This has been a funky winter for birds around our yards, mostly because of the variable weather conditions. We dealt with the onslaught of “Where are the birds?” questions through the fall and early winter, a result of no snow and a mast year producing tons of naturally occurring food. Now that we’re starting to see snow accumulate, it is refreshing to have the questions switch from “where” to “why,” and that lead to an inquiry from Patty Peterson of Gorham this week, asking why there is an apparent increase in juncos this winter and why they are acting different than they have in the past.

Most people in Maine see dark-eyed juncos primarily in the winter, foraging along the edge of yards or at bird feeders. Their occurrence typically syncs up with the first snow, giving them the colloquial name of “snow birds.” Don’t confuse these dark-topped and white-bellied birds with a pinkish bill with their larger cousin, the snow bunting. It’s also worth noting that depending on the age of your field guide, you may also know them as “slate-colored juncos.” Juncos are, however, a year-round resident in Maine.

While the majority of their population shifts from south to north in the spring, they can be thought of as altitudinal migrants in Maine, moving to higher elevations for the nesting season. This is primarily so they can get into the spruce-dominated habitats they prefer for nesting, a habitat that we also find along the coast on peninsulas and islands. This gives juncos an interesting distribution map in the summer: they’re along the coast and up in the mountains; hikers are often more familiar with them in summer than winter.

We can look at eBird data to get a sense of where juncos are hanging out this year. eBird is a contributory science project run by the Cornell Lab of Ornithology that collects data on what birds are seen, when and where, and importantly with how much effort. Since they collect “effort” data (how long did you spend and what else did you see, or not see) we can use eBird to compare metrics like frequency and abundance.

Despite the reported dearth at feeders, there have been a load of juncos around this winter. Comparing this year to the average of the preceding decade, juncos are being reported 20% to 50% more frequently each week this year. (It is important to note that frequency is giving us a measure of what percentage of all the checklists submitted over that time included the species in question, so this accounts for the increased usage and participation in eBird.)

eBird also provides us with dynamic maps so we can compare different time periods, unlike most static maps in our field guides. These use frequency, rather than abundance, so it is difficult to say exactly how many birds are in each area, but it is pretty clear that juncos are wintering farther north this winter than several years in the past, at least looking at New England. I like using these large-scale projects to confirm (or reject) observations like this because we are way too biased toward the things we see in just our backyards.

So we know there are a bunch of juncos around right now. That leads to a fun part of Patty’s question: “We have had record numbers this year, and we see them in places we are not expecting: the sides of the road, our gutters, and our front porch.” I’ve been noticing this, and perhaps you have, too, if you’ve been driving around after a snowfall and see the birds flushing from the sides of the roads. Most of these are birds congregating around areas of earth exposed by a plow going off the pavement. The birds are taking advantage of the dirt, grass, and seeds that are surfaced. Most birds that consume seeds, and aren’t capable of removing the shell or husk, will also eat dirt and small stones, which accumulate in their gizzard and help grind up those seeds. So while they may be going after seeds on the sides of the roads, you’ll see quite a few birds going after dirt there, and even under porches, like at Patty’s.

Have you been noticing more juncos around your yard, especially since the snow has accumulated? The Great Backyard Bird Count is coming up, beginning on Feb.16, which is a great time to contribute your sightings to projects tracking birds like juncos.

Copy the Story Link