Communication Theories - Soundscape Ecology: Principles, Patterns, Methods and Applications - page 71

Fig. 4.3 Experimental design to test the female latency of great tit ( Parus major ) from the
playback of mate's song ( doubled-lined box ) and of stranger mate ( single rectangle ) and female
at a distance away from the nesting box ( p ). ( a ) Playback of the stranger male precedes playback
of mate. ( b ) Playback of the mate precedes playback of stranger. The latency of response of female
great tits to playback of male song during incubation is shown (Reproduced with permission from
Lind et al. 1996 )

Territorial birds and vocal mammals can use auditory cues to evaluate the
distance at which another conspecific is calling or singing. This attitude is defined
as “ranging.” Ranging capacity is reduced by many physical and behavioral
elements.
When a bird listens to another individual of the same species, singing or
produces an immediate reaction of alert if the signal is close, or if the signal is
distant it can be ignored. The signal changes characteristics for effects of amplitude
variation and environmental degradation according to distance.
One disputed issue regards the capacity to react to the signal according to a
learning or instinctive process.
This concept opens a wide vista on this aspect of communications. Some species
of birds seem to have an innate capacity to distinguish the distance of conspecific
signals and to behave accordingly. For instance, the young of the Carolina wren
( Thryothorus ludovicianus ) prefer to cope with undegraded exemplars (Morton
et al. 1986 ). The learning mechanism is associated with memory; an experience
on a specific stimulus is preserved as a memory.
A probable recent experience is considered as familiarity. If a subject is tested
with a familiar stimulus without apparent responses, there are good reasons to
consider such stimulus is not included in the learning mechanism.
To formulate correctly the “ranging hypothesis” it is important to investigate if
the ranging process is learned or innate. In fact, this author has proposed that a bird