deception have focused on the use of false alarm calls or food calls to
exploit the behavior of other group members.
For many avian species, the winter months are difficult due to the relative scarcity of food. As a result, competition over food is more intense.
Anders Møller (1988a) noticed that great tits regularly produced alarm calls
in the absence of predators, suggesting that they might use such signals to
gain access to limited resources. To test this possibility, Møller collected
observations of alarm calling by great tits at feeding stations where food
was either concentrated or dispersed. Out of the total number of alarm calls
recorded, 63% were given in the absence of a predator. Great tits produced
such false alarm calls when the feeding stations were occupied either by
other great tits or other birds (e.g., house and tree sparrows). Specifically,
the nonfeeding great tit gave an alarm call and then flew straight toward
the feeding station. The feeding birds flew away upon hearing the alarm
call, thereby yielding access to the food station.
To determine whether both conspecifics and heterospecifics perceived
the false alarm calls as similar to the real alarm calls, playbacks were conducted. Both great tits and sparrows responded to the playbacks of real and
false alarm calls in the same way: they fled the feeding station and headed
for shelter. This suggested that real and false alarm calls carry the same
message.
Møller also found that the use of false alarm calls was contingent on
weather conditions as well as the relative dominance rank of the bird at the
feeding station. Thus, great tits produced more false alarm calls during
adverse weather conditions (e.g., snowstorms) as well as when the bird
feeding at the station was dominant; when subordinates were present at the
feeding station, dominants did not use false alarm calls but rather
approached and quietly displaced the subordinate. Further, great tits were
more likely to give false alarm calls when sparrows were present at a concentrated spread of food than at a dispersed spread of food and when the
heterospecifics were from a flocking rather than a nonflocking species;
similar results have been presented by Matsuoka (1980) working on marsh
tits and willow tits.
With respect to our definitional conditions, Møller’s results indicate that
the great tit’s alarm call is commonly given during predator detection. We
do not know, however, how often great tits make errors of predator detection, and thus we cannot assess whether the documented level of false alarm
calls is accurate. Second, the alarm call elicits a reliable flight response in
both conspecifics and heterospecifics. This claim is supported by both the
natural observations as well as the playback experiments with real and false
alarm calls. Third, individuals clearly have the flexibility to exploit the
manipulative power of the false alarm call, as evidenced by the contexts in
which they use them. Great tits certainly do not use false alarm calls reflexively. Rather, their use of false alarm calls appears to be under voluntary
control, as revealed by their sensitivity to the dominance rank of con110
W.T. Fitch and M.D. Hauser
exploit the behavior of other group members.
For many avian species, the winter months are difficult due to the relative scarcity of food. As a result, competition over food is more intense.
Anders Møller (1988a) noticed that great tits regularly produced alarm calls
in the absence of predators, suggesting that they might use such signals to
gain access to limited resources. To test this possibility, Møller collected
observations of alarm calling by great tits at feeding stations where food
was either concentrated or dispersed. Out of the total number of alarm calls
recorded, 63% were given in the absence of a predator. Great tits produced
such false alarm calls when the feeding stations were occupied either by
other great tits or other birds (e.g., house and tree sparrows). Specifically,
the nonfeeding great tit gave an alarm call and then flew straight toward
the feeding station. The feeding birds flew away upon hearing the alarm
call, thereby yielding access to the food station.
To determine whether both conspecifics and heterospecifics perceived
the false alarm calls as similar to the real alarm calls, playbacks were conducted. Both great tits and sparrows responded to the playbacks of real and
false alarm calls in the same way: they fled the feeding station and headed
for shelter. This suggested that real and false alarm calls carry the same
message.
Møller also found that the use of false alarm calls was contingent on
weather conditions as well as the relative dominance rank of the bird at the
feeding station. Thus, great tits produced more false alarm calls during
adverse weather conditions (e.g., snowstorms) as well as when the bird
feeding at the station was dominant; when subordinates were present at the
feeding station, dominants did not use false alarm calls but rather
approached and quietly displaced the subordinate. Further, great tits were
more likely to give false alarm calls when sparrows were present at a concentrated spread of food than at a dispersed spread of food and when the
heterospecifics were from a flocking rather than a nonflocking species;
similar results have been presented by Matsuoka (1980) working on marsh
tits and willow tits.
With respect to our definitional conditions, Møller’s results indicate that
the great tit’s alarm call is commonly given during predator detection. We
do not know, however, how often great tits make errors of predator detection, and thus we cannot assess whether the documented level of false alarm
calls is accurate. Second, the alarm call elicits a reliable flight response in
both conspecifics and heterospecifics. This claim is supported by both the
natural observations as well as the playback experiments with real and false
alarm calls. Third, individuals clearly have the flexibility to exploit the
manipulative power of the false alarm call, as evidenced by the contexts in
which they use them. Great tits certainly do not use false alarm calls reflexively. Rather, their use of false alarm calls appears to be under voluntary
control, as revealed by their sensitivity to the dominance rank of con110
W.T. Fitch and M.D. Hauser