Finally, the only breeding case of the Hawk Owl (Surnia ulula
) in the period in Estonia was confirmed in 1893 (Leibak et al., 1994)--a top year.
Deaths at the Owl Foundation property during a WNV outbreak (July 26-September 28, 2002) and results of real-time RT-PCR on tissues from dead birds (a) Species At risk Died Tested Snowy Owl (Bubo scandiacus) 20 20 11 Northern Hawk Owl (Surnia ulula
) 26 26 17 Great Gray Owl (Strix nebulosa) 27 27 23 Boreal Owl (Aegolius funereus) 11 11 11 Northern Saw-whet Owl (Ae.
Slightly smaller than an American crow, the northern hawk owl (Surnia ulula
) is a striking, day hunting owl which constantly searches for prey from a high perch.
Unlike these two owls, the northern hawk owl (Surnia ulula
), a diurnal species, waits on the high branches of trees for prey to pass below.
Other species of Low Arctic raptors having similar diets and numerically similar breeding density responses to prey abundance, such as northern hawk-owl (Surnia ulula
), long-eared owl (Asio otus Linnaeus), and short-eared owl (Asio flammeus), have been shown to immigrate into areas of high prey abundance to nest (Korpimaki and Norrdahl, 1991; Virkkala, 1992).