![]() ![]() Sexes are somewhat different in plumage, with the female typically having more markings on the breast than the male, which usually have a clean breast. The adult Peregrine has a broad black malar mark, creating a ‘helmet’ over its head. The breast and belly are white or pale tawny-rufous with distinct, black barring. The adult Peregrine has dark slate-colored upperparts. The most well-known plumage age is the adult, so lets start with that. Peregrine Falcon’s have three distinct age classes that can easily be classified in the field juvenile, subadult, and adult. ![]() In the cases of the ‘Arctic’ and ‘Peale’s’ Peregrine, these subspecies are rare and live in very small and restricted ranges so I have left them out of this post. Luckily, the two main groups ‘American’ and ‘Eastern’ are quite similar in appearance, and so all of the following information on ageing applies to both. This has broken the species into two main groups, the ‘American’ Peregrine (an official subspecies found mostly west of the Great Plains) and the ‘Eastern’ Peregrine (not a subspecies, just a mix of lineages, found primarily east of the Great Plains).įor this post, I would like to explain how to tell the age of a Peregrine in the field based on some simple field marks. However, in the eastern United States, the birds that were released came from a mix of lineage of subspecies from all over the world. The Peregrines that were reintroduced into the western United States were true ‘American’ Peregrines captive-raised and released. Of these, the ‘American’ Peregrine is the most widespread and most commonly encountered. They are the ‘American’ Peregrine ( Falco peregrinus anatum), the ‘Peale’s’ Peregrine ( F. There are three subspecies of the Peregrine Falcon found in the United States. But until you actually get to see a Peregrine in the wild, you can never really understand how regal, sleek, and truly amazing this species really is. They also know this species as the fastest bird on Earth. The general public knows this species because of its widespread population decrease followed by decades worth of reintroduction efforts that have brought this species back from the brink. Without their efforts this research would not have been possible.The Peregrine Falcon is one of the most well-known birds on Earth. Vrettos added: "Our results suggest that the function of the malar stripe in peregrines is best explained by this solar glare hypothesis."Īssociate Professor Arjun Amar from the UCT FitzPatrick Institute, who supervised the research, said: "The peregrine falcon represents the ideal species to explore this long-standing hypothesis, because it has one of the most widespread distributions of all bird species, being present on every continent except Antarctica-it is therefore exposed to some of the brightest and some of the dullest areas around the globe".Īmar added: "We are grateful to all the photographers around the world that have deposited their photos onto websites. "The solar glare hypothesis has become ingrained in popular literature, but has never been tested empirically before," said Michelle Vrettos, an MSc student from UCT who carried out the research. Results showed that peregrine falcon malar stripes were larger and darker in regions of the world where sunlight is stronger. Researchers examined samples from 94 different regions or countries. ![]() The study involved comparing malar stripe characteristics, including width and prominence, of individual peregrine falcons, by using over two thousand peregrine photographs stored in online citizen science libraries. They then explored how these malar stripes varied in relation to aspects of the local climate, such as temperature, rainfall, and strength of sunlight. The scientists used photos of peregrine falcons from around the world posted on the web by bird watchers and scored the size of the malar stripe for each bird. The study, published in the journal Biology Letters was conducted by researchers from the University of Cape Town (UCT) and the University of Witwatersrand, South Africa. Until now, there had been no scientific study linking solar radiation levels to the dark 'eyeliner' plumage, which is common to many other falcon species. It's an evolutionary trait mimicked by some top athletes who smear dark makeup below their eyes to help them spot fast-moving balls in competitive sports. The distinctive dark stripes directly beneath the peregrine falcon's eyes, called the malar stripe or 'moustache', likely reduce sunlight glare and confer a competitive advantage during high-speed chases. Now research suggests these markings have evolved according to the climate the sunnier the bird's habitat, the larger and darker are the tell-tale dark 'sun-shade' feathers. Scientists have long speculated that falcons' eye markings improve their ability to target fast-moving prey, like pigeons and doves, in bright sunlight. ![]()
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