Laura Erickson's For the Birds

Pine Warbler

Of all the warblers in North America, the only one whose breeding range and wintering range fall almost entirely in the United States is the Pine Warbler. These yellow birds with their bluish gray wings and white wingbars both nest and winter in the piney areas of the southeastern states, and also nest in pines in the northern tier of eastern states. Up until this week, the only times I’ve ever seen Pine Warblers in November I’ve been in Florida, not Minnesota. But yesterday I was gazing out the window above my desk when what to my wondering eyes should appear but a Pine Warbler, munching on my suet. I was completely taken aback, not even recognizing it at first, but it came back several times throughout the afternoon, allowing me to not only verify its identity but to take lots of photos.

In spring and summer, Pine Warblers are pretty much entirely centered on Pine Trees. They are common breeders in the virgin pines on Big Pete Road in Port Wing, Wisconsin, and there are usually one or two on my breeding bird survey in the Brimson area, always in big pines. One June morning I was leading a field trip on Park Point in Duluth when I heard a singing male in the pine trees on the dunes by the recreation area. That poor guy apparently didn’t realize that the migrant hawks constantly flowing along Park Point, as well as nearby nesting Merlins, pose a clear threat that makes even those females who migrate along the point shy away from it when they’re considering nesting places. So this guy was singing his heart out the entire day, but simply couldn’t interest a female.

The Pine Warbler at my feeder, who looked like a male, wasn’t singing, and wasn’t anywhere near a pine tree. He was entirely focused on food, and being new in the neighborhood was hanging out with the chickadees the way many little songbirds do in unfamiliar territory. A chickadee flock knows all the good feeding spots in a large area, and any birds hanging out with them have an easy time discovering good food sources. This warbler seemed focused on my suet, maybe having some experience with suet cages in the past. My chickadees spend way more time in the mealworm feeders right next to my suet than on the suet. They caught the warbler’s interest, and he did drop into the mealworm feeder once, but unfortunately, that was right after a chickadee had flown off with the very last mealworm, so the little warbler couldn’t figure out what the big deal was and zipped back to the suet. I ran to the basement to replenish the mealworm supply, but didn’t see him back in that feeder all day.

November is an ominous time for warm-blooded insectivores in north country, so I don’t know how long this little guy is going to stick around. There is some variation in individual birds’ migratory instincts. This bird looks like an adult, which means he’s survived at least one winter before this one. He may still be headed south, just later than most of his kind, or he may simply not have a very powerful migratory urge. Some people think feeders entice birds to remain north when otherwise they’d head south, but that’s simply not true. Migratory birds usually fly south during the time when food is most abundant for their kind, since it is the abundant food that fuels their migration. If this little warbler decides to spend the winter, it will be because his instincts are just different from other Pine Warblers. This kind of variation helps a species—if warming trends make winters too hot or dry in the south, and not too severe in the north, it will be the birds who stay north who ultimately survive. This little Pine Warbler may be gone today, or may stick it out. It’s impossible for me to predict, but as long as he’s visiting my yard, I’ll make sure he has plenty of food and happy chickadees to keep him company.