Reports of fruit-eating birds have seen an uptick in recent days. We first started seeing them ourselves several weeks ago, when a small flock of about 25 cedar waxwings landed in the ornamental crab apple trees in a small park in downtown Gardiner.

The numbers grew daily so that by the end of the week a bustling flock of over 100 were jostling for the dark, red fruits. American robins appeared about the same time in apple trees across the road from our son’s school, as well as near the offices of the Natural Resources Council of Maine, a few blocks from the State House. Perhaps Gov. Paul LePage noticed those that we saw dining in the trees on the lawn of the Blaine House.

Wait — robins in winter? Eating ... fruit?

Perhaps this is what you’re thinking, and the answer to both is “yes.” Robins and waxwings are actually not as uncommon in winter as you might think. While the majority of their populations head south to warmer climes for the winter, decent numbers stick it out here with us.

During these cold months, with earthworms and other spring and summer delectables deep beneath the frozen ground or otherwise unavailable, robins turn to fruit-bearing trees for their meals. The apparent increase in the numbers of robins being seen around the state in the last few weeks may be because robins that were wintering farther north ate up local food sources and began moving southward to find more.

Sometimes people will speak of the winter arrival of “Newfoundland” robins, which are claimed to be darker backed and with a richer breast color than our summer robins. The best current research, though, suggests that while birds from farther north, including Newfound and Labrador, tend to be darker backed with less white on the throat, some birds that nest in our region can also show these features. Thus it’s not possible to say with any certainty where the robins that we see in winter have come from.

Cedar waxwings, on the other hand, are even greater wild cards. They can show up anytime, anywhere — they are, literally, nomads. And when it comes to wintry meals, look for the nearest crab apple or other fruit-bearing tree or bush. Their cousins, the larger Bohemian waxwings with their rufous undertails, breed across northern Boreal Canada from Manitoba west to Alaska (they may breed sparingly farther east but this is poorly documented). They move east for the winter. A few are around this winter but not in the large numbers we had in Maine a few winters ago.

For birders, the surprise is not in seeing these species in winter (though it sure is fun to hear the uninitiated exclaim that “spring is coming” because “I saw my first robin.”) What we, at least the two of us, enjoy is the notion of how these birds find the trees.

Scientists have long known that birds have memories — how else to explain the blue jay that finds the cache of seeds it stole from your feeder, days earlier? Are the robins that we see at an apple tree today individuals that had visited the area sometime in the past few years and remembered the locations of the best fruit-bearing trees? Does one waxwing flock move around looking and listening for other waxwing flocks that have already found a food source so they can join in until it’s gone. Do they break up into smaller groups after the food is exhausted and search independently until a new food source is discovered?

These are questions we find ourselves asking as we see these fruit eaters in winter. If you haven’t seen them for yourself yet, keep your eyes and ears in tune to the nearest fruit-bearing tree.