined (64.2%) (Table 5, Figure 5).
8. The relative contribution of each species to the total bag differed when the moto-duck was used; American wigeon and northern pintail were proportionally more frequent, and mallards and northern shoveler were proportionally less frequent in the bag when the moto-duck was used (Figure 5).
9. Females and males (all species combined) were affected similarly – 78.1% of females and 71.5% of males were shot with moto-duck on, both significantly greater than expected (Figure 6). The proportion of females relative to males was not significantly higher when the moto-duck was on (35.6% females : 64.6% males) versus off (28.1% females : 72.9% males) (Table 6).
10. Hatch year (HY) and after-hatch year (AHY) birds (all species combined) were also affected equally – 73.5% of HY birds and 73.5% of AHY birds were shot with the moto-duck on, both significantly greater than expected (Figure 6). The proportion of HY birds relative to AHY birds did not differ significantly when the moto-duck was on (45.6% HY) compared to when it was off (45.6% HY) (Table 7).
11. An index of body condition (body weight corrected for structural size) did not differ among birds shot with the moto-duck on versus off (Table 8).
12. The behavioral response of ducks to activity of the moto-duck was variable. There were trends for more birds to decoy within close range when the moto-duck was on, but these differences were not statistically significant (Table 9). However, significantly more flights and more passes by the blind occurred during intervals when the moto-duck was on versus off. The average minimum approach distance was slightly (< 2 m) but not significantly less with the moto-duck on.
13. Bird response changed seasonally. In early and mid-season, more birds decoyed within close range (< 40 m) and made more passes by the blind when the moto-duck was on (Figure 7). In late season, fewer birds decoyed within close range while the number of passes was still greater with the moto-duck on, but the magnitude of the difference was diminished.
14. There was a positive but non-linear relationship between the number of birds decoying within close range (<40 m) and the total number of ducks shot (recovered and not recovered) (Figure 8). At higher levels of duck activity, the relationship reached a plateau, possibly due to increasing hunter selectivity. There was considerable variation about this relationship, indicating that measures of bird response (proximity of approach) do not predict accurately the number of birds that are shot.
15. There was significant variation among hunts in many of the parameters measured (Figure 9). Two-way analysis of variance (ANOVA) indicated that the effect of the moto-duck on the total number of ducks shot was consistent among hunts (Table 10). In 29 of 37 hunts, more ducks were shot with the moto-duck on, in 4 hunts the number was equal (2 hunts with 0 ducks), and in 4 hunts more ducks were shot with the moto-duck off.
16. There was a significant effect of sample interval on hunt success. Bird activity was greater and more birds were shot in the first two 30-minute intervals (1st hour of the hunt) than in later intervals (Figure 10). For all sampling intervals, more ducks were shot with the moto-duck on than off when compared for the same interval (Figure 10) and two-way ANOVA indicated that the effect of the moto-duck on the total number of ducks shot was highly significant and consistent among sample intervals (Table 11).
17. Neither habitat (Figure 11) nor weather (Figure 12) influenced the effect of the moto-duck on the number of ducks shot. Bird activity tended to be slightly higher in natural wetland sites and more birds approached to within 40 m in the rain and fog but there was no impact of these variables on the effect of the moto-duck.
18. Volunteer hunters in the study ranged in experience from 2 to 59 years of hunting, and hunted from 4 to over 60 days per year (Figure 13). Hunting experience did not influence the effect of the moto-duck on total number of birds shot (Figure 14).
19. Opinions of mechanical decoys varied among the volunteer hunters; 8.3% were strongly opposed, 12.5% were opposed, 33.3% were neutral, 27.8% were in favor and 18.1% were strongly in favor (Figure 15). These frequencies are comparable to those reported in other surveys.
20. The number of birds shot in each hunt varied significantly with hunter opinion category. Hunters that were opposed to mechanical decoys shot more birds both with the moto-duck on and with the moto-duck off (and hence more birds overall) than did hunters who were neutral, in favor or strongly in favor (Figures 16, 17). However, in all cases, hunters in each opinion category shot more ducks when the moto-duck was used than when it was not (Figure 17); two-way ANOVA indicated that the effect of the moto-duck was consistent among opinion categories (Table 12).
