Nightjar novels

"Alice Wyndham has been plagued by visions of birds her whole life...until the mysterious Crowley reveals that Alice is an 'aviarist': capable of seeing nightjars, magical birds that guard human souls. When her best friend is hit by a car, only Alice can find and save her nightjar. With Crowley's help, Alice travels to the Rookery, a hidden, magical alternate London to hone her newfound talents. But a faction intent on annihilating magic users will...