Abstracts

Presented by Matthew J. Garrick - Email: matt.garrick@dnr.iowa.gov

Migration chronology plays an important role in the timing of waterfowl hunting seasons. The objective of this study is to investigate trends in timing of migration chronology of dabbling duck species common to Iowa. We counted ducks on waterfowl refuges weekly between the second week of September and the third week of December 1970-2009 on 26 state managed properties. Surveys were grouped to six regions of the state. Regression analysis was used to determine trends in timing of peak abundance of each dabbling duck species across survey years. There is no trend in the timing of peak mallard (P > 0.100), wood duck (P = 0.616), or blue-winged teal (P = 0.077) abundance across survey years. There is a trend toward later dates of peak abundance of green-winged teal (P < 0.001), northern pintail (P = 0.002), American wigeon (P < 0.001), and gadwall (P = 0.001). These data suggest midseason migrants appear to be migrating through Iowa later, while the timing of peak mallard abundance varies substantially from year to year, likely as a result of severe weather events.