Territorial Owls Give the Game Away

Long-Eared Owls (pictured below by Richard T. Mills) are rarely, if ever seen. They are nocturnal, have cryptic plumage and a secretive nature. How then does one survey for the presence or absence of breeding individuals? Previous studies have relied on late summer visits, to likely nesting habitat, after dark to listen out for the begging calls of young Long-Eared Owls. The calls are described as, akin to the sound of a rusty gate closing. Using this technique, however, failed breeders are over looked. To overcome this The Raptor Conservation Project of BWI has rolled out a playback survey. This will represent the first such undertaking in the state.

The survey aims to establish breeding densities of both successful and unsuccessful pairs of Long-Eared Owls within the 10km squares surrounding the West Offaly towns of Banagher, Ferbane and Belmont (IN01, IN12 and IN02 respectively). This project also aims to assess the effectiveness of the playback technique in Ireland and to provide data on the ecological requirements of the species.

What exactly is a playback survey? The concept itself is not a new one it is used in many parts of the world, for many different and contrasting species. In essence the technique relies on the territorial nature of many species. Raptors particularly can have strong territorial tendencies. By broadcasting the calls of a con-specific, a member of its own species, it is hoped that any resident birds will respond with a corresponding call or noise of some sort. This technique finds its true value for elusive species such as our study species the Long-Eared Owl. In practise I visited each accessible 1km square, of each of the 10km squares and broadcast Long-Eared Owl calls as close as possible to the centre of each (I undertook this survey under licence from the National Parks and Wildlife Service and with the use of best scientific practices). Responses varied from one coo (the male call) to a full blown aerial barrage of coos and wing claps circling over head (a territorial behaviour of males). Females also responded, on occasion, producing a nasal sounding call.

By revisiting each of the 10km squares in late summer to listening for the begging callings of young Long-Eared Owls (below), comparisons can be made to calculate the effectiveness of this playback technique. Success with this technique for surveying Long-Eared Owls in West Offaly could prove of great importance in assessing the national population of the species.