Q: I was watching robins in October and noticed that they seemed really aggressive, charging and chasing each other around my crabapple tree and at the birdbath. This seemed strange, with nesting season over months ago.

A: That's a good observation, and I turned to someone who really knows her robins, Laura Erickson, Duluth's premier observer of birds. Erickson noted that by October most young robins and females had migrated away, leaving adult males to spar over the ever- scarcer food resources. Also, they seem to be affected by autumn's shorter days, whose length is about as long as those in spring, which seems to inspire contention in robins. "The bossier robins might have an advantage in getting the best of what's left of the most popular fruits," Erickson said. In winter, robins enjoy the fruits of winterberry, hackberry and crabapple trees, and dogwood shrubs, among others.

Long-term view

Q: I'm confused because today [late October] two bluebirds were hanging around my nest box and taking what looked like nesting material inside. Why are they doing this now; they can't be getting ready to lay eggs, could they?

A: A number of readers have noted bluebirds checking out nest boxes just before leaving on migration, seemingly to make note of where they might like to raise their young next spring. Your sharp eyes noticed something I hadn't heard of before, bluebirds bringing in the kind of material they use in spring to build their nest. I'd guess that this pair of bluebirds wanted to cement its claim for your nest box by tucking in some grass in the fall. Still, whichever pair of birds returns the soonest to that box next year will claim it. For cavity nesting birds like bluebirds, cavities are always in short supply and the competition for inside spaces can become fierce.

Bluebirds in the snow

Q: Bluebirds were still hanging around my deck even in that late-October snowstorm. I've never seen them here this late.

A: It is startling to see bluebirds in the snow, since they're a migratory species that we associate so strongly with summer. By the time of that snowstorm, many if not most bluebirds had left the state for winter homes south of here. But a few spend the entire winter in our area every year, subsisting on berries and other fruits and drinking wherever they find open water.

Turkeys everywhere

Q: My wife asked if I'd ever hunted wild turkey, but I stopped hunting in 1965 and there were no turkeys around at that time. Now they're everywhere and I'm curious about what happened.

A: You're exactly right, back when you quit hunting there were no longer any wild turkeys in Minnesota, due to deforestation and unregulated hunting. Beginning in the early 1970s, the Department of Natural Resources began releasing wild turkeys from Missouri in southeastern Minnesota. Since then the population has steadily grown to more than 70,000 birds across most of the state, a success rate the DNR calls "phenomenal."

Duplex nesting?

Q: I knew that a pair of cardinals raised their family in my honeysuckle shrub. Now that the leaves are down, I can see two of the same kind of nests in there — do they nest this close together?

A: Cardinals aren't communal nesters, so wouldn't feel comfortable raising their youngsters so close to another active nest. What your sharp eyes noticed is the second nest of the same pair. Cardinals nest two (or more) times each summer and almost always build a new nest for the second brood. They liked that shrub and just moved next door.

Berry mystery

Q: Robins usually pick my two mountain ash trees clean of their orange berries. But this year, they took the berries off one tree and left the other alone. Can you explain?

A: My theory is that the robins gobbled up the fruit on one tree, then, feeling satiated, they wandered off to have a drink of water and maybe take a nap. Later in the day they found a different source of food and forgot about your mountain ash. With more and more robins remaining in our area for the entire winter, those leftover berries will be a treat for other robins or cedar waxwings at some point.

Note to readers

Steve Wilson of Isabella, Minn., posted the following to the Ely Field Naturalists listserv. You might watch for this kind of behavior at your own feeders:

"A while back I posted about a blue jay who collected and carried away at least 77 sunflower seeds from my feeder in a single trip, thanks to an expandable throat and upper esophagus. That bird was declared World Champion Seed Stuffer — Sunflower Category — on the admittedly flimsy evidence that nothing could be found in the scientific literature on the subject.

"Recently, though, a neighbor here, finding himself with shelter-in-place time on his hands, began counting the sunflower seeds that one of his jays was stuffing. He got to 80, but then had less stamina for counting than the jay did for stuffing and stopped counting. Without even trying, 'his' bird dethroned 'my' bird as the World Champion Seed Stuffer. One can only imagine if he hadn't stopped counting."

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society and writes about nature for local, regional and national newspapers and magazines, can be reached at valwrites@comcast.net.