A black-capped chickadee perches on a bird feeder. If feeders are not cleaned routinely, they can become a vector for diseases. Ariana van den Akker photo

I’ve been receiving a ton of questions about the mysterious illness that has been causing bird deaths in states from Pennsylvania and south. This is fortunately still not a concern here in Maine, but it served as a good opportunity to remind people to clean their feeders. That led to questions about how often and how best to clean one’s feeders, so I’ll cover that here.

First, it is important that cleaning bird feeders becomes a regular routine for anyone currently or considering putting them out. This is definitely an under-emphasized responsibility that is required of the hobby. Bird feeders create gathering places for large numbers of birds, and when unmaintained they can become a vector for diseases.

“Regular routine” is vague, right? You’ll need to consider a few factors to know when it is time to clean. In general, once every couple of weeks is probably good enough, but it is important to consider what the environmental conditions have been and how that can shorten the window before needing to clean. It is good to clean after a rain (or snow) if the seed has gotten wet, especially if your feeders don’t have good drainage (most don’t). That moisture encourages bacterial growth, as can warm temperatures, so while you might get away with cleaning every couple of weeks in the winter, it is better to go to a weekly schedule in the summer. Hummingbird feeders should be cleaned every few days.

The process will depend on the feeder, but in general a good scrub between fillings is adequate for cleaning. Discard any remaining feed inside the feeder, especially if you notice any mold growing, and always fill with fresh seeds. Cleaning can be done by brushing/scrubbing with a diluted bleach solution (10% bleach, or nine parts water to one part bleach), though some chemical-averse people prefer a vinegar solution. FeederWatch (feederwatch.org) recommends soaking for 10 minutes in the bleach solution, or an hour in a weak (50/50) vinegar solution. Whichever your route, make sure you clean any dirty particles and then allow the feeder to completely dry before filling.

As said above, bird feeding comes with a lot of responsibility. It is one of the only ways to make birds come closer to you, and while it helps them a little bit, it is really more for your enjoyment. Make sure you are not unintentionally luring them to feeders that are dirty, or in neighborhoods with outdoor cats. When in doubt, clean the feeders. You wouldn’t serve guests dinner on dirty plates (hopefully) and our backyard birds should be treated the same way.


Though the autumnal equinox is more than a month away, if you were to ask a few birds, fall started weeks ago. During spring migration, Maine hosts a handful of birding festivals to take advantage of the peak of that movement, when you can go out and see dozens of species in a single morning. Fall can be a bit different and harder to pinpoint a narrow time frame to take in the wonder of migration. I’m often asked questions like, “When should I go to Monhegan this fall?” (from my friends Don and Betsy last week), so I wanted to give a brief overview of when different species “peak” in fall.

In the spring, birds are on a race to reach their breeding grounds. The males want to get there and get established, so they can be nesting as early as possible for the greatest odds of success in a fairly short window of opportunity.

In contrast, the fall migration is quite drawn out. Some species, especially shorebirds (who mostly nest north of Maine) have such a small window for nesting that if they fail, they cannot re-nest and will instead start coming south immediately. With successful early nesters, they can start wandering as soon as their chicks have fledged.

Some songbirds will attempt multiple broods in a summer, but once breeding has stopped they can move around to where there will be less competition for food. Certain birds will also have a “post-breeding dispersal” when they’ll even wander north after nesting; basically, they’ve got the time so why not wander and prospect. Herons are a good example of this in Maine. You’ll often see great blue herons in atypical locations, and we get young yellow-crowned night-herons (which don’t nest in Maine) showing up in coastal areas every fall.

The fall migration is drawn out not just for individual species, but also because of the variable timing of all species moving through. That narrow window, from late April to early June, for spring migration gets stretched from late July through October for the same species as they turn south. Sightings of some of our longest distance migrants passing through, like shorebirds, will peak in August, while songbirds like warblers peak in mid to late September. Sparrows, most of which will overwinter in the U.S., so don’t have as far to travel, will tend to peak into the first weeks of October.

The point to all of this is that you’ve got a big window for the fall migration and can have different “peaking” species to peek at almost every week. Whether you are taking a trip to a birding “hot spot” or observing who is passing through your backyard, the fall migration is a great opportunity to observe some amazing feats. That 12-gram blackpoll warbler is about to fly nonstop for three days, covering 1,700 miles, and it is using your yard as its final fueling station before departing!

Do you have a nature question for Doug? Email questions to [email protected] and visit maineaudubon.org to learn more about bird walks, community science projects, and other programs about wildlife and habitat.