The weather remains cold and dreary as students and birds alike start to gear up for summer. While most of us have been mildly inconvenienced and slightly outraged at the abnormal weather patterns, changes in weather are a lot tougher on birds.
Birds are evolutionarily adapted to thrive in particular habitats, nest in certain types of vegetation, and feed on seasonal insects or berries. To take advantage of the times when their particular requirements will be met, bird migration and nesting is precisely timed. One of the big dangers that climate change has posed for birds is a shift in the seasonal availability of suitable resources.
A recent study took advantage of 48 million bird observations collected by a public database called eBird to detect changes in migration patterns in response to temperature. Interestingly, the study suggests that slow migrators like the red-eyed vireo (a common Arb resident) may be the most adaptable to changes in climate. The red-eyed vireo winters in South America; when it returns to breed in the East Central United States, it takes its time coming back, making stops along the way. This flight behavior allows the red-eyed to judge whether it wants to move on from a particular stop depending on the temperature. Other species that fly straight to North America from their wintering grounds may encounter a food shortage or resource scarcity once they arrive.
If you want to get out and look for bird nests, the killdeer and the red-winged blackbird are two species whose nests have been spotted this year. I decided to do some investigation of my own, and used eBird to look at peak observation periods for these birds in Rice and Dakota County. Both killdeer and red-winged blackbirds start to appear in low numbers at the beginning of March; peak killdeer arrival time is April 1st, while most red-winged blackbirds arrive about a month later. It looks like these summer residents are right on schedule.
- Marie Schaedel ’15, for the Cole Student Naturalists