It is well known that many of our songbird species, including warblers, thrushes, and sparrows, are nocturnal migrants. After a long night of flying, birds often land in a place where food and safety are available. Sometimes a desired habitat is directly below where the birds are flying. Other times, a bird needs to keep flying to find suitable habitat. This phenomenon, known as redirected migration, or “morning flight”, can be observed after a night of heavy migration.
Along the coast of Cape May, New Jersey, birds that fly over land at night occasionally end up over the water. Because they are uncomfortable over the open ocean, they fly back the way the came, which brings them back to land. Since the cape sticks out into the water, this is often the first land the birds encounter, so they fly towards it and take cover. At Higbee’s Beach Wildlife Management Area in Cape May, a count of these morning flight birds is conducted every fall. In an area like Pennsylvania, a smaller number of birds also engage in redirected migration, but the reason behind it is unknown. There is no ocean to account for birds to be heading west, but they tend to fly that direction anyway.
Although we may not be able to understand the motives behind morning flight, it provides an excellent opportunity for birders to find unusual species. Unlike finding birds on the ground, birds in flight are not confined to specific habitats. For example, on September 9, 2010, I observed a Red-breasted Nuthatch, a Hooded Warbler, and several Bobolinks in morning flight over the course of a few minutes. Normally, these birds would be in very different habitats and would not be found together. Another interesting aspect of watching birds in flight is that the density of migrants is usually much higher than in the trees. On a good morning flight day, it is not uncommon to see at least three times as many warblers in flight than on the ground.
I have observed birds in morning flight over almost every location where I have paid attention, so look (and listen!) to the sky for these migrant songbirds as they fly over after dawn.
The only downside to watching birds in flight is that identification can be very difficult. Usually the birds fly past very quickly, the lighting is often terrible, and the only vocalizations are short call notes. Although it may seem daunting, the identification of birds in flight is an excellent opportunity to challenge any birder’s skills.