An Eastern Screech-owl has been seen recently in its roosting cavity near Lake Harriet. The location has been shared on Facebook, although many birders regard posting owl locations to be a bad idea. Many birders and photographers have gone to the site to see the bird.
Briefly, what research has shown is that the owls can tell one owl voice from another, quickly realize they are hearing the same (recorded) voice over and over, and shut down. Repetitive use of recorded calls is non-productive — and rude. Playing the recording louder also is worthless. Owls don’t do loud.
The owl is a nocturnal creature, active at night, sleeping during the day. The owl sleeps with its eyes closed, an apparent disappointment to observers and photographers alike, moreso the latter.
Studies have shown that raptors — this bird is a raptor — succeed about once in 10 tries at capturing prey. I don’t know what this owl is eating, but lets assume it wants two of whatever. That means it must find prey and attack 20 times to maintain its necessary energy level. It is resting during the day so it can hunt successfully at night.
Some observers stood patiently and quietly, letting this owl choose its behavior. Others played recorded screech-owl calls. One bozo played his recording over and over for about 10 minutes. Some people, impatient, clapped their hands and stamped their feet to get the owl to open its eyes.
In his identification book David Sibley says this about use of recordings: “Keep the volume low, and use only occasional snippets of sound. Do not broadcast loud or continuous sound.”
He continues: “The epitome of bad playback etiquette is the birder who walks around with a device continuously and loudly broadcasting sound, or the photographer who sets up a device on continuous playback and waits for the bird to fly in. This is ineffective, unnecessary, and is the kind of playback most likely to be harmful to birds and disturbing to other birders.”
The recording in the first place stresses the target bird. It responds to what it might consider a territorial intruder. The recording stresses songbirds in the vicinity that regard the owl as a threat. And inappropriate use of recordings is an effective way to stress other birders.
There is research on owl response to recorded calls. Recordings are used — in a correct manner by professionals — to census owl populations. Knowledge of response helps create an accurate survey.
The first paper I found was titled “Accommodation of Screech-owls to playback of recorded calls.” Briefly, accommodation means the owls get used to the recorded call very quickly and stop responding.
Another paper pointed out that owls, including screech-owls, have individual voices. You can’t, but owls can tell age and sex from the calls, and can distinguish one bird from another. This might explain accommodation: the bird has heard the call before, has responded as it chose, and now ignores the repetition.
If you go visit the Lake Harriet owl and play the same recorded tape that other birders have used (and there are not that many different owl recordings), if you’ve done this, you are paddling upstream. The owl likely chose to ignore that particular call days ago.
The owl in question, by the way, eventually tired of rude behavior and flew to find a quieter place to sleep.
Birders who observe inappropriate use of bird-call recordings should ignore Minnesota nice, and tell the offender to stop. If the bird gives you pleasure, you owe it something.