specifics, current weather conditions, and whether heterospecifics are flock
or nonflock feeders.
Paralleling Munn’s results, Møller’s findings also violate the intuition that
for deception to be effective, the deceptive act must be rare: great tits
produce false alarm calls at extremely high rates. However, the great tit data
are a bit less clear than those collected on antshrikes and tanagers because
Møller only presents the overall rate of false alarm calls. Some of these calls
are given in the presence of heterospecifics and some in the presence of
conspecifics. To assess whether the rate of false alarm calls differs for
conspecifics and heterospecifics, it would be necessary to break down the
pooled data.
Møller’s results raise many fascinating questions, several paralleling those
raised for Munn’s work on antshrikes and tanagers. Specific to the biology
of great tits, however, it would be interesting to determine how often
individuals produce false alarm calls during the breeding season, when
resources are more abundant, and whether individuals are less likely to
produce such calls prior to the mating season given that they might be
deceiving a potential mate. One could test this hypothesis by making a male
extremely deceptive, playing back his alarm calls at high rates when no
predator is present, and contrasting this situation with one in which a male
is made extremely honest—play back his alarm call and simultaneously
present a hawk. Given these two male types, one could then look at differences in mate choice by females during the breeding season.
Møller (1990) followed up on his great tit work by looking at a comparable problem in barn swallows, a species that has been carefully studied
with respect to its breeding biology and the selective forces operating on
male–male competition and female choice (Møller 1988b, 1989, 1993). Like
great tits, barn swallows also give alarm calls in the absence of predators,
leading to the hypothesis that they are generating lies of commission. In
contrast to great tits, barn swallows most often produced false alarm calls
when their fertile mates left the nest area, apparently in search of extrapair copulations. Observations revealed that females engaged in extra-pair
copulations stopped upon hearing their mate’s alarm calls.
To determine whether males produce alarm calls deceptively, Møller
conducted two experiments. In the first experiment, he chased females
away from their nests in order to determine whether such departures
elicited false alarm calls in males. Females were chased away at the start of
nest building, during egg laying, and during the incubation period. When
males returned to the nest and detected the female’s absence, they rarely
gave alarm calls during the nest-building and incubation periods but produced false alarm calls on about 95% of all experimental trials in the
egg-laying period. Observations revealed that the false alarm calls were
functionally equivalent to the real alarm calls in that other swallows either
flew away or gave alarm calls. Further, whereas solitarily breeding swallows
produced a constant, low rate of false alarm calls across the breeding
3. Unpacking “Honesty”
111
or nonflock feeders.
Paralleling Munn’s results, Møller’s findings also violate the intuition that
for deception to be effective, the deceptive act must be rare: great tits
produce false alarm calls at extremely high rates. However, the great tit data
are a bit less clear than those collected on antshrikes and tanagers because
Møller only presents the overall rate of false alarm calls. Some of these calls
are given in the presence of heterospecifics and some in the presence of
conspecifics. To assess whether the rate of false alarm calls differs for
conspecifics and heterospecifics, it would be necessary to break down the
pooled data.
Møller’s results raise many fascinating questions, several paralleling those
raised for Munn’s work on antshrikes and tanagers. Specific to the biology
of great tits, however, it would be interesting to determine how often
individuals produce false alarm calls during the breeding season, when
resources are more abundant, and whether individuals are less likely to
produce such calls prior to the mating season given that they might be
deceiving a potential mate. One could test this hypothesis by making a male
extremely deceptive, playing back his alarm calls at high rates when no
predator is present, and contrasting this situation with one in which a male
is made extremely honest—play back his alarm call and simultaneously
present a hawk. Given these two male types, one could then look at differences in mate choice by females during the breeding season.
Møller (1990) followed up on his great tit work by looking at a comparable problem in barn swallows, a species that has been carefully studied
with respect to its breeding biology and the selective forces operating on
male–male competition and female choice (Møller 1988b, 1989, 1993). Like
great tits, barn swallows also give alarm calls in the absence of predators,
leading to the hypothesis that they are generating lies of commission. In
contrast to great tits, barn swallows most often produced false alarm calls
when their fertile mates left the nest area, apparently in search of extrapair copulations. Observations revealed that females engaged in extra-pair
copulations stopped upon hearing their mate’s alarm calls.
To determine whether males produce alarm calls deceptively, Møller
conducted two experiments. In the first experiment, he chased females
away from their nests in order to determine whether such departures
elicited false alarm calls in males. Females were chased away at the start of
nest building, during egg laying, and during the incubation period. When
males returned to the nest and detected the female’s absence, they rarely
gave alarm calls during the nest-building and incubation periods but produced false alarm calls on about 95% of all experimental trials in the
egg-laying period. Observations revealed that the false alarm calls were
functionally equivalent to the real alarm calls in that other swallows either
flew away or gave alarm calls. Further, whereas solitarily breeding swallows
produced a constant, low rate of false alarm calls across the breeding
3. Unpacking “Honesty”
111