We conducted researches on the call of a young Japanese Green Pigoen (less than 1 year old at the start of the survey) in captivity at the Gyotoku Bird Observation Center in Ishikawa City, Chiba Prefecture. Using an IC recorder with Ðimer recording function we were able to analyze the number of and changes in the calls of Japanese Green Pigeons (born in the previous year) during their first breeding season.

1)The maximum frequency of each phrase of the Japanese Green Pigeons 1 year after birth is low when they first began to call. And the frequency becomes into standard voice pitch thereafter but it is considered to be unstable and incomplete. Also, there seemed to be no apparent difference in the length of the calls compared to the voice pitch. It is thought that this is because they don't yet have the ability to control the voice pitch when they first begin to call. They appear to be able to slightly adjust the length of the phrase early on. And they gradually develop the ability to control the pitch and finally details of each phrase (shape of voiceprint) are arranged into a standard call.

2)All Japanese Green Pigeons seem to develop the standard call in about 1 year after birth though it is still unstable.

3)Calls in the wild at the first peak of the number of calls are made during the time when Gyotoku Female 17 has not begun “oao” call including up to 10th phrase. This is thought to be because the wild population consists of adult birds.

4)The time when “oao” calls of Gyotoku Female 17 increase was after the trough on June 28. This coincides well with the assumption by Komatan (2018) “Calls of the population born in the previous year become the standard call as it calls frequently after June 28” .

5)Pigeons are not songbirds and they do not sing but only have certain calls. By its completion it may be said that a condition to get a mate is met but considering that “popopo” call was not made in their second year it is assumed that individuals in the second year after the birth do not breed that year. In the transition period till the standard call is made during survey period, the call with all 10 phrases (standard call) was made from 7/20 to 8/21. Even thought it is considered the standard call, 1st phase and the length of the call was still unstable.

6)The fact that the call of reared and non-breeding Gyotoku Female 17 (born in the previous year) showed the similar seasonal cycle of calls as wild Japanese Green Pigeons suggests that the secretion status of the hormone level with regard to the call was in the same seasonal cycle. This may be because their ability to control the voice pitch has not yet been developed when they start to call. It seems that they can make the delicate adjustment of the length of phrases at an early stage and then the ability to control the voice pitch is gradually developed, and finally the details of each phrase (shape of voiceprint) is arranged into the standard call.

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.

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.

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.

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).

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.

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.

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.

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.

A camera-trap survey with an automatic infrared sensor camera was conducted from 2008 to 2017 in Yokohama Nature Sanctuary as part of a medium and large-sized mammal survey of the “Monitoring Sites 1000 Satoyama” project. The changes in the animals and diel activities over 10 years were analyzed.

1 There were 3 species of native animals (Racoon Dog, Japanese Hare, Japanese Weasel) and 1 genus of mice (Large Japanese Field Mouse or Small Japanese Field Mouse), 3 introduced species (Formosan Squirrel, Raccoon, Masked Civet) and 2 other species (cat, dog) that were photographed. Also 16 species of birds photographed including 2 species of introduced birds (Chinese Bamboo Partridge, Chinese Hwamei).

2 Declining trends were seen in Japanese Hare (about 30% decrease), Formosan Squirrel (about 20% decrease), Masked Civet (about 10% decrease), Racoon (about 10% before capture, about 20% after capture) . Increasing trends were seen in Racoon Dogs (about 20% increase), mice (about 15%), cats (about 15%) and Chinese Hwamei (about 70%)

3 Species with the same trend of increase/decrease as the entire country were the decline of Japanese Hare and an increase in Racoon Dog and Chinese Hwamei. Masked Civet and Raccoon showed an increase nationwide but a decrease at the Yokohama Nature Sanctuary.

4 Diel activity show that Raccoon Dogs, mice, Masked Civet and Raccoon are nocturnal with over 90% of photographs being at night. And diel activities show that Formosan Squirrel, Chinese bamboo partridge and Chinese Hwamei were photographed about 100% during the day. Japanese hare and stray/feral cats were active both day and night (the ratio of night time photography was about 50%).

The behavior of the Great Tits during their nesting period was observed by installing an infrared camera in their nestbox. Nest making began on March 16 and the chicks fledged on May 8 (54 days).

We observed a relationship between rainfall, humidity and the amount of sunlight. Incubation time was shorter on rainy days. On days of heavy rainfall, it is difficult to procure food so it is assumed that the incubation time was shorter due to the necessity of the female parent out getting food for herself.

It could be seen that during the breeding season the amount of food for the chicks decreased on rainy days and this affected their growth. Also, the number of feedings per day increased during the 1st to 5th days and decreased thereafter. This is due to the size of insects that the parent birds fed the chicks. At first they were fed small insects and then gradually fed larger insects as the chicks body size increased so the total amount of food increased as the number of feedings decreased.

Once the chicks obtained a certain amount of feathers the parent birds did not need too brood anymore during the day, however, they were also observed brooding on some nights. This was on rainy days when the chicks got wet when fed by the parent that has been soaked in the rain. To help the chicks maintain their body heat and not weaken the parent brooded to warm the chicks with their own body heat.

A Wilson's Storm-petrel Oceanites oceanicus was observed in Sagami Bay on June 2, 2018. The individual was identified as an adult and sex unknown. This is the first observation record for Kanagawa Prefecture.

While birdwatching in Mt. Koma I heard a familiar bird singing but I could not immediately recognize which bird it was. Unfortunately I did not have a voice recorder so I took a video with the camera indicated above. Later, I extracted the audio file from the video and handed it to Mr. Michio Matsuda for an evaluation. Mr. Michio Matsuda confirmed that it was the voice of a Black-Naped Oriole.