Night flight calls may serve as contact calls, where members call and listen for others in order to keep the flocks together. When vision fails, sound is often a good alternative means of communication.
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Principle among these is how to keep the flock together. Second, according to NOVA it is thought that some birds migrate by the stars! How freaking cool is that?īut birds that opt to migrate at night face additional challenges. First, one reason may be to avoid predatory birds such as falcons which commonly take out small, migrating birds. One reason small birds may migrate at nightīut one wonders, why would birds chose to migrate at night when they can't see? The answers might surprise you (they did me). However, over the last few decades recording technology has become increasingly affordable, allowing both the novice and expert to gain a better understanding of the migrating birds overhead. Unfortunately, it can be prohibitively expensive to to study migratory routes as scientists have historically been restricted to using expensive technology such as RADAR or geolocators. Therefore it is critical to identify and protect key habitat along the migratory routes in order to ensure the success of these species. These birds have evolved to carefully take advantage of abundant food resources at specific regions throughout their journeys. Some birds, such as the arctic tern, travel from the arctic to the arctic to antarctic twice a year. Moreover, where song is produced primarily by males and used as a territorial display, it is thought that both sexes produce night flight calls during the spring and fall migration and the purpose of the call is much more nuanced.Įach year 3-5 billion birds make the round trip migration to southern wintering grounds. However, night flight calls differ greatly in their structure, being only milliseconds in duration and orders of magnitude quieter than song. Like birdsong these calls may be used to identify species or group of species. Night flight calls, Chris tells me, are used to describe the zeeps, chips, soft whistles and other calls that are produced by migrating birds.
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