Our office has taken several calls in the past 3 weeks from concerned citizens asking just that, “Where did the birds go?” Usually, they have a feeder set-up and report they have no or very few visitors, which is out of the ordinary. They checked their feeders, making sure they are clean and any spoiled or wet seed has been disposed of, but still, the birds have not returned.
So, what gives?
Bird populations vary year-to year, but there are some regular causes for these seeming disappearances of birds from your yard: weather, abundance of food sources, and available habitat. These three things can vary by locality, but in general we are seeing all of these things come into play this fall.
Weather. We have set records for high temperatures this fall. Birds are less active during the heat of the day or on particularly hot days, which is why even in late spring/early summer things quiet down around noon. Check for visitors at your feeders early in the morning.
Wild Food Sources. The food we put out in feeders only represents a percentage of a bird’s total caloric intake. Like us, they need a variety of nutrients to stay healthy, and nature is providing. We are in the midst of a mast year, when trees produce more seeds and nuts than usual: acorns, beech, and hickory nuts are in abundance. Additionally, insects have flourished in the warm, dry fall-- students at the Audubon Center have been finding caterpillars in mass and a painted lady butterfly landed on someone while I was giving instructions during a program! Migratory birds are turning these calories into necessary fat to support their long journeys and residents like the Blue Jay are getting ready for the colder months ahead by caching nuts and seeds.
Habitat. One thing I ask when someone calls concerned about the decrease in birds is if they have made changes to their landscapes. Did you remove any trees or shrubs that provided necessary cover? If you didn’t, did your neighbor? Birds need plants not just for the food they may supply but also for the protection from predators they provide. You may have the best bird feeder in town, but if birds have to fly across a large open lawn to get to it, risking being seen by predators like the Sharp-shinned Hawk or your neighbors beloved cat, they might calculate that the calories they would gain are not worth it.
So, what can you do?
Report sightings. On Vermont Edition, a local radio show on Vermont Public Radio, Bridget Butler the Bird Diva was also addressing the question "Where'd the birds go?" She asked a caller to the show how he knew the numbers were lower. Did he keep a bird journal? Or better yet, did he use eBird, an online database of citizen science reported bird sightings used by several scientific organizations, including the National Audubon Society? On eBird you can keep track of your bird sightings to your yard or feeder and, over long enough time, notice trends which can put your mind at ease, or raise alarms to scientist. Explore eBird and report your sightings: http://ebird.org/content/vt/
Make your yard or balcony an oasis for birds. One thing you can do to proved more food for birds is to keep your garden a bit untidy this fall. Seed heads left on flowers, particularly native plants, will provide a food source for birds well into winter. Vegetation provides cover from predators, while native trees and shrubs support far more protein-packed insects than non-native varieties. A dramatic example: a native oak tree can host over 500 species of caterpillar whereas the imported gingko hosts fewer than 5. And feel free to put the rake away, those fallen leaves provide a layer of insulation to the soil, later decomposing and providing free compost and cover for overwintering invertebrates and amphibians. Check National Audubon Society’s Plants for Birds database to learn about the best native plants for your area.
For more information try these resources:
Audubon's Plants for Birds Program: http://www.audubon.org/plantsforbirds
Audubon's Native Plant Database: https://www.audubon.org/native-plants
Tips for Fall Yard Work: http://www.audubon.org/news/to-help-birds-winter-go-easy-fall-yard-work
The Cornell Lab of Ornithology: https://www.allaboutbirds.org/im-seeing-fewer-birds-in-my-yard-is-something-affecting-their-populations/
Vermont eBird: http://ebird.org/content/vt/
VPR’s Vermont Edition: http://digital.vpr.net/post/migration-and-more-fall-bird-show