Yesterday’s climatic drama here in MN included thunder and lightning (in the winter!), rain, freezing rain, sleet, snow, and then bright sunshine for 5 minutes before more gray drizzle. There was also a lot of wind, making outdoor activity quite uncomfortable. The birds visited the feeders frantically early in the morning, perhaps in anticipation of the weather drama soon to hit them. It was entertaining to watch the woodpeckers scramble for access to the suet feeder — I usually never see all four resident species within the space of 10 minutes.
You’ve probably noticed the order of my suet visitors seemed to be organized by size, and it certainly seems to be the case that smaller birds do yield to larger-bodied ones when both want the same resource.
But the intensity of the feeding activity observed made me wonder if precipitation that day was more of driving force, or was it the drop in temperature?? Do all birds respond the same way to these two climate variables? Well, it turns out that someone else was interested in these questions, using the data generated by Project Feeder Watch collected from backyard feeders in the northeastern U.S. by the folks at the Cornell Lab of Ornithology. And some of the results were a little surprising, summarized in the graph below.
According to the authors’ findings, Yellow-bellied Sapsuckers showed the greatest probability of increased feeder activity with decreased temperatures, but the diminutive Downy Woodpecker’s feeding activity did not change with temperature — probably because they are such regular visitors every day anyway.
Red-bellied Woodpeckers are more responsive to temperature changes than Hairy Woodpeckers, even though the two species are very similar in size, and presumably in their daily energy needs. So, perhaps this reflects differences in the two species’ reliance on backyard feeders for their total food intake?
House Finches and Cardinals are more likely to be seen at feeders when there is marked precipitation, but the House Finches, like Downy Woodpeckers don’t seem to care if it’s colder — just wetter.
It’s amazing what one can learn from observing birds at a feeder. Do these results jive with what you’ve seen at your bird feeders?