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Archived Postings

August 20, 2007 – August 26, 2007

After a few summers working at a banding station watching migratory songbirds arrive in the spring and depart in the fall, observers begin to learn the timing of migration of different species. In other words, after fiddling with the numbers and dates you can start predicting when certain species will migrate through the area. For some species you can guess almost to the day when the first one will show up. Of course, you may be off a day or two because of slight seasonal variation and weather, but it usually works quite well. The short time frame of spring makes guessing arrival dates easier. Predicting the passage of migrants in the fall is a little more difficult. This is because fall migration occurs over a much longer period of time, it is spread out, young birds move at different times than adults, and birds breeding at higher latitudes will migrate later. For example, we had originally thought we had seen the last of the Tennessee warblers and yellow warblers for this fall, but then a few showed up again during banding this past week. However unpredictable species fall migration timing may be there are several signs indicating that fall migration is progressing into its later stages. These signs are the observations of some the later migratory species that have begun to pass through the area. For instance, the first orange-crowned warblers we observed late in the week. Orange-crowned warblers usually begin their fall migration late in August after the last Tennessee warblers have been seen. American pipits, Lapland longspurs, and northern harriers have also begun their fall migratory passage. There was one bird we did catch this week that I was very unhappy to see in the nets. It was the first dark-eyed junco of the fall. In my mind, dark-eyed juncos are not supposed to begin moving through until middle of September. Juncos are late migrants and are usually one of the last species to move through during fall migration. This was one bird I did not want to see in August. Thankfully, we have only seen the one, which was still in juvenile plumage, indicating that it may have been a local breeder. Banding over the past week has been slow, giving us ample time to determine which birds are still migrating and which to still expect. Banding totals averaged only 12 birds a day. Swainson’s thrush was still the top captured species. However, a few Wilson’s warblers, a couple sharp-shinned hawks and a bay-breasted warbler kept banding somewhat interesting. Visual migration passage was at a standstill, with the exception of a single day yellow-rumped warbler migration push mid-week. Over 300 yellow-rumped warblers were counted in a few hours. Late August may mean lower banding totals, but it also means owl banding. The LSLBO started its fourth year of northern saw-whet owl banding project on August 22. Owl banding runs every night until mid-October. The number of owls banded in the past years have surprised and surpassed many expectations. 91 owls were banded in 2004, followed by 134 in 2005 and 200 in 2006. A long-eared owl was also banded in 2006, which was an amazing bird to find in the nets. As with the start of any banding project, the anticipation of what the season will bring is high. So far it is off to a good start, three saw-whets have been banded in the opening week.

2010