owling
/ˈaʊlɪŋ/noun
1 US regional. The action of imitating the hooting of an owl, especially to discover the whereabouts of birds when hunting them.
2The practice of smuggling wool or sheep out of England; the trade of an owler. In early use frequently attributive, as owling trade, etc. Now historical.
3The activity of observing owls in their natural environment, especially at night.
Origin
Mid 16th century (in an earlier sense). From owl + -ing.