For the Birds Radio Program: Breeding Bird Survey 2007
A couple of weeks ago I did my Breeding Bird Survey for 2007. This is the 20th year I’ve done this route which runs through Brimson, northeast of Duluth. All but one or two of the years my friend Kathy Hermes has been my assistant, recording data, keeping track of where we are on the route map, and keeping me sane. We get up about 2:15 in the morning and Kathy is at my house at 3:30 to head up to my route’s first stop. I have to start counting exactly at 4:38, calling out every single individual bird I hear or see for exactly 3 minutes while Kathy records the data. Then we hop into my car and drive exactly half a mile to the second stop, and repeat the process. There are 50 stops on the route, which takes between four and a half and five hours to complete. After a few stops, my brain is usually swimming with bird songs, and it takes enormous concentration to focus on each stop anew, closing out the birds from earlier stops and noticing each bird singing at this stop. Most years there are lots of mosquitoes—sometimes so many that their buzzing literally blocks out a lot of the bird songs. One year I forgot mosquito netting and came home with my face not just covered with welts but swollen. And big army worm years are almost surreal. Instead of a soft breeze or distant cars, the background noise is the subtle but unmistakable hum of millions of caterpillars chewing on aspen leaves and the soft pattering of the droppings of millions of caterpillars falling like a gentle rain. Even counting from the middle of the road, Kathy and I have to check each other for army worms before getting back into the car each stop or our clothes and the car’s upholstery will be spotted with squished caterpillars.
But this year we had virtually no mosquitoes and no army worms. Not even a single tiny cloud obscured the clear sky, and most stops had no wind at all. We started out with a temperature of 45 which climbed to 55 by the end. In other words, we had pretty much perfect conditions, perhaps the best ever.
We usually have at least one family of Gray Jays, but they seem to be in decline. Warm weather in winter is dangerous for Gray Jays, which cache a lot of food for months, and then dip into their food stores when feeding babies in late winter and spring. The range of Gray Jays has been pretty much restricted to areas where winter temperatures seldom get above freezing. But now that winter warm spells are becoming more frequent and lasting longer, these food caches are often getting spoiled, seriously reducing successful Gray Jay reproduction.
Audubon recently made a list of once common species that are in serious decline, and the Evening Grosbeak was one of the top ones. As has been usual for the last decade, I didn’t detect a single one. I often find at least one Boreal Chickadee or Ruffed Grouse. These species are also on the list of common birds in decline, and this year I didn’t find either.
But it wasn’t all bleak. I counted 83 White-throated Sparrows, 55 Ovenbirds, 47 Red-eyed Vireos, and 43 American Robins. I didn’t have as many warblers as usual, but did have 13 species. And for the first time ever, I heard a Le Conte’s Sparrow.
No single Breeding Bird Survey provides significant information about bird numbers. Daily weather conditions can affect bird activity and how easily they are detected. Seasonal weather conditions can affect where each species is in its breeding cycle, affecting how much each species is singing. A Merlin or Sharp-shinned Hawk may have flown by just before a stop, silencing most of the birds for several minutes. Sometimes we’re at the right stop at the right time to catch a usually-quiet bird the very moment it bursts into song. Sometimes we’re not. But even if any given year’s results aren’t all that meaningful, over time with thousands of routes, patterns can be detected. The US Geological Survey is processing my data from this year along with that of all the other routes on the continent. With luck, all this work will help them not to just discern general patterns but, when data establishes that species are in trouble, to do something about it. And that is the whole point.