With around 2.5 million of them flying around North America, scientists know a lot about red-tailed hawks.But Angel, a red-tailed hawk in Knoxville, Tennessee, is getting the attention of scientists — and perhaps tugging at their heartstrings. "I was like oh my gosh, that's a leucistic red-tailed hawk, that's crazy,” Connor O'Brien, a project manager and biologist at Window to Wildlife, told WVLT of first seeing Angel.Leucistic means the partial loss of pigmentation, as opposed to albino, which refers to the absence of pigment.Those who have been monitoring Angel believe that the love of her mate may be part of the reason why she has managed to survive. Window to Wildlife, according to its website, specializes in installing wildlife cams. It's through such a camera that scientists have been observing the hawk and gaining new insights about birds with the rare condition. "Back in the early 2000s scientific conservation biologists would say that leucistic or albino animals cannot exist in the wild,” O’Brien said. “ It would be very rare for them to survive ... very much survival of the fittest nature is not kind."To observe her, O’Brien installed a camera that is focused on Angel’s nest. “Having no camouflage is just really bad, but Angel somehow's been able to thrive,” O’Brien said. “ She has been able to figure out how to hunt even though it's a bit easier for prey to see her coming."O’Brien has a theory as to how Angel has been able to survive — and it’s something of an avian love story that defies the odds. It involves her mate, who is called Tom. He’s a red-tailed hawk who has been taking care of a lot of the hunting. "She's had to rely more on her mate to help with that, especially during the nesting season,” O’Brien explained to WVLT. “Tom has become an excellent hunter, he catches significantly more than she does.”Tom, who doesn't appear to be leucistic, is also a bit of a knight in shimmering armor — keeping a hawk's eye out to protect Angel.“We have a lot of blue jays that harass the red-tail, specifically Angel when she's in the nest, and last season, every 10 seconds, blue jays would hit Angel's head all day,” O’Brien said. “But when Tom gets in the nest, the blue jays just leave them alone.”While it’s heartwarming, O’Brien says the relationship between Angel and Tom has scientific value. "Scientists don't think they can mate with their own species, because species can't identify them,” O’Brien said. “So, Angel is shifting that narrative and giving us significantly new data on leucism."According to WVLT’s reporting, Angel has produced a few offspring in the last four years.The Hawk Mountain Sanctuary says red-tailed hawks summer throughout the bulk of central and southern Canada and in the northern United States, but the birds also live in central Mexico, the West Indies and in some parts of Central America See more in the video player above.