In the column “Since You Asked” in every issue of BirdWatching, Contributing Editor Julie Craves answers readers’ questions about birds and bird behavior. Here’s a question from our April 2015 issue:
I have fed birds for about 47 years in the same backyard location. Over the last several years during the month of October, all the year-round birds seem to disappear until mid-November. Where do they go? — Oliver Fleming, Ahoskie, North Carolina
Fall is a period of abundant resources: Songbirds can avail themselves of large crops of seeds, nuts, berries, and other plant foods and therefore may rely less on feeding stations. While many bird species are found in one location year-round, they often move short distances in fall and winter, so the individuals in your yard in summer may not be the same birds that spend the winter with you.
For example, all or parts of populations of American Robin, Blue Jay, chickadees, and sapsuckers may shift south most winters. One autumn, a hunter in southern Ohio shot a Mourning Dove I had banded in my southeastern Michigan yard in the summer. A Blue Jay I had banded in the winter ended up hundreds of miles east the following spring. I suspect what you are seeing is a changing of the guard among individuals of familiar species during the time of fall transition.
As for why you have noticed this phenomenon only recently, it may have to do with habitat changes on a large, landscape scale over the decades. Even more likely, it could be due to climate and weather events that influence (for better or worse) food resources either during the nesting season in areas away from you or during fall in your area. Bird movements are quite complex. You might be seeing a temporary trend or a more enduring shift in the movements of your local birds.
About Julie Craves
Julie is supervisor of avian research at the Rouge River Bird Observatory at the University of Michigan Dearborn and a research associate at the university’s Environmental Interpretive Center. She writes about her research on the blog Net Results, and she maintains the website Coffee & Conservation, a thorough resource on where coffee comes from and its impact on wild birds.