Although this owl is most at home in mature broadleaved woodland it also occurs in coniferous forests, patches of mixed woodland, cemeteries, suburban parks and gardens holding mature trees: in fact wherever it can find an ample food supply and nesting sites. It is undoubtedly more familiar to the general public through its easily recognisable hooting call than from visual contact.
Rodents form the bulk of normal prey although birds do feature prominently in the diet of this species, especially passerine fledglings during the breeding cycle and adult birds in winter when thick snow cover makes rodents difficult to locate. Breeding success is directly linked with the three year cycle of vole productivity and in nadir seasons in areas where birds are heavily dependant on these mammals, they may not breed.
By inclination the species is a hole/cavity nester – preferably in trees, although quarry/cliff ledges, abandoned buildings are used, nest boxes enthusiastically occupied, nests of raptors, crows taken over if none of the former is available, and rarely, even holes on the ground resorted to. The clutch size is usually 2, quite often 3 occasionally 4, rarely 5 eggs.
In many instances only a single chick will reach fledging stage but in peak vole years whole broods often survive. Some adult females can be very aggressive in defence of their young especially as they near fledging. Tawny Owls are excellent parents and provide for their young right through to late summer when they finally abandon them. There is considerable mortality at this juncture as juveniles endeavour to fend for themselves.
National & Regional Status, Range
This owl is generally regarded as a widespread and common species nationally and regionally with a “Green” conservation status. There is some concern however, that the species may be in slow decline. Regionally it is one of the most intensively monitored species under the NERF umbrella with long-term studies in Northumberland, the North York Moors and Manchester RSG areas.
Tawny Owls can live to a considerable age and are also extremely sedentary by nature birds seldom moving more that a few kilometres from the natal area. This is well demonstrated by the recovery of a bird in the North York Moors that was ringed as a chick and found dead less than a mile from its birthplace 19 years and 5 months later. Amazingly, it was found by the person who ringed it!
Tawny Owls have little to worry about on the persecution front in this day and age except that the depredations of some individuals on game chicks at rearing pens can result in their illegal demise and the predation of both adults and young by Goshawks in forests is likely to prove an increasing problem. However, perhaps the most significant potential threat to the welfare of the species is that of secondary poisoning from present-day rodenticides. The Centre for Ecology and Hydrology is the leading Government body currently monitoring this situation from analysis of dead specimens.