House sparrows and house finches visit my feeders and the ground beneath them all year, the tree sparrows and dark-eyed juncos visit from late in the fall until spring. But the song sparrows aren’t normally here in winter and I see white-throats and white-crowns here only occasionally during spring and fall migration.
Yesterday two robins foraged for an hour in the tall cedar in our front yard. Friends on a bird walk recently said they saw robins. They also saw bluebirds and yellow-rumped warblers and a great blue heron. Someone called recently and told me he had a brown thrasher coming to his bird feeder. Those are all birds that should have gone south a month or two ago and shouldn’t be in northern Indiana this time of year.
I have seen a song sparrow in northern Indiana in winter before. I have seen white-crowned sparrows and a friend had one come to his feeder every day all winter one year. I have seen robins and bluebirds around or near my home in winter. I saw a brown thrasher in Indiana one winter several years ago. Seeing a song sparrow or a robin or bluebird or other bird of summer in our area is uncommon, even rare in winter, but it happens every year. However, this winter it seems as if I’ve seen more and have had more people tell me of seeing summer birds this winter than previous winters.
If I’m correct in this, and I have no personal records to show that I am, then the question is why?
It isn’t because I’m more aware of birds than previous years. That’s impossible. Nor is it, I’m sure, because other people are more aware of birds.
It isn’t because birds somehow know it’s going to be a mild winter just as a robin in northern Indiana in February or early March doesn’t mean an early spring. Birds are affected by weather. Warm weather in fall causes many to delay the start of migration and an early winter storm makes many start south early. Birds even take shelter at the approach of a storm. It’s believed they can detect changes in air pressure and thereby become aware that a storm is coming. But they can’t tell, any better than we seem to be able to sometimes, what the weather will be next week and surely not next month.
It isn’t because more people are feeding birds this winter than last though bird feed sales are up indicating either more people are feeding birds or those who do feed are putting out more feed. But the sale of bird feeders and bird seed has been increasing annually for many years.
I don’t believe it’s because of global warming. Oh, I do believe global warming is happening. It’s hard for me to think otherwise when glaciers are melting, the polar ice caps are shrinking, the average temperature of the air and the oceans have both increased, not greatly but measurably, and, this I find particularly striking, twenty of the twenty-one hottest years of record, I read, have been since 1980.
This is the time of year of Christmas bird counts, when birders go on all day quests for birds, identifying, counting and listing all the birds they see. Will those dedicated birders see more robins and bluebirds, song sparrows and white-throated sparrows and white-crowned sparrows, more yellow-rumped warblers and other birds of summer in the northern Indiana winter landscape than they saw last winter?