September 2003





Now that the fall migration has already started for some birds, when is the best time to stop feeding hummingbirds, and if a nectar feeder (sugar water) is available, will they fail to migrate to their wintering sites?

Hummingbird migration is triggered by the photoperiod, or the number of daylight hours, not by the availability of food. Many people fear that hummingbirds will fail to migrate south if feeders are left out in the fall. This is not true. Hummingbirds will migrate when it's time to go, regardless of the presence or absence of feeders. Fall is a great time to feed birds, if you know how to attract migratory birds in addition to the permanent residents that visit your feeders year-round. The best way to feed birds is to adjust the food and feeders with each changing season. To get the latest tips on fall bird feeding, check out the DNR's Web site at or obtain a copy of " Wild About Birds: The DNR Bird-Feeding Book," which is available through the Minnesota Bookstore.
Steve Kittleson, DNR Nongame Wildlife Specialist


How does Minnesota decide the date for the waterfowl opener, season length and bag limit?

The U.S. Fish and Wildlife Service, with the help of States and Flyway Councils, decides the annual waterfowl hunting frameworks, which include the earliest opening and latest closing dates, maximum season length, and duck bag limits. For the regular duck season, these guidelines are the same for all states in the Mississippi Flyway, including Minnesota. States have the option to be more restrictive than the Federal frameworks. Minnesota typically opens the duck season on the earliest Saturday permitted by the U.S. Fish and Wildlife Service, although last year's duck season opener was delayed one week following public comment. Hunters have also been able to hunt the full season length and take the maximum bag limits allowed in most years. The DNR considers these decisions each year based mostly on the status of Minnesota's breeding duck populations.
Jeff Lawrence, DNR Wildlife Wetland Wildlife Group Leader


The warm weather that arrived in Minnesota this past spring, and stayed into the fall, has contributed to an outbreak in oak wilt. Can anything be done to protect oak trees from the disease?

Oak wilt spreads two ways - insects and through the root system. Infected red oak trees can wilt and turn brown in just a few weeks. However, the disease is much harder to identify in bur oaks and white oaks because it doesn't spread as fast; in fact, a lab culture is necessary to confirm the disease in white oak trees. Stopping oak wilt is difficult but possible. Since fresh wounds contribute to the spread of the disease, avoiding injury to oaks (pruning, etc.) between April and July will help. A technique called vibratory plow, which separates root grafts between trees, is also effective. Fungicides are another option but the chemical treatments are costly and may not be able to save already infected trees. Additional information about oak wilt and how to protect trees can be found on the DNR's Web site
Ed Hayes, DNR Forest Health Specialist