21. Calling level or intensity did not influence the effect of the moto-duck on the total number of ducks shot (Figure 18). The effects of calling on the number of ducks that decoyed within close range were variable (Figure 18).
22. Many of the volunteer hunters used a dog to retrieve downed birds (31 of 37 hunts). The number of ducks that were shot but not recovered was lower in hunts with a dog, as was the proportion of ducks not recovered (Figure 19). However, the presence of a dog did not significantly influence the effect of the moto-duck.
23. Our results suggest the following conclusions:
(i) when all other factors are held constant, the moto-duck can lead to a significant increase in the number of ducks shot (overall ratio of 2.80:1);
(ii) this effect declined over the season, although it remained statistically significant in all periods;
(iii) the absolute number of birds that were crippled and not recovered was higher when the moto-duck was used, but the crippling rate (proportion of ducks not recovered) did not differ significantly;
(iv) most species of ducks, and both sexes and age classes were harvested in greater numbers when the moto-duck was used; American wigeon and northern pintail were proportionally more common, and mallards and northern shoveler proportionally less common in the bag when the moto-duck was used – these species may differ somewhat in their response;
(v) the effect of the moto-duck was not confounded by sample interval, variation among hunts, habitat, weather, hunter experience, hunter opinion, calling level or presence of a dog.
24. Our analyses consider only the effect of the moto-duck in local, controlled hunts in which extraneous variables were held constant by design. The effects of the moto-duck may be less pronounced when scaled to a larger area and when miscellaneous variables that impact hunter success are included.
********
There are still 6 other components to the studies yet to come, but these results are quite interesting, are they not?
Experimental Evaluation of the Effect of a Mechanical Decoy
(Moto-Duck) on Hunting Success and Waterfowl Response in California
John M. Eadie 1, Thomas G. Moore 1, 2, Joshua T. Ackerman 1, 2
1 Department of Wildlife, Fish & Conservation Biology, University of California, Davis, CA 95616
2 California Waterfowl Association, 4630 Northgate Blvd., Ste. 150, Sacramento CA 95834
EXECUTIVE SUMMARY
1. We conducted an experimental evaluation of a mechanical, rotating-wing decoy (moto-duck) to: (1) document hunting success and hunting efficiency (crippling rate) by hunters when using a moto-duck compared to that when using only traditional decoys and calls; (2) compare the species, age, sex ratio and body condition of birds shot when using and not using the moto-duck; and (3) examine the behavioral response of waterfowl to the moto-duck.
2. We used matched-pairs comparisons in 37 experimental hunts. Volunteer hunters were chosen randomly from membership lists provided by the California Waterfowl Association and from club lists provided by the California Department of Fish & Game. Within each hunt, we compared 2 decoying treatments: (1) traditional decoys and calls, and (2) traditional decoys, calls, and a single moto-duck ("goal-post" type). Starting order of the decoy treatment was determined systematically for each hunt; decoy treatments were then alternated every 30 min (moto-duck off or on) until the hunter limits were filled or 6 sampling periods were completed (3 hours total). Two volunteer hunters participated in each hunt. A trained observer was located in a concealed position outside the blind and recorded hunting success, bird behavior and harvest composition. Additional information was collected on habitat characteristics, weather, and waterfowl activity (Table 1). All hunters completed an anonymous post-hunt questionnaire documenting hunter experience, previous and current use of mechanical decoys, and personal opinion of the moto-duck.
3. Hunting success was significantly higher when the moto-duck was used (Table 2). On average, pairs of hunters shot 4.84 ducks during the 1.5 hours when the moto duck was on (3 x 30 min. sample intervals) compared to 1.73 ducks during the 1.5 hours the moto-duck was off (paired t-test, P < 0.0001), a ratio of 2.80:1. Similar results were found when birds that were crippled or sailed (not recovered) were excluded from the analysis (3.73 birds with the moto-duck on compared to 1.46 ducks with the moto-duck off, a ratio of 2.56:1).
4. The effectiveness of the moto-duck declined through the season (Table 3, Figure 2). In the early season (Oct-Nov), the total number of ducks shot (recovered and not recovered) with the moto-duck was 6.25 vs. 1.25 ducks without (ratio 6.40:1); in mid-season (Dec) this declined to 4.58 vs. 1.25 ducks (ratio 3.66:1), and by the end of the season (Jan) it was 4.35 vs. 2.29 ducks (1.90:1). In all seasons, the numbers of ducks shot was significantly higher when the moto-duck was used (all P < 0.02) (Figure 3).
5. Hunters took significantly more shots during sample intervals with the moto-duck on versus off. Shooting efficiency (birds killed per shot taken) did not differ significantly with or without the moto-duck (Table 4).
6. Significantly more birds were crippled, sailed or hit during intervals with the moto-duck on versus off (all P < 0.004; Table 4). However, the crippling rate (proportion of birds not recovered) did not differ significantly (P = 0.12). The effect of the moto-duck on the number of ducks that were shot and not recovered did not vary seasonally (Figure 4). There was a small seasonal effect on the proportion of ducks that were not recovered.
7. The moto-duck affected all species, although the magnitude of effect varied. The number of birds shot when the moto-duck was on was significantly greater than expected (equal percentage on [img]images/smiles/icon_redface.gif[/img]ff) for American wigeon (93.9% of individuals shot with the moto-duck on), northern pintail (87.5%), gadwall (76.9%), green-winged teal (72.6%) and mallard (66.1%), and was greater but not significantly so for northern shoveler (64.5%) and all remaining species combined (64.2%) (Table 5, Figure 5).
8. The relative contribution of each species to the total bag differed when the moto-duck was used; American wigeon and northern pintail were proportionally more frequent, and mallards and northern shoveler were proportionally less frequent in the bag when the moto-duck was used (Figure 5).
9. Females and males (all species combined) were affected similarly – 78.1% of females and 71.5% of males were shot with moto-duck on, both significantly greater than expected (Figure 6). The proportion of females relative to males was not significantly higher when the moto-duck was on (35.6% females : 64.6% males) versus off (28.1% females : 72.9% males) (Table 6).
10. Hatch year (HY) and after-hatch year (AHY) birds (all species combined) were also affected equally – 73.5% of HY birds and 73.5% of AHY birds were shot with the moto-duck on, both significantly greater than expected (Figure 6). The proportion of HY birds relative to AHY birds did not differ significantly when the moto-duck was on (45.6% HY) compared to when it was off (45.6% HY) (Table 7).
11. An index of body condition (body weight corrected for structural size) did not differ among birds shot with the moto-duck on versus off (Table 8).
12. The behavioral response of ducks to activity of the moto-duck was variable. There were trends for more birds to decoy within close range when the moto-duck was on, but these differences were not statistically significant (Table 9). However, significantly more flights and more passes by the blind occurred during intervals when the moto-duck was on versus off. The average minimum approach distance was slightly (< 2 m) but not significantly less with the moto-duck on.
13. Bird response changed seasonally. In early and mid-season, more birds decoyed within close range (< 40 m) and made more passes by the blind when the moto-duck was on (Figure 7). In late season, fewer birds decoyed within close range while the number of passes was still greater with the moto-duck on, but the magnitude of the difference was diminished.
14. There was a positive but non-linear relationship between the number of birds decoying within close range (<40 m) and the total number of ducks shot (recovered and not recovered) (Figure 8). At higher levels of duck activity, the relationship reached a plateau, possibly due to increasing hunter selectivity. There was considerable variation about this relationship, indicating that measures of bird response (proximity of approach) do not predict accurately the number of birds that are shot.
15. There was significant variation among hunts in many of the parameters measured (Figure 9). Two-way analysis of variance (ANOVA) indicated that the effect of the moto-duck on the total number of ducks shot was consistent among hunts (Table 10). In 29 of 37 hunts, more ducks were shot with the moto-duck on, in 4 hunts the number was equal (2 hunts with 0 ducks), and in 4 hunts more ducks were shot with the moto-duck off.
16. There was a significant effect of sample interval on hunt success. Bird activity was greater and more birds were shot in the first two 30-minute intervals (1st hour of the hunt) than in later intervals (Figure 10). For all sampling intervals, more ducks were shot with the moto-duck on than off when compared for the same interval (Figure 10) and two-way ANOVA indicated that the effect of the moto-duck on the total number of ducks shot was highly significant and consistent among sample intervals (Table 11).
17. Neither habitat (Figure 11) nor weather (Figure 12) influenced the effect of the moto-duck on the number of ducks shot. Bird activity tended to be slightly higher in natural wetland sites and more birds approached to within 40 m in the rain and fog but there was no impact of these variables on the effect of the moto-duck.
18. Volunteer hunters in the study ranged in experience from 2 to 59 years of hunting, and hunted from 4 to over 60 days per year (Figure 13). Hunting experience did not influence the effect of the moto-duck on total number of birds shot (Figure 14).
19. Opinions of mechanical decoys varied among the volunteer hunters; 8.3% were strongly opposed, 12.5% were opposed, 33.3% were neutral, 27.8% were in favor and 18.1% were strongly in favor (Figure 15). These frequencies are comparable to those reported in other surveys.
20. The number of birds shot in each hunt varied significantly with hunter opinion category. Hunters that were opposed to mechanical decoys shot more birds both with the moto-duck on and with the moto-duck off (and hence more birds overall) than did hunters who were neutral, in favor or strongly in favor (Figures 16, 17). However, in all cases, hunters in each opinion category shot more ducks when the moto-duck was used than when it was not (Figure 17); two-way ANOVA indicated that the effect of the moto-duck was consistent among opinion categories (Table 12).
21. Calling level or intensity did not influence the effect of the moto-duck on the total number of ducks shot (Figure 18). The effects of calling on the number of ducks that decoyed within close range were variable (Figure 18).
22. Many of the volunteer hunters used a dog to retrieve downed birds (31 of 37 hunts). The number of ducks that were shot but not recovered was lower in hunts with a dog, as was the proportion of ducks not recovered (Figure 19). However, the presence of a dog did not significantly influence the effect of the moto-duck.
23. Our results suggest the following conclusions:
(i) when all other factors are held constant, the moto-duck can lead to a significant increase in the number of ducks shot (overall ratio of 2.80:1);
(ii) this effect declined over the season, although it remained statistically significant in all periods;
(iii) the absolute number of birds that were crippled and not recovered was higher when the moto-duck was used, but the crippling rate (proportion of ducks not recovered) did not differ significantly;
(iv) most species of ducks, and both sexes and age classes were harvested in greater numbers when the moto-duck was used; American wigeon and northern pintail were proportionally more common, and mallards and northern shoveler proportionally less common in the bag when the moto-duck was used – these species may differ somewhat in their response;
(v) the effect of the moto-duck was not confounded by sample interval, variation among hunts, habitat, weather, hunter experience, hunter opinion, calling level or presence of a dog.
24. Our analyses consider only the effect of the moto-duck in local, controlled hunts in which extraneous variables were held constant by design. The effects of the moto-duck may be less pronounced when scaled to a larger area and when miscellaneous variables that impact hunter success are included.
********
There are still 6 other components to the studies yet to come, but these results are quite interesting, are they not?
-
cmducks
- Regular
- Posts: 41
- Joined: Fri Jun 29, 2001 12:01 am
- Location: Roanoke, VA (formerly from Yocona, MS)
Hey GulfCoast
Do you have the reference for the UC Davis study handy? I've not read it but would like to.
Thanks.
Thanks.
Hey GulfCoast
The results are interesting. It would be good to know 1)how the analysis compared over three or four years. Perhaps the robo will turn from a deke to a warning flag. 2)I'd also like to know the mean # of years and days per year that the hunters who opposed the robo hunted versus hunters who were for it. 3:1 is a significant difference.
Hey GulfCoast
They are still running the tests, and will do so for a couple more years, as I understand it.
It is very interesting that those hunters opposed to the moto-duck killed more ducks than those in favor of it, whether the thing was spinning or not.
I also note that more ducks were shot with the thing running than with it off, no matter what opinion about the thing any group of hunters held.
It is very interesting that those hunters opposed to the moto-duck killed more ducks than those in favor of it, whether the thing was spinning or not.
I also note that more ducks were shot with the thing running than with it off, no matter what opinion about the thing any group of hunters held.
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