This maintains the heat transfer between steam and liquid to a maximum. Figure 3 shows a temperature profile when saturated steam is used. The difference with the previous diagram is that there is now a layer of condensate on the heating surface and steam temperature is constant.
As a general rule Owls are monogamous - pairs are comprised of one male and one female, neither one of which has any involvement with other nesting birds. With some Owl species the pair bonds last only for the duration of the breeding season, especially if the species involved is dispersive or migratory.
Owls hoot for the same reason all animals vocalize: in order to communicat. In this instance, owls which make a hooting noise do so to communicate with other owls.