Sighting of Japanese Green Pigeon with red throat area

<p>On rare occasions Japanese Green Pigeons with red from their throats to chests can be observed along with others that arrive at Terugasaki Beach in Oiso Town, Kanagawa Prefecture. In this study we investigated the reason for this red color on the throat of these Pigeons by determining what fruit they were eating during the period of time that they were observed at Terugasaki.</p><p>1. From 2010~2016 the results of the arrival survey of Japanese Green Pigeons at Terugaski showed a total number of 168610 birds with 177 having red throats. Appearance rate of 0.10% </p><p>2.Arrival of Japanese Green Pigeon from 2010~2016 were mainly from June to September with most concentrated in June and July, and again a few appearing in September. With the exception of August 2012 (34) and 2014 (2), there were none at other times. </p><p>3. From 2010~2016 the sex of 147 birds were identified. Males: 73.5%, females:26.5% </p><p>4. From 2010~2016 all Japanese Green Pigeon wth red throats were adults. There were no observations of juveniles with red throats. </p><p>5.Compared to other years 2016 had over twice the amount of observations so we used this information for further study. Below are the findings from this study: </p><p>① Of the 42529 observations there were 24 Japanese Green Pigeon with red throats with an appearance rate of 0.06%. </p><p>② Japanese Green Pigeon with red throats were observed from June ~ September with most in June and July. A few were observed in September and none in August. </p><p>③ The sex of 20 birds was identified: male 90%, female 10%. </p><p>④ Observation rates of the 42529 birds observed was: male 39%, female 61%. Overall total of observed birds with red throats was: male 0.11%, female 0.01%. When compared, the males appearance rate was 11 times more than females. BINOS vol.24（2017） </p><p>⑤The appearance of Japanese Green Pigeon with red throats can be divided into 2 groups. The first group (first time) was from June 19~July 24, the second was from September 12~September 26. The first arrival of first stage juveniles was from July 18. Observation of first stage juveniles was concentrated from the end of July ~ beginning of September. At this time adults with red throats were also observed. </p><p>6.From 7 years of data (2010~2016), we learned that after the arrival of Japanese Green Pigeons with red throats finished, first stage juveniles also appeared. </p><p>7. We examined several reasons why the Japanese Green Pigeons had red throats. We were able to determine that these birds fed on red berries at the time that their young fledged. The most feasible conclusion is that the Japanese Green Pigeon that flew to Terugasaki fed their fledglings, until they were weaned, on regurgitated red berries. The juice from this ran out of their mouths and onto their throats and chests staining it red.</p>