We got back in the air for the waterfowl flight on Thursday, October 23, 2025. We have picked up more early migrators and even had a small push of mallards, but still fell below long-term averages for duck abundance this week. While we did see a slight increase in water level on the Illinois, our ducks, still mostly green-winged teal and northern pintail, remain congregated in freshly flooded, moist-soil areas (and a few cornfields). Total duck abundance (146,925) was observed 29% below long-term averages in the Illinois River Valley. Both mallard (-43%) and northern pintail (-17%) abundances were significantly below LTAs this week in the Illinois River. A bright spot this week was the abundance of green-winged teal. My estimate was 5% above the LTA for this river, with almost half of the increase attributed to Chautauqua NWR. We had to make an extra pass or two to feel comfortable with that particular estimate.
Although not as drastic as those witnessed in the IRV, similar trends were observed along the Mississippi River this week. Mallard (-32%), pintail (-8%), and green-winged teal (-15%) abundances were all below LTAs along this river system, ultimately leading to duck abundance being 32% below LTA this week. I got mixed reports from north zone hunters regarding their opener last week, but it sounds like central zone youth had good hunts. It’s our turn in the central zone this week.
I was getting gear ready earlier this week for our opener here in central Illinois on Saturday, and looked up in the loft at the “motion bag.” That old Roger’s bag has seen better days, and so have the 4-5 fading, shot-riddled, but somehow still working spinning wing decoys (SWD) inside.
Admittedly, I just don’t use the things anymore, and I should probably throw them out to make room for something else to collect dust in that corner. Like every blind in the flyway, our group has the “spinner” discussion every year. Is it worth it to drag them out? When do YOU think we should put them away? What happened to that baby Mojo hen’s head?! Are they still effective?
Removing all personal opinions here, there is data to suggest that spinners do, in fact, make a difference. Studies across the country have shown a strong latitudinal effect, meaning that as birds get further down the flyway, they become less susceptible. Similarly, there is a strong early-season effect of SWD but a declining effect throughout the season. Studies also show that the effectiveness of SWD is likely to be species- and age-dependent. Mallards and wigeon seem to be the most susceptible, and juveniles are much more likely to be fooled by SWD. And, yes, there has even been research on when it is more effective to use them.
The younger hunters out there may not remember, but several states and provinces in Canada banned SWD in the late 1990s and early 2000s. The concern was that SWDs were effective enough to warrant an evaluation of population-level impacts. USFWS conducted that evaluation, and SWDs were shown not to have effects on populations; as a result, many states/provinces began lifting bans in the mid-2000s.
So, the next time you’re sitting in the blind or at the local watering hole and the spinner topic comes up, just throw Caswell and Caswell 2004, Szymanski et al. 2005, Ackerman et al. 22006, or any other of the published papers at them. Unless, of course, you don’t want to use them… In that case, just say that you’re out there to eat breakfast and take sunrise pictures.
Good luck to everyone getting out this weekend. Stay safe and be excellent to one another. For more information on the survey and this week’s numbers, visit Aerial Inventories.