Laura Erickson's For the Birds

Counting

Even though shorebirds and hummingbirds have been on the wing for a while, ornithologists consider August first to be the true start of fall migration. And August is when most migration observation points start conducting their annual counts of fall migration. From the time we’re little children, we like to count. We start with “one, two, buckle my shoe” but some of us quickly progress to birds. When a long wedge of geese passes over, we automatically start counting. Eventually we move on to harder groups and become more compulsive. We try to count loose flocks of migrating Blue Jays, and then test our eyes and counting skills with swirling flocks of waxwings.

Counting a single large flock of birds can be tricky, so imagine what it’s like to count flock after flock, hour after hour. On September 18, 1993, Frank Nicoletti counted 49,615 hawks in about 10 hours of counting. Another local birder, Mike Hendrickson, counted 43,690 nighthawks migrating along the north shore during a 2 ½ hour period on August 26, 1990. And I was the counter at the Lakewood Pumping Station on October 1, 1988, the morning we counted 95,948 migrants over a 5 hour period. This count tallied 62,707 robins, 29,330 warblers, and smaller numbers of a wide variety of other species.

How is it possible to count so very many moving objects? And just how precise are those numbers? First, you never count any birds while they’re spiraling in a kettle—it would be close to impossible to get an accurate gauge of their numbers. They’re rising on a thermal or updraft that eventually reaches equilibrium with the atmosphere. Counters watch for the top of the thermal, where the hawks stream forward in a band, all moving in the same direction. With them or any flock passing through, the best thing is to find the beginning of the flock or stream, and start counting back from there. Some people manage to count by 5s or 10s accurately, but I could never master that—I go one by one. After each kettle goes by the counter records the total on a data sheet.

It’s easiest and most accurate when the counter has help. Switching back and forth between close focusing on a count sheet and distant focusing for spotting birds can make even sharp eyes miss birds, so the assistant’s first job is to record the birds so the counter can stay focused on the sky. Also, the assistant can help keep track of broad-wings after they’re counted, so as hawks stream out and form a new kettle, they won’t be recounted. As the counter sees other species in a stream of broad-wings, he or she can call them out for the assistant to record while the counter keeps counting broad-wings.

Some counters use a metal clicker to tally one species. At Hawk Ridge, the best species to “click” is the Sharp-shinned Hawk. Hundreds of sharpies can fly over in a single day, but they’re mostly flying alone or in twos or threes. Clicking each time you see one quickly becomes second nature. At the end of each hour, it’s an easy matter to give the assistant the total for the hour, reset the clicker, and start over. Other species are recorded on the data sheet as they’re seen. Because of the care in counting, a day’s count is almost certainly an under- rather than an over-estimate of the day’s migration, but it’s probably quite close to what actually flew over.

Counting hawks requires good eyes and knowledge of how to identify the many possibilities. Fortunately, Hawk Ridge has a professional naturalist to help visitors with identification and counting skills, and most of the birders hanging around there are generous with their knowledge, so even beginners can usually get plenty of pointers as they grow more proficient. If you’re planning a trip to Duluth anytime from mid-August through November, stop by the ridge. If the wind is right (usually with a westerly component) migration can be huge. But except when the wind is easterly or it’s raining, there’s always something happening at the Ridge. You can count on it.