Measuring a Long-Eared Owl Asio otus. Picture by B. D'Amicis
An owl banding station consists of transects (lines) of mist-nets and a tape recorded song of the target species broadcast all night long.
The song attracts individuals to the trapping area, thus increasing considerably the probability that they hit a mist-net and get caught.
The exact behavioral mechanism inducing transient individuals to approach the recorded song is not really clear, but the system nevertheless works.
With preliminary experiments conducted in 2002 and 2003 at the "Laguna di Orbetello" banding station we obtained capture rates of Scops Owls 16-28 times higher than the mean Scops Owl capture rate of Italian standard songbird banding stations operating passively, i.e. without the help of a broadcast song.
The best periods for capturing Scops Owls in Italy are highlighted in this graph.
Major components of the broadcasting system are:
As a matter of fact, any device capable of broadcasting continuously the recorded song (with adequate volume) is OK.
Power is a critical point: tape recorders, CD players and MP3 players work with batteries while amplifiers and loudspeakers may need a 12-Volt rechargeable battery.
In the United States and Canada, a mistnet mesh size of 30 mm is recommended for Northern Saw-Whet Owls Aegolius acadicus that are slightly larger than Scops Owls. We believe that the commonly used 19 mm and 24 mm mesh sizes work well for capturing Scops Owls. (NOTE: mesh size is measured differently in Europe and the US/Canada: 19 mm, 24 mm and 30 mm correspond to 38 mm, 48 mm and 60 mm in the US and Canada.)
At the "Laguna di Orbetello" banding station, mistnets were placed in an old field dotted with shrubs and small trees. The broadcasting device (audiolure) was placed close to the nets in a central position.
"Laguna di Orbetello" banding station, in operation in 2002 and 2003. The blue lines are mistnets, the red circle is the broadcasting device (audiolure)
Nets are open at dusk and closed at dawn and must be checked every hour or less. With strong wind or rain mistnetting must be suspended and nets closed.
Owl welfare must be of primary concern.
More detailed information on trapping methodology can be found in the Project Owlnet website.
Every Country has its own regulations concerning capture, handling and banding of wild birds. In Italy, a permit issued by INFS - Istituto Nazionale per la Fauna Selvatica (Italian Institute for Wildlife) is mandatory.
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