<p>We will report on the findings we made using the time recorder function of an IC reocorder on 3 captive Japanese Green pigeons (1 male, 2 females) at the Tama Zoo Park Wildlife Conservation Center during the breeding season. </p><p>1)Calls are frequent for about 2 weeks during thebreeding season and gradually taper off to almost none after the desire to breed has passed (56 days after peak, 8 weeks). This appears to be due to seasonal cycle caused by the change of daytime and circadian rhythm.</p><p>2)The maximum number of “oao” calls per day (peak) were only 8 times and this indicates that the function of calls in pigeons is different from song birds.</p><p>3)Of the 3 pigeons during the entire period of 95 days, L0686 (male stood out to call in the morning (83 times, 87%). Results of calls from continuous recordings from before sunrise to sunset showed that :L0686 (male) peaked before sunrise and in the evening, L0685 (female) averaged most calls during the middle of the day. This shows that males call early in the morning and again in the evenings whereas females call mostly during the day. This may correlate to the fact that males take care of eggs incubation during the day while female do this during the night. This is consistent with the fact that parents birds never call while they are in their nests (Komatan 2003).</p><p>4)We did not take into consideration if there were any changes due to differences in light conditions on rainy, sunny or cloudy days. We did not notice any major changes in the number of calls or the starting time of calls so it is assumed that there was little influence from the light conditions.</p><p>5)L0686 (male) did not respond to the calls of L0685, however, it responded to the call of a wild pigeon in less than a minute. While the calls after the middle of July gradually decreased and only called 3 times at most during 5-hour period in the morning, it called 5 times on that morning and 5 times 2 days later and then decreased. This indicates that the pigeons call mainly during the breeding season and then only when they are excited or courting.</p><p>6)Among the calls made throughout the survey period, all calls exchanged with a wild pigeon were within the frequency range of each phrase and there were no unique calls. Unlike songbirds, aobato has turned out to have only one type of individual call. This is an indication that either the single call of the pigeons has several meanings or that they communicate by other methods.</p><p>7)There were some pigeons that continuously called after the 10th phrase (additional type). This was seen in L0686 (male) which is thought to be at least 8 years old. Of the 151 “oao” calls 8 (5.3%) were of this type. The other 2 pigeons did not have this type of repeated call. This type of added and repeated call was not related to the sex of the bird but is more seen in older pigeons occasionally.</p>