Missouri’s hummingbird feeders should become busier places in the next few weeks, as additional ruby-throated hummingbirds move into our area from more northern states. The ruby-throated hummingbird is our only common hummingbird species. Note that only the mature males have the ruby throat. Our hummingbird numbers are greatest from August to late September. The number of birds that migrated north in the spring now have been augmented by the young birds that were hatched and fledged this year. As the birds move south, they will linger at nectar feeders.
Sometimes disputes arise as one hummingbird will aggressively try to defend a particular nectar feeder from all comers. That is a natural behavior that also occurs at nectar-producing flowering plants. Many birds are territorial when it comes to defending breeding and nesting sites, but hummingbirds can also be very territorial about food sources. The bird is acting in its own best interest to defend its food supply, but it can annoy humans who prefer less selfish behavior. Hanging several nectar feeders in various locations, where one feeder can’t be seen from another, can lessen the competition for a single feeder.
By Oct. 10, most ruby-throated hummingbirds have migrated south of Missouri. It doesn’t hurt anything to leave feeders out later than that and occasionally other species of migrating hummingbirds will be seen in Missouri, visiting feeders that are still out. Leaving feeders out into November might produce a sighting of an “accidental” species, like the rufous hummingbird, a western species that is occasionally seen in Missouri as late as early winter. Other "accidental" species that have been seen here include green violet-ear, black-chinned, Anna's, calliope and broad-tailed hummingbirds. Identification of these fall species can be extremely difficult due to subdued or immature plumage.
It is a myth that leaving feeders out too late will keep hummingbirds here when they should be migrating south